SQLite4
Changes On Branch nextgen-query-planner
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Changes In Branch nextgen-query-planner Excluding Merge-Ins

This is equivalent to a diff from ed79d6f7fa to ed333d20c7

2013-07-22
12:50
Merge the NGQP branch back into trunk. Currently 12 tests are failing in src4.test (all errors are artifacts of the test code). check-in: 4af30d63ec user: dan tags: trunk
2013-07-20
20:20
Fix for optimization of DISTINCT. Leaf check-in: ed333d20c7 user: dan tags: nextgen-query-planner
16:32
Update test script e_fkey.test. check-in: dd9849225b user: dan tags: nextgen-query-planner
2013-07-18
00:58
Fix a typo in the "key format" documentation. check-in: 4beefed2c9 user: drh tags: trunk
2013-07-16
20:01
Updates to use the next-generation-query-planner from the SQLite3 project. This branch is largely broken. check-in: bc9c9f73c5 user: dan tags: nextgen-query-planner
2013-07-06
23:14
Add tests for sqlite4_num_sub with inf and nan. check-in: ed79d6f7fa user: peterreid tags: trunk
23:07
Change some repetitive num tests into loops. check-in: abaf3f1abd user: peterreid tags: trunk

Changes to src/analyze.c.

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  int regTabname = iMem++;     /* Register containing table name */
  int regIdxname = iMem++;     /* Register containing index name */
  int regStat1 = iMem++;       /* The stat column of sqlite_stat1 */
#ifdef SQLITE4_ENABLE_STAT3
  int regNumEq = regStat1;     /* Number of instances.  Same as regStat1 */
  int regNumLt = iMem++;       /* Number of keys less than regSample */
  int regNumDLt = iMem++;      /* Number of distinct keys less than regSample */

  int regSample = iMem++;      /* The next sample value */

  int regAccum = iMem++;       /* Register to hold Stat3Accum object */
  int regLoop = iMem++;        /* Loop counter */
  int regCount = iMem++;       /* Number of rows in the table or index */
  int regTemp1 = iMem++;       /* Intermediate register */
  int regTemp2 = iMem++;       /* Intermediate register */
  int regNewSample = iMem++;
  int once = 1;                /* One-time initialization */







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  int regTabname = iMem++;     /* Register containing table name */
  int regIdxname = iMem++;     /* Register containing index name */
  int regStat1 = iMem++;       /* The stat column of sqlite_stat1 */
#ifdef SQLITE4_ENABLE_STAT3
  int regNumEq = regStat1;     /* Number of instances.  Same as regStat1 */
  int regNumLt = iMem++;       /* Number of keys less than regSample */
  int regNumDLt = iMem++;      /* Number of distinct keys less than regSample */
#endif
  int regSample = iMem++;      /* The next sample value */
#ifdef SQLITE4_ENABLE_STAT3
  int regAccum = iMem++;       /* Register to hold Stat3Accum object */
  int regLoop = iMem++;        /* Loop counter */
  int regCount = iMem++;       /* Number of rows in the table or index */
  int regTemp1 = iMem++;       /* Intermediate register */
  int regTemp2 = iMem++;       /* Intermediate register */
  int regNewSample = iMem++;
  int once = 1;                /* One-time initialization */

Changes to src/delete.c.

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    ** regSet. After the scan is complete, the VM will loop through the set 
    ** of keys in the RowSet and delete each row. Rows must be deleted after 
    ** the scan is complete because deleting an item can change the scan 
    ** order.  */
    sqlite4VdbeAddOp2(v, OP_Null, 0, regSet);
    VdbeComment((v, "initialize RowSet"));
    pWInfo = sqlite4WhereBegin(
        pParse, pTabList, pWhere, 0, 0, WHERE_DUPLICATES_OK
    );
    if( pWInfo==0 ) goto delete_from_cleanup;
    sqlite4VdbeAddOp2(v, OP_RowKey, iCur, regKey);
    sqlite4VdbeAddOp3(v, OP_RowSetAdd, regSet, 0, regKey);
    sqlite4WhereEnd(pWInfo);

    /* Unless this is a view, open cursors for all indexes on the table







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    ** regSet. After the scan is complete, the VM will loop through the set 
    ** of keys in the RowSet and delete each row. Rows must be deleted after 
    ** the scan is complete because deleting an item can change the scan 
    ** order.  */
    sqlite4VdbeAddOp2(v, OP_Null, 0, regSet);
    VdbeComment((v, "initialize RowSet"));
    pWInfo = sqlite4WhereBegin(
        pParse, pTabList, pWhere, 0, 0, WHERE_DUPLICATES_OK, 0
    );
    if( pWInfo==0 ) goto delete_from_cleanup;
    sqlite4VdbeAddOp2(v, OP_RowKey, iCur, regKey);
    sqlite4VdbeAddOp3(v, OP_RowSetAdd, regSet, 0, regKey);
    sqlite4WhereEnd(pWInfo);

    /* Unless this is a view, open cursors for all indexes on the table

Changes to src/expr.c.

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**     register = 1
**   }
**
** in order to avoid running the <test if data structure contains null>
** test more often than is necessary.
*/
#ifndef SQLITE4_OMIT_SUBQUERY

int sqlite4FindInIndex(Parse *pParse, Expr *pX, int *prNotFound){
  Index *pIdx;
  int eType = 0;                        /* Type of RHS table. IN_INDEX_* */
  int iTab = pParse->nTab++;            /* Cursor of the RHS table */
  Vdbe *v = sqlite4GetVdbe(pParse);     /* Virtual machine being coded */

  assert( pX->op==TK_IN );







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**     register = 1
**   }
**
** in order to avoid running the <test if data structure contains null>
** test more often than is necessary.
*/
#ifndef SQLITE4_OMIT_SUBQUERY
#if 0
int sqlite4FindInIndex(Parse *pParse, Expr *pX, int *prNotFound){
  Index *pIdx;
  int eType = 0;                        /* Type of RHS table. IN_INDEX_* */
  int iTab = pParse->nTab++;            /* Cursor of the RHS table */
  Vdbe *v = sqlite4GetVdbe(pParse);     /* Virtual machine being coded */

  assert( pX->op==TK_IN );
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    pParse->nQueryLoop = savedNQueryLoop;
  }
  
  return eType;
}
#endif














































































































































































/*
** Generate code for scalar subqueries used as a subquery expression, EXISTS,
** or IN operators.  Examples:
**
**     (SELECT a FROM b)          -- subquery
**     EXISTS (SELECT a FROM b)   -- EXISTS subquery
**     x IN (4,5,11)              -- IN operator with list on right-hand side







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    pParse->nQueryLoop = savedNQueryLoop;
  }
  
  return eType;
}
#endif

/*
** This function is used by the implementation of the IN (...) operator.
** The pX parameter is the expression on the RHS of the IN operator, which
** might be either a list of expressions or a subquery.
**
** The job of this routine is to find or create a b-tree object that can
** be used either to test for membership in the RHS set or to iterate through
** all members of the RHS set, skipping duplicates.
**
** A cursor is opened on the b-tree object that the RHS of the IN operator
** and pX->iTable is set to the index of that cursor.
**
** The returned value of this function indicates the b-tree type, as follows:
**
**   IN_INDEX_ROWID      - The cursor was opened on a database table.
**   IN_INDEX_INDEX_ASC  - The cursor was opened on an ascending index.
**   IN_INDEX_INDEX_DESC - The cursor was opened on a descending index.
**   IN_INDEX_EPH        - The cursor was opened on a specially created and
**                         populated epheremal table.
**
** An existing b-tree might be used if the RHS expression pX is a simple
** subquery such as:
**
**     SELECT <column> FROM <table>
**
** If the RHS of the IN operator is a list or a more complex subquery, then
** an ephemeral table might need to be generated from the RHS and then
** pX->iTable made to point to the ephermeral table instead of an
** existing table.  
**
** If the prNotFound parameter is 0, then the b-tree will be used to iterate
** through the set members, skipping any duplicates. In this case an
** epheremal table must be used unless the selected <column> is guaranteed
** to be unique - either because it is an INTEGER PRIMARY KEY or it
** has a UNIQUE constraint or UNIQUE index.
**
** If the prNotFound parameter is not 0, then the b-tree will be used 
** for fast set membership tests. In this case an epheremal table must 
** be used unless <column> is an INTEGER PRIMARY KEY or an index can 
** be found with <column> as its left-most column.
**
** When the b-tree is being used for membership tests, the calling function
** needs to know whether or not the structure contains an SQL NULL 
** value in order to correctly evaluate expressions like "X IN (Y, Z)".
** If there is any chance that the (...) might contain a NULL value at
** runtime, then a register is allocated and the register number written
** to *prNotFound. If there is no chance that the (...) contains a
** NULL value, then *prNotFound is left unchanged.
**
** If a register is allocated and its location stored in *prNotFound, then
** its initial value is NULL.  If the (...) does not remain constant
** for the duration of the query (i.e. the SELECT within the (...)
** is a correlated subquery) then the value of the allocated register is
** reset to NULL each time the subquery is rerun. This allows the
** caller to use vdbe code equivalent to the following:
**
**   if( register==NULL ){
**     has_null = <test if data structure contains null>
**     register = 1
**   }
**
** in order to avoid running the <test if data structure contains null>
** test more often than is necessary.
*/
int sqlite4FindInIndex(Parse *pParse, Expr *pX, int *prNotFound){
  Select *p;                            /* SELECT to the right of IN operator */
  int eType = 0;                        /* Type of RHS table. IN_INDEX_* */
  int iTab = pParse->nTab++;            /* Cursor of the RHS table */
  int mustBeUnique = (prNotFound==0);   /* True if RHS must be unique */
  Vdbe *v = sqlite4GetVdbe(pParse);     /* Virtual machine being coded */

  assert( pX->op==TK_IN );

  /* Check to see if an existing table or index can be used to
  ** satisfy the query.  This is preferable to generating a new 
  ** ephemeral table.
  */
  p = (ExprHasProperty(pX, EP_xIsSelect) ? pX->x.pSelect : 0);
  if( ALWAYS(pParse->nErr==0) && isCandidateForInOpt(p) && prNotFound ){
    sqlite4 *db = pParse->db;              /* Database connection */
    Table *pTab;                           /* Table <table>. */
    Expr *pExpr;                           /* Expression <column> */
    int iCol;                              /* Index of column <column> */
    int iDb;                               /* Database idx for pTab */

    assert( p );                        /* Because of isCandidateForInOpt(p) */
    assert( p->pEList!=0 );             /* Because of isCandidateForInOpt(p) */
    assert( p->pEList->a[0].pExpr!=0 ); /* Because of isCandidateForInOpt(p) */
    assert( p->pSrc!=0 );               /* Because of isCandidateForInOpt(p) */
    pTab = p->pSrc->a[0].pTab;
    pExpr = p->pEList->a[0].pExpr;
    iCol = pExpr->iColumn;
   
    /* Code an OP_VerifyCookie for <table>. */
    iDb = sqlite4SchemaToIndex(db, pTab->pSchema);
    sqlite4CodeVerifySchema(pParse, iDb);

    /* This function is only called from two places. In both cases the vdbe
    ** has already been allocated. So assume sqlite4GetVdbe() is always
    ** successful here.
    */
    assert(v);
#if 0
    if( iCol<0 ){
      int iAddr;

      iAddr = sqlite4CodeOnce(pParse);

      sqlite4OpenTable(pParse, iTab, iDb, pTab, OP_OpenRead);
      eType = IN_INDEX_ROWID;

      sqlite4VdbeJumpHere(v, iAddr);
    }else
#endif
    {
      Index *pIdx;                         /* Iterator variable */

      /* The collation sequence used by the comparison. If an index is to
      ** be used in place of a temp-table, it must be ordered according
      ** to this collation sequence.  */
      CollSeq *pReq = sqlite4BinaryCompareCollSeq(pParse, pX->pLeft, pExpr);

      /* Check that the affinity that will be used to perform the 
      ** comparison is the same as the affinity of the column. If
      ** it is not, it is not possible to use any index.
      */
      int affinity_ok = sqlite4IndexAffinityOk(pX, pTab->aCol[iCol].affinity);

      for(pIdx=pTab->pIndex; pIdx && eType==0 && affinity_ok; pIdx=pIdx->pNext){
        if( (pIdx->aiColumn[0]==iCol)
         && sqlite4FindCollSeq(db, pIdx->azColl[0], 0)==pReq
         && (!mustBeUnique || (pIdx->nColumn==1 && pIdx->onError!=OE_None))
        ){
          int iAddr;
  
          iAddr = sqlite4CodeOnce(pParse);
          sqlite4OpenIndex(pParse, iTab, iDb, pIdx, OP_OpenRead);
          assert( IN_INDEX_INDEX_DESC == IN_INDEX_INDEX_ASC+1 );
          eType = IN_INDEX_INDEX_ASC + pIdx->aSortOrder[0];

          sqlite4VdbeJumpHere(v, iAddr);
          if( prNotFound && !pTab->aCol[iCol].notNull ){
            *prNotFound = ++pParse->nMem;
            sqlite4VdbeAddOp2(v, OP_Null, 0, *prNotFound);
          }
        }
      }
    }
  }

  if( eType==0 ){
    /* Could not found an existing table or index to use as the RHS b-tree.
    ** We will have to generate an ephemeral table to do the job.
    */
    u32 savedNQueryLoop = pParse->nQueryLoop;
    int rMayHaveNull = 0;
    eType = IN_INDEX_EPH;
    if( prNotFound ){
      *prNotFound = rMayHaveNull = ++pParse->nMem;
      sqlite4VdbeAddOp2(v, OP_Null, 0, *prNotFound);
    }else{
      testcase( pParse->nQueryLoop>0 );
      pParse->nQueryLoop = 0;
    }
    sqlite4CodeSubselect(pParse, pX, rMayHaveNull, eType==IN_INDEX_ROWID);
    pParse->nQueryLoop = savedNQueryLoop;
  }else{
    pX->iTable = iTab;
  }
  return eType;
}
#endif

/*
** Generate code for scalar subqueries used as a subquery expression, EXISTS,
** or IN operators.  Examples:
**
**     (SELECT a FROM b)          -- subquery
**     EXISTS (SELECT a FROM b)   -- EXISTS subquery
**     x IN (4,5,11)              -- IN operator with list on right-hand side

Changes to src/fkey.c.

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  sNameContext.pSrcList = pSrc;
  sNameContext.pParse = pParse;
  sqlite4ResolveExprNames(&sNameContext, pWhere);

  /* Create VDBE to loop through the entries in pSrc that match the WHERE
  ** clause. For each row found, increment the relevant constraint counter
  ** by nIncr.  */
  pWInfo = sqlite4WhereBegin(pParse, pSrc, pWhere, 0, 0, 0);
  if( nIncr>0 && pFKey->isDeferred==0 ){
    sqlite4ParseToplevel(pParse)->mayAbort = 1;
  }
  sqlite4VdbeAddOp2(v, OP_FkCounter, pFKey->isDeferred, nIncr);
  if( pWInfo ){
    sqlite4WhereEnd(pWInfo);
  }







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  sNameContext.pSrcList = pSrc;
  sNameContext.pParse = pParse;
  sqlite4ResolveExprNames(&sNameContext, pWhere);

  /* Create VDBE to loop through the entries in pSrc that match the WHERE
  ** clause. For each row found, increment the relevant constraint counter
  ** by nIncr.  */
  pWInfo = sqlite4WhereBegin(pParse, pSrc, pWhere, 0, 0, 0, 0);
  if( nIncr>0 && pFKey->isDeferred==0 ){
    sqlite4ParseToplevel(pParse)->mayAbort = 1;
  }
  sqlite4VdbeAddOp2(v, OP_FkCounter, pFKey->isDeferred, nIncr);
  if( pWInfo ){
    sqlite4WhereEnd(pWInfo);
  }

Changes to src/select.c.

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  }

  /* Aggregate and non-aggregate queries are handled differently */
  if( !isAgg && pGroupBy==0 ){
    ExprList *pDist = (isDistinct ? p->pEList : 0);

    /* Begin the database scan. */
    pWInfo = sqlite4WhereBegin(pParse, pTabList, pWhere, &pOrderBy, pDist, 0);
    if( pWInfo==0 ) goto select_end;

    if( pWInfo->nRowOut < p->nSelectRow ) p->nSelectRow = pWInfo->nRowOut;



    /* If sorting index that was created by a prior OP_OpenEphemeral 
    ** instruction ended up not being needed, then change the OP_OpenEphemeral
    ** into an OP_Noop.
    */
    if( addrSortIndex>=0 && pOrderBy==0 ){
      sqlite4VdbeChangeToNoop(v, addrSortIndex);
      p->addrOpenEphm[2] = -1;
    }

    if( pWInfo->eDistinct ){
      VdbeOp *pOp;                /* No longer required OpenEphemeral instr. */
     
      assert( addrDistinctIndex>=0 );
      pOp = sqlite4VdbeGetOp(v, addrDistinctIndex);

      assert( isDistinct );
      assert( pWInfo->eDistinct==WHERE_DISTINCT_ORDERED 
           || pWInfo->eDistinct==WHERE_DISTINCT_UNIQUE 
      );
      distinct = -1;
      if( pWInfo->eDistinct==WHERE_DISTINCT_ORDERED ){
        int iJump;
        int iExpr;
        int iFlag = ++pParse->nMem;
        int iBase = pParse->nMem+1;
        int iBase2 = iBase + pEList->nExpr;
        pParse->nMem += (pEList->nExpr*2);








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  }

  /* Aggregate and non-aggregate queries are handled differently */
  if( !isAgg && pGroupBy==0 ){
    ExprList *pDist = (isDistinct ? p->pEList : 0);

    /* Begin the database scan. */
    pWInfo = sqlite4WhereBegin(pParse, pTabList, pWhere, pOrderBy, pDist, 0, 0);
    if( pWInfo==0 ) goto select_end;
    if( sqlite4WhereOutputRowCount(pWInfo)<p->nSelectRow ){
      p->nSelectRow = sqlite4WhereOutputRowCount(pWInfo);
    }
    if( pOrderBy && sqlite4WhereIsOrdered(pWInfo) ) pOrderBy = 0;

    /* If sorting index that was created by a prior OP_OpenEphemeral 
    ** instruction ended up not being needed, then change the OP_OpenEphemeral
    ** into an OP_Noop.
    */
    if( addrSortIndex>=0 && pOrderBy==0 ){
      sqlite4VdbeChangeToNoop(v, addrSortIndex);
      p->addrOpenEphm[2] = -1;
    }

    if( sqlite4WhereIsDistinct(pWInfo) ){
      VdbeOp *pOp;                /* No longer required OpenEphemeral instr. */
     
      assert( addrDistinctIndex>=0 );
      pOp = sqlite4VdbeGetOp(v, addrDistinctIndex);

      assert( isDistinct );
      assert( sqlite4WhereIsDistinct(pWInfo)==WHERE_DISTINCT_ORDERED 
           || sqlite4WhereIsDistinct(pWInfo)==WHERE_DISTINCT_UNIQUE 
      );
      distinct = -1;
      if( sqlite4WhereIsDistinct(pWInfo)==WHERE_DISTINCT_ORDERED ){
        int iJump;
        int iExpr;
        int iFlag = ++pParse->nMem;
        int iBase = pParse->nMem+1;
        int iBase2 = iBase + pEList->nExpr;
        pParse->nMem += (pEList->nExpr*2);

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4016
4017
4018
4019
4020

4021
4022
4023
4024
4025
4026
4027
        sqlite4VdbeAddOp2(v, OP_If, iFlag, iJump-1);
        for(iExpr=0; iExpr<pEList->nExpr; iExpr++){
          CollSeq *pColl = sqlite4ExprCollSeq(pParse, pEList->a[iExpr].pExpr);
          sqlite4VdbeAddOp3(v, OP_Ne, iBase+iExpr, iJump, iBase2+iExpr);
          sqlite4VdbeChangeP4(v, -1, (const char *)pColl, P4_COLLSEQ);
          sqlite4VdbeChangeP5(v, SQLITE4_NULLEQ);
        }
        sqlite4VdbeAddOp2(v, OP_Goto, 0, pWInfo->iContinue);

        sqlite4VdbeAddOp2(v, OP_Integer, 0, iFlag);
        assert( sqlite4VdbeCurrentAddr(v)==iJump );
        sqlite4VdbeAddOp3(v, OP_Move, iBase, iBase2, pEList->nExpr);
      }else{
        pOp->opcode = OP_Noop;
      }
    }

    /* Use the standard inner loop. */
    selectInnerLoop(pParse, p, pEList, 0, 0, pOrderBy, distinct, pDest,
                    pWInfo->iContinue, pWInfo->iBreak);


    /* End the database scan loop.
    */
    sqlite4WhereEnd(pWInfo);
  }else{
    /* This is the processing for aggregate queries */
    NameContext sNC;    /* Name context for processing aggregate information */







|











|
>







4004
4005
4006
4007
4008
4009
4010
4011
4012
4013
4014
4015
4016
4017
4018
4019
4020
4021
4022
4023
4024
4025
4026
4027
4028
4029
4030
4031
        sqlite4VdbeAddOp2(v, OP_If, iFlag, iJump-1);
        for(iExpr=0; iExpr<pEList->nExpr; iExpr++){
          CollSeq *pColl = sqlite4ExprCollSeq(pParse, pEList->a[iExpr].pExpr);
          sqlite4VdbeAddOp3(v, OP_Ne, iBase+iExpr, iJump, iBase2+iExpr);
          sqlite4VdbeChangeP4(v, -1, (const char *)pColl, P4_COLLSEQ);
          sqlite4VdbeChangeP5(v, SQLITE4_NULLEQ);
        }
        sqlite4VdbeAddOp2(v, OP_Goto, 0, sqlite4WhereContinueLabel(pWInfo));

        sqlite4VdbeAddOp2(v, OP_Integer, 0, iFlag);
        assert( sqlite4VdbeCurrentAddr(v)==iJump );
        sqlite4VdbeAddOp3(v, OP_Move, iBase, iBase2, pEList->nExpr);
      }else{
        pOp->opcode = OP_Noop;
      }
    }

    /* Use the standard inner loop. */
    selectInnerLoop(pParse, p, pEList, 0, 0, pOrderBy, distinct, pDest,
        sqlite4WhereContinueLabel(pWInfo), sqlite4WhereBreakLabel(pWInfo)
    );

    /* End the database scan loop.
    */
    sqlite4WhereEnd(pWInfo);
  }else{
    /* This is the processing for aggregate queries */
    NameContext sNC;    /* Name context for processing aggregate information */
4123
4124
4125
4126
4127
4128
4129
4130
4131
4132
4133
4134
4135
4136
4137
4138
4139
4140
4141
4142
4143
4144

      /* Begin a loop that will extract all source rows in GROUP BY order.
      ** This might involve two separate loops with an OP_Sort in between, or
      ** it might be a single loop that uses an index to extract information
      ** in the right order to begin with.
      */
      sqlite4VdbeAddOp2(v, OP_Gosub, regReset, addrReset);
      pWInfo = sqlite4WhereBegin(pParse, pTabList, pWhere, &pGroupBy, 0, 0);
      if( pWInfo==0 ) goto select_end;
      if( pGroupBy==0 ){
        /* The optimizer is able to deliver rows in group by order so
        ** we do not have to sort.  The OP_OpenEphemeral table will be
        ** cancelled later because we still need to use the pKeyInfo
        */
        pGroupBy = p->pGroupBy;
        groupBySort = 0;

        /* Evaluate the current GROUP BY terms and store in b0, b1, b2...
        ** (b0 is memory location iBMem+0, b1 is iBMem+1, and so forth)
        ** Then compare the current GROUP BY terms against the GROUP BY terms
        ** from the previous row currently stored in a0, a1, a2...
        */







|

|


|

<







4127
4128
4129
4130
4131
4132
4133
4134
4135
4136
4137
4138
4139
4140

4141
4142
4143
4144
4145
4146
4147

      /* Begin a loop that will extract all source rows in GROUP BY order.
      ** This might involve two separate loops with an OP_Sort in between, or
      ** it might be a single loop that uses an index to extract information
      ** in the right order to begin with.
      */
      sqlite4VdbeAddOp2(v, OP_Gosub, regReset, addrReset);
      pWInfo = sqlite4WhereBegin(pParse, pTabList, pWhere, pGroupBy, 0, 0, 0);
      if( pWInfo==0 ) goto select_end;
      if( sqlite4WhereIsOrdered(pWInfo) ){
        /* The optimizer is able to deliver rows in group by order so
        ** we do not have to sort.  The OP_OpenEphemeral table will be
        ** cancelled later because we still need to use the pKeyInfo.
        */

        groupBySort = 0;

        /* Evaluate the current GROUP BY terms and store in b0, b1, b2...
        ** (b0 is memory location iBMem+0, b1 is iBMem+1, and so forth)
        ** Then compare the current GROUP BY terms against the GROUP BY terms
        ** from the previous row currently stored in a0, a1, a2...
        */
4335
4336
4337
4338
4339
4340
4341
4342
4343
4344
4345
4346
4347
4348
4349
4350
4351
4352
4353
4354
4355
4356
        }
  
        /* This case runs if the aggregate has no GROUP BY clause.  The
        ** processing is much simpler since there is only a single row
        ** of output.
        */
        resetAccumulator(pParse, &sAggInfo);
        pWInfo = sqlite4WhereBegin(pParse, pTabList, pWhere, &pMinMax, 0, flag);
        if( pWInfo==0 ){
          sqlite4ExprListDelete(db, pDel);
          goto select_end;
        }
        updateAccumulator(pParse, &sAggInfo);
        if( !pMinMax && flag ){
          sqlite4VdbeAddOp2(v, OP_Goto, 0, pWInfo->iBreak);
          VdbeComment((v, "%s() by index",
                (flag==WHERE_ORDERBY_MIN?"min":"max")));
        }
        sqlite4WhereEnd(pWInfo);
        finalizeAggFunctions(pParse, &sAggInfo);
      }








|





|
|







4338
4339
4340
4341
4342
4343
4344
4345
4346
4347
4348
4349
4350
4351
4352
4353
4354
4355
4356
4357
4358
4359
        }
  
        /* This case runs if the aggregate has no GROUP BY clause.  The
        ** processing is much simpler since there is only a single row
        ** of output.
        */
        resetAccumulator(pParse, &sAggInfo);
        pWInfo = sqlite4WhereBegin(pParse, pTabList, pWhere, pMinMax, 0,flag,0);
        if( pWInfo==0 ){
          sqlite4ExprListDelete(db, pDel);
          goto select_end;
        }
        updateAccumulator(pParse, &sAggInfo);
        if( sqlite4WhereIsOrdered(pWInfo) && flag ){
          sqlite4VdbeAddOp2(v, OP_Goto, 0, sqlite4WhereBreakLabel(pWInfo));
          VdbeComment((v, "%s() by index",
                (flag==WHERE_ORDERBY_MIN?"min":"max")));
        }
        sqlite4WhereEnd(pWInfo);
        finalizeAggFunctions(pParse, &sAggInfo);
      }

Changes to src/sqliteInt.h.

345
346
347
348
349
350
351






352
353
354
355
356
357
358
** GCC does not define the offsetof() macro so we'll have to do it
** ourselves.
*/
#ifndef offsetof
#define offsetof(STRUCTURE,FIELD) ((int)((char*)&((STRUCTURE*)0)->FIELD))
#endif







/*
** Check to see if this machine uses EBCDIC.  (Yes, believe it or
** not, there are still machines out there that use EBCDIC.)
*/
#if 'A' == '\301'
# define SQLITE4_EBCDIC 1
#else







>
>
>
>
>
>







345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
** GCC does not define the offsetof() macro so we'll have to do it
** ourselves.
*/
#ifndef offsetof
#define offsetof(STRUCTURE,FIELD) ((int)((char*)&((STRUCTURE*)0)->FIELD))
#endif

/* 
** Macros to compute minimum and maximum of two numbers.
*/
#define MIN(A,B) ((A)<(B)?(A):(B))
#define MAX(A,B) ((A)>(B)?(A):(B))

/*
** Check to see if this machine uses EBCDIC.  (Yes, believe it or
** not, there are still machines out there that use EBCDIC.)
*/
#if 'A' == '\301'
# define SQLITE4_EBCDIC 1
#else
527
528
529
530
531
532
533





534
535
536
537
538
539
540

/*
** A convenience macro that returns the number of elements in
** an array.
*/
#define ArraySize(X)    ((int)(sizeof(X)/sizeof(X[0])))






/*
** The following macros are used to suppress compiler warnings and to
** make it clear to human readers when a function parameter is deliberately 
** left unused within the body of a function. This usually happens when
** a function is called via a function pointer. For example the 
** implementation of an SQL aggregate step callback may not use the
** parameter indicating the number of arguments passed to the aggregate,







>
>
>
>
>







533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551

/*
** A convenience macro that returns the number of elements in
** an array.
*/
#define ArraySize(X)    ((int)(sizeof(X)/sizeof(X[0])))

/*
** Determine if the argument is a power of two
*/
#define IsPowerOfTwo(X) (((X)&((X)-1))==0)

/*
** The following macros are used to suppress compiler warnings and to
** make it clear to human readers when a function parameter is deliberately 
** left unused within the body of a function. This usually happens when
** a function is called via a function pointer. For example the 
** implementation of an SQL aggregate step callback may not use the
** parameter indicating the number of arguments passed to the aggregate,
919
920
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924
925







926
927
928
929
930
931
932
#define SQLITE4_IndexCover     0x10     /* Disable index covering table */
#define SQLITE4_GroupByOrder   0x20     /* Disable GROUPBY cover of ORDERBY */
#define SQLITE4_FactorOutConst 0x40     /* Disable factoring out constants */
#define SQLITE4_IdxRealAsInt   0x80     /* Store REAL as INT in indices */
#define SQLITE4_DistinctOpt    0x80     /* DISTINCT using indexes */
#define SQLITE4_OptMask        0xff     /* Mask of all disablable opts */








/*
** Possible values for the sqlite.magic field.
** The numbers are obtained at random and have no special meaning, other
** than being distinct from one another.
*/
#define SQLITE4_MAGIC_OPEN    0x4d06c919  /* Database is open */
#define SQLITE4_MAGIC_CLOSED  0x5f2246b4  /* Database is closed */







>
>
>
>
>
>
>







930
931
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933
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940
941
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943
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946
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949
950
#define SQLITE4_IndexCover     0x10     /* Disable index covering table */
#define SQLITE4_GroupByOrder   0x20     /* Disable GROUPBY cover of ORDERBY */
#define SQLITE4_FactorOutConst 0x40     /* Disable factoring out constants */
#define SQLITE4_IdxRealAsInt   0x80     /* Store REAL as INT in indices */
#define SQLITE4_DistinctOpt    0x80     /* DISTINCT using indexes */
#define SQLITE4_OptMask        0xff     /* Mask of all disablable opts */

/*
** Some new things pulled in from SQLite3 use these macros. todo: Replace
** them with working versions.
*/
#define OptimizationDisabled(db, mask)  0
#define OptimizationEnabled(db, mask)  1

/*
** Possible values for the sqlite.magic field.
** The numbers are obtained at random and have no special meaning, other
** than being distinct from one another.
*/
#define SQLITE4_MAGIC_OPEN    0x4d06c919  /* Database is open */
#define SQLITE4_MAGIC_CLOSED  0x5f2246b4  /* Database is closed */
1382
1383
1384
1385
1386
1387
1388


1389
1390
1391
1392
1393
1394
1395
  char **azColl;   /* Array of collation sequence names for index */
#ifdef SQLITE4_ENABLE_STAT3
  int nSample;             /* Number of elements in aSample[] */
  tRowcnt avgEq;           /* Average nEq value for key values not in aSample */
  IndexSample *aSample;    /* Samples of the left-most key */
#endif
  Fts5Index *pFts; /* Fts5 data (or NULL if this is not an fts index) */


};

/* Index.eIndexType must be set to one of the following. */
#define SQLITE4_INDEX_USER       0 /* Index created by CREATE INDEX statement */
#define SQLITE4_INDEX_UNIQUE     1 /* Index created by UNIQUE constraint */
#define SQLITE4_INDEX_PRIMARYKEY 2 /* Index is the tables PRIMARY KEY */
#define SQLITE4_INDEX_FTS5       3 /* Index is an FTS5 index */







>
>







1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
  char **azColl;   /* Array of collation sequence names for index */
#ifdef SQLITE4_ENABLE_STAT3
  int nSample;             /* Number of elements in aSample[] */
  tRowcnt avgEq;           /* Average nEq value for key values not in aSample */
  IndexSample *aSample;    /* Samples of the left-most key */
#endif
  Fts5Index *pFts; /* Fts5 data (or NULL if this is not an fts index) */

  unsigned bUnordered:1;   /* Use this index for == or IN queries only */
};

/* Index.eIndexType must be set to one of the following. */
#define SQLITE4_INDEX_USER       0 /* Index created by CREATE INDEX statement */
#define SQLITE4_INDEX_UNIQUE     1 /* Index created by UNIQUE constraint */
#define SQLITE4_INDEX_PRIMARYKEY 2 /* Index is the tables PRIMARY KEY */
#define SQLITE4_INDEX_FTS5       3 /* Index is an FTS5 index */
1840
1841
1842
1843
1844
1845
1846

1847
1848
1849
1850
1851
1852
1853
  union {
    Index *pIdx;                   /* Index when WHERE_INDEXED is true */
    struct WhereTerm *pTerm;       /* WHERE clause term for OR-search */
    sqlite4_index_info *pVtabIdx;  /* Virtual table index to use */
  } u;
};


/*
** For each nested loop in a WHERE clause implementation, the WhereInfo
** structure contains a single instance of this structure.  This structure
** is intended to be private the the where.c module and should not be
** access or modified by other modules.
**
** The pIdxInfo field is used to help pick the best index on a







>







1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
  union {
    Index *pIdx;                   /* Index when WHERE_INDEXED is true */
    struct WhereTerm *pTerm;       /* WHERE clause term for OR-search */
    sqlite4_index_info *pVtabIdx;  /* Virtual table index to use */
  } u;
};

#if 0
/*
** For each nested loop in a WHERE clause implementation, the WhereInfo
** structure contains a single instance of this structure.  This structure
** is intended to be private the the where.c module and should not be
** access or modified by other modules.
**
** The pIdxInfo field is used to help pick the best index on a
1883
1884
1885
1886
1887
1888
1889

1890

1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903





















1904
1905
1906
1907
1908
1909
1910
1911

1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927

1928
1929
1930


1931
1932
1933
1934
1935
1936
1937
  ** we need a place to cache virtual table index information for each
  ** virtual table in the FROM clause and the WhereLevel structure is
  ** a convenient place since there is one WhereLevel for each FROM clause
  ** element.
  */
  sqlite4_index_info *pIdxInfo;  /* Index info for n-th source table */
};



/*
** Flags appropriate for the wctrlFlags parameter of sqlite4WhereBegin()
** and the WhereInfo.wctrlFlags member.
*/
#define WHERE_ORDERBY_NORMAL   0x0000 /* No-op */
#define WHERE_ORDERBY_MIN      0x0001 /* ORDER BY processing for min() func */
#define WHERE_ORDERBY_MAX      0x0002 /* ORDER BY processing for max() func */
#define WHERE_ONEPASS_DESIRED  0x0004 /* Want to do one-pass UPDATE/DELETE */
#define WHERE_DUPLICATES_OK    0x0008 /* Ok to return a row more than once */
#define WHERE_OMIT_OPEN_CLOSE  0x0010 /* Table cursors are already open */
#define WHERE_NO_AUTOINDEX     0x0020 /* Do not use an auto-index search */
#define WHERE_ONETABLE_ONLY    0x0040 /* Only code the 1st table in pTabList */
#define WHERE_AND_ONLY         0x0080 /* Don't use indices for OR terms */






















/*
** The WHERE clause processing routine has two halves.  The
** first part does the start of the WHERE loop and the second
** half does the tail of the WHERE loop.  An instance of
** this structure is returned by the first half and passed
** into the second half to give some continuity.
*/

struct WhereInfo {
  Parse *pParse;       /* Parsing and code generating context */
  u16 wctrlFlags;      /* Flags originally passed to sqlite4WhereBegin() */
  u8 okOnePass;        /* Ok to use one-pass algorithm for UPDATE or DELETE */
  u8 untestedTerms;    /* Not all WHERE terms resolved by outer loop */
  u8 eDistinct;
  SrcList *pTabList;             /* List of tables in the join */
  int iTop;                      /* The very beginning of the WHERE loop */
  int iContinue;                 /* Jump here to continue with next record */
  int iBreak;                    /* Jump here to break out of the loop */
  int nLevel;                    /* Number of nested loop */
  struct WhereClause *pWC;       /* Decomposition of the WHERE clause */
  double savedNQueryLoop;        /* pParse->nQueryLoop outside the WHERE loop */
  double nRowOut;                /* Estimated number of output rows */
  WhereLevel a[1];               /* Information about each nest loop in WHERE */
};


#define WHERE_DISTINCT_UNIQUE 1
#define WHERE_DISTINCT_ORDERED 2



/*
** A NameContext defines a context in which to resolve table and column
** names.  The context consists of a list of tables (the pSrcList) field and
** a list of named expression (pEList).  The named expression list may
** be NULL.  The pSrc corresponds to the FROM clause of a SELECT or
** to the table being operated on by INSERT, UPDATE, or DELETE.  The







>

>













>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>








>
















>

|
|
>
>







1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
  ** we need a place to cache virtual table index information for each
  ** virtual table in the FROM clause and the WhereLevel structure is
  ** a convenient place since there is one WhereLevel for each FROM clause
  ** element.
  */
  sqlite4_index_info *pIdxInfo;  /* Index info for n-th source table */
};
#endif

#if 0
/*
** Flags appropriate for the wctrlFlags parameter of sqlite4WhereBegin()
** and the WhereInfo.wctrlFlags member.
*/
#define WHERE_ORDERBY_NORMAL   0x0000 /* No-op */
#define WHERE_ORDERBY_MIN      0x0001 /* ORDER BY processing for min() func */
#define WHERE_ORDERBY_MAX      0x0002 /* ORDER BY processing for max() func */
#define WHERE_ONEPASS_DESIRED  0x0004 /* Want to do one-pass UPDATE/DELETE */
#define WHERE_DUPLICATES_OK    0x0008 /* Ok to return a row more than once */
#define WHERE_OMIT_OPEN_CLOSE  0x0010 /* Table cursors are already open */
#define WHERE_NO_AUTOINDEX     0x0020 /* Do not use an auto-index search */
#define WHERE_ONETABLE_ONLY    0x0040 /* Only code the 1st table in pTabList */
#define WHERE_AND_ONLY         0x0080 /* Don't use indices for OR terms */
#endif


/*
** Flags appropriate for the wctrlFlags parameter of sqlite3WhereBegin()
** and the WhereInfo.wctrlFlags member.
*/
#define WHERE_ORDERBY_NORMAL   0x0000 /* No-op */
#define WHERE_ORDERBY_MIN      0x0001 /* ORDER BY processing for min() func */
#define WHERE_ORDERBY_MAX      0x0002 /* ORDER BY processing for max() func */
#define WHERE_ONEPASS_DESIRED  0x0004 /* Want to do one-pass UPDATE/DELETE */
#define WHERE_DUPLICATES_OK    0x0008 /* Ok to return a row more than once */
#define WHERE_OMIT_OPEN_CLOSE  0x0010 /* Table cursors are already open */
#define WHERE_FORCE_TABLE      0x0020 /* Do not use an index-only search */
#define WHERE_ONETABLE_ONLY    0x0040 /* Only code the 1st table in pTabList */
#define WHERE_AND_ONLY         0x0080 /* Don't use indices for OR terms */
#define WHERE_GROUPBY          0x0100 /* pOrderBy is really a GROUP BY */
#define WHERE_DISTINCTBY       0x0200 /* pOrderby is really a DISTINCT clause */
#define WHERE_WANT_DISTINCT    0x0400 /* All output needs to be distinct */



/*
** The WHERE clause processing routine has two halves.  The
** first part does the start of the WHERE loop and the second
** half does the tail of the WHERE loop.  An instance of
** this structure is returned by the first half and passed
** into the second half to give some continuity.
*/
#if 0
struct WhereInfo {
  Parse *pParse;       /* Parsing and code generating context */
  u16 wctrlFlags;      /* Flags originally passed to sqlite4WhereBegin() */
  u8 okOnePass;        /* Ok to use one-pass algorithm for UPDATE or DELETE */
  u8 untestedTerms;    /* Not all WHERE terms resolved by outer loop */
  u8 eDistinct;
  SrcList *pTabList;             /* List of tables in the join */
  int iTop;                      /* The very beginning of the WHERE loop */
  int iContinue;                 /* Jump here to continue with next record */
  int iBreak;                    /* Jump here to break out of the loop */
  int nLevel;                    /* Number of nested loop */
  struct WhereClause *pWC;       /* Decomposition of the WHERE clause */
  double savedNQueryLoop;        /* pParse->nQueryLoop outside the WHERE loop */
  double nRowOut;                /* Estimated number of output rows */
  WhereLevel a[1];               /* Information about each nest loop in WHERE */
};
#endif

#define WHERE_DISTINCT_NOOP      0
#define WHERE_DISTINCT_UNIQUE    1
#define WHERE_DISTINCT_ORDERED   2
#define WHERE_DISTINCT_UNORDERED 3

/*
** A NameContext defines a context in which to resolve table and column
** names.  The context consists of a list of tables (the pSrcList) field and
** a list of named expression (pEList).  The named expression list may
** be NULL.  The pSrc corresponds to the FROM clause of a SELECT or
** to the table being operated on by INSERT, UPDATE, or DELETE.  The
2722
2723
2724
2725
2726
2727
2728
2729

2730






2731
2732
2733
2734
2735
2736
2737
void sqlite4OpenTable(Parse*, int iCur, int iDb, Table*, int);
#if defined(SQLITE4_ENABLE_UPDATE_DELETE_LIMIT) \
    && !defined(SQLITE4_OMIT_SUBQUERY)
Expr *sqlite4LimitWhere(Parse*,SrcList*,Expr*,ExprList*,Expr*,Expr*,char*);
#endif
void sqlite4DeleteFrom(Parse*, SrcList*, Expr*);
void sqlite4Update(Parse*, SrcList*, ExprList*, Expr*, int);
WhereInfo *sqlite4WhereBegin(Parse*, SrcList*, Expr*, ExprList**,ExprList*,u16);

void sqlite4WhereEnd(WhereInfo*);






int sqlite4ExprCodeGetColumn(Parse*, Table*, int, int, int);
void sqlite4ExprCodeGetColumnOfTable(Vdbe*, Table*, int, int, int);
void sqlite4ExprCodeMove(Parse*, int, int, int);
void sqlite4ExprCodeCopy(Parse*, int, int, int);
void sqlite4ExprCacheStore(Parse*, int, int, int);
void sqlite4ExprCachePush(Parse*);
void sqlite4ExprCachePop(Parse*, int);







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void sqlite4OpenTable(Parse*, int iCur, int iDb, Table*, int);
#if defined(SQLITE4_ENABLE_UPDATE_DELETE_LIMIT) \
    && !defined(SQLITE4_OMIT_SUBQUERY)
Expr *sqlite4LimitWhere(Parse*,SrcList*,Expr*,ExprList*,Expr*,Expr*,char*);
#endif
void sqlite4DeleteFrom(Parse*, SrcList*, Expr*);
void sqlite4Update(Parse*, SrcList*, ExprList*, Expr*, int);
WhereInfo *sqlite4WhereBegin(Parse*,SrcList*,Expr*,ExprList*,ExprList*,u16,int);

void sqlite4WhereEnd(WhereInfo*);
u64 sqlite4WhereOutputRowCount(WhereInfo*);
int sqlite4WhereIsDistinct(WhereInfo*);
int sqlite4WhereIsOrdered(WhereInfo*);
int sqlite4WhereContinueLabel(WhereInfo*);
int sqlite4WhereBreakLabel(WhereInfo*);
int sqlite4WhereOkOnePass(WhereInfo*);
int sqlite4ExprCodeGetColumn(Parse*, Table*, int, int, int);
void sqlite4ExprCodeGetColumnOfTable(Vdbe*, Table*, int, int, int);
void sqlite4ExprCodeMove(Parse*, int, int, int);
void sqlite4ExprCodeCopy(Parse*, int, int, int);
void sqlite4ExprCacheStore(Parse*, int, int, int);
void sqlite4ExprCachePush(Parse*);
void sqlite4ExprCachePop(Parse*, int);
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#else
  #define sqlite4BeginBenignMalloc(X)
  #define sqlite4EndBenignMalloc(X)
#endif

#define IN_INDEX_ROWID           1
#define IN_INDEX_EPH             2
#define IN_INDEX_INDEX           3

int sqlite4FindInIndex(Parse *, Expr *, int*);
Index *sqlite4FindExistingInIndex(Parse *, Expr *, int);


#if SQLITE4_MAX_EXPR_DEPTH>0
  void sqlite4ExprSetHeight(Parse *pParse, Expr *p);
  int sqlite4SelectExprHeight(Select *);







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#else
  #define sqlite4BeginBenignMalloc(X)
  #define sqlite4EndBenignMalloc(X)
#endif

#define IN_INDEX_ROWID           1
#define IN_INDEX_EPH             2
#define IN_INDEX_INDEX_ASC       3
#define IN_INDEX_INDEX_DESC      4
int sqlite4FindInIndex(Parse *, Expr *, int*);
Index *sqlite4FindExistingInIndex(Parse *, Expr *, int);


#if SQLITE4_MAX_EXPR_DEPTH>0
  void sqlite4ExprSetHeight(Parse *pParse, Expr *p);
  int sqlite4SelectExprHeight(Select *);

Changes to src/update.c.

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  **
  ** There is one exception to the above: If static analysis of the WHERE 
  ** clause indicates that the loop will visit at most one row, then the
  ** RowSet object is bypassed and the primary key of the single row (if
  ** any) left in register regOldKey. This is called the "one-pass"
  ** approach. Set okOnePass to true if it can be used in this case.  */
  sqlite4VdbeAddOp3(v, OP_Null, 0, regRowSet, regOldKey);
  pWInfo = sqlite4WhereBegin(pParse, pSrc, pWhere, 0, 0, WHERE_ONEPASS_DESIRED);
  if( pWInfo==0 ) goto update_cleanup;
  okOnePass = pWInfo->okOnePass;
  sqlite4VdbeAddOp2(v, OP_RowKey, iCur+iPk, regOldKey);
  if( !okOnePass ){
    sqlite4VdbeAddOp3(v, OP_RowSetAdd, regRowSet, 0, regOldKey);
  }
  sqlite4WhereEnd(pWInfo);

  /* Open every index that needs updating. If any index could potentially 







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  **
  ** There is one exception to the above: If static analysis of the WHERE 
  ** clause indicates that the loop will visit at most one row, then the
  ** RowSet object is bypassed and the primary key of the single row (if
  ** any) left in register regOldKey. This is called the "one-pass"
  ** approach. Set okOnePass to true if it can be used in this case.  */
  sqlite4VdbeAddOp3(v, OP_Null, 0, regRowSet, regOldKey);
  pWInfo = sqlite4WhereBegin(pParse, pSrc, pWhere, 0,0,WHERE_ONEPASS_DESIRED,0);
  if( pWInfo==0 ) goto update_cleanup;
  okOnePass = sqlite4WhereOkOnePass(pWInfo);
  sqlite4VdbeAddOp2(v, OP_RowKey, iCur+iPk, regOldKey);
  if( !okOnePass ){
    sqlite4VdbeAddOp3(v, OP_RowSetAdd, regRowSet, 0, regOldKey);
  }
  sqlite4WhereEnd(pWInfo);

  /* Open every index that needs updating. If any index could potentially 

Changes to src/vdbe.c.

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      sqlite4VdbeDestroyDecoder(pCodec);
    }
  }else{
    sqlite4VdbeMemSetNull(pDest);
  }
  UPDATE_MAX_BLOBSIZE(pDest);
  REGISTER_TRACE(pOp->p3, pDest);
      assert( rc<100 );
  break;
}

/* Opcode: Affinity P1 P2 * P4 *
**
** Apply affinities to a range of P2 registers starting with P1.
**







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      sqlite4VdbeDestroyDecoder(pCodec);
    }
  }else{
    sqlite4VdbeMemSetNull(pDest);
  }
  UPDATE_MAX_BLOBSIZE(pDest);
  REGISTER_TRACE(pOp->p3, pDest);
  assert( rc<100 );
  break;
}

/* Opcode: Affinity P1 P2 * P4 *
**
** Apply affinities to a range of P2 registers starting with P1.
**

Changes to src/vdbecodec.c.

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    /* Write the encoded key to the output buffer. */
    if( enlargeEncoderAllocation(p, pMem->n*4 + 2) ) return SQLITE4_NOMEM;
    p->aOut[p->nOut++] = 0x24;   /* Text */
    if( pColl==0 || pColl->xMkKey==0 ){
      const char *z = (const char *)sqlite4ValueText(pMem, SQLITE4_UTF8);
      if( z ){
        char *zCsr = z;
        char *zEnd = &z[pMem->n];
        while( *zCsr && zCsr<zEnd ) zCsr++;
        memcpy(p->aOut+p->nOut, z, (zCsr-z));
        p->nOut += (zCsr-z);
      }
    }else{
      int rc;                     /* xMkKey() return code */
      int nReq;                   /* Space required by xMkKey() */







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    /* Write the encoded key to the output buffer. */
    if( enlargeEncoderAllocation(p, pMem->n*4 + 2) ) return SQLITE4_NOMEM;
    p->aOut[p->nOut++] = 0x24;   /* Text */
    if( pColl==0 || pColl->xMkKey==0 ){
      const char *z = (const char *)sqlite4ValueText(pMem, SQLITE4_UTF8);
      if( z ){
        const char *zCsr = z;
        const char *zEnd = &z[pMem->n];
        while( *zCsr && zCsr<zEnd ) zCsr++;
        memcpy(p->aOut+p->nOut, z, (zCsr-z));
        p->nOut += (zCsr-z);
      }
    }else{
      int rc;                     /* xMkKey() return code */
      int nReq;                   /* Space required by xMkKey() */

Changes to src/where.c.

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** indices, you might also think of this module as the "query optimizer".
*/
#include "sqliteInt.h"

/* For VdbeCodecEncodeKey() - revisit this */
#include "vdbeInt.h"


/*
** Trace output macros
*/
#if defined(SQLITE4_TEST) || defined(SQLITE4_DEBUG)
int sqlite4WhereTrace = 0;
#endif
#if defined(SQLITE4_TEST) && defined(SQLITE4_DEBUG)


# define WHERETRACE(X)  if(sqlite4WhereTrace) sqlite4DebugPrintf X
#else
# define WHERETRACE(X)
#endif

/* Forward reference
*/
typedef struct WhereClause WhereClause;
typedef struct WhereMaskSet WhereMaskSet;
typedef struct WhereOrInfo WhereOrInfo;
typedef struct WhereAndInfo WhereAndInfo;

typedef struct WhereCost WhereCost;














































































































































/*
** The query generator uses an array of instances of this structure to
** help it analyze the subexpressions of the WHERE clause.  Each WHERE
** clause subexpression is separated from the others by AND operators,
** usually, or sometimes subexpressions separated by OR.
**







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** indices, you might also think of this module as the "query optimizer".
*/
#include "sqliteInt.h"

/* For VdbeCodecEncodeKey() - revisit this */
#include "vdbeInt.h"


/*
** Trace output macros
*/
#if defined(SQLITE4_TEST) || defined(SQLITE4_DEBUG)
/***/ int sqlite4WhereTrace = 0;
#endif
#if defined(SQLITE4_DEBUG) \
    && (defined(SQLITE4_TEST) || defined(SQLITE4_ENABLE_WHERETRACE))
# define WHERETRACE(K,X)  if(sqlite4WhereTrace&(K)) sqlite4DebugPrintf X
# define WHERETRACE_ENABLED 1
#else
# define WHERETRACE(K,X)
#endif

/* Forward reference
*/
typedef struct WhereClause WhereClause;
typedef struct WhereMaskSet WhereMaskSet;
typedef struct WhereOrInfo WhereOrInfo;
typedef struct WhereAndInfo WhereAndInfo;
typedef struct WhereLevel WhereLevel;
typedef struct WhereLoop WhereLoop;
typedef struct WherePath WherePath;
typedef struct WhereTerm WhereTerm;
typedef struct WhereLoopBuilder WhereLoopBuilder;
typedef struct WhereScan WhereScan;

/*
** Cost X is tracked as 10*log2(X) stored in a 16-bit integer.  The
** maximum cost for ordinary tables is 64*(2**63) which becomes 6900.
** (Virtual tables can return a larger cost, but let's assume they do not.)
** So all costs can be stored in a 16-bit unsigned integer without risk
** of overflow.
**
** Costs are estimates, so don't go to the computational trouble to compute
** 10*log2(X) exactly.  Instead, a close estimate is used.  Any value of
** X<=1 is stored as 0.  X=2 is 10.  X=3 is 16.  X=1000 is 99. etc.
**
** The tool/wherecosttest.c source file implements a command-line program
** that will convert between WhereCost to integers and do addition and
** multiplication on WhereCost values.  That command-line program is a
** useful utility to have around when working with this module.
*/
typedef unsigned short int WhereCost;

/*
** This object contains information needed to implement a single nested
** loop in WHERE clause.
**
** Contrast this object with WhereLoop.  This object describes the
** implementation of the loop.  WhereLoop describes the algorithm.
** This object contains a pointer to the WhereLoop algorithm as one of
** its elements.
**
** The WhereInfo object contains a single instance of this object for
** each term in the FROM clause (which is to say, for each of the
** nested loops as implemented).  The order of WhereLevel objects determines
** the loop nested order, with WhereInfo.a[0] being the outer loop and
** WhereInfo.a[WhereInfo.nLevel-1] being the inner loop.
*/
struct WhereLevel {
  int iLeftJoin;        /* Memory cell used to implement LEFT OUTER JOIN */
  int iTabCur;          /* The VDBE cursor used to access the table */
  int iIdxCur;          /* The VDBE cursor used to access pIdx */
  int addrBrk;          /* Jump here to break out of the loop */
  int addrNxt;          /* Jump here to start the next IN combination */
  int addrCont;         /* Jump here to continue with the next loop cycle */
  int addrFirst;        /* First instruction of interior of the loop */
  u8 iFrom;             /* Which entry in the FROM clause */
  u8 op, p5;            /* Opcode and P5 of the opcode that ends the loop */
  int p1, p2;           /* Operands of the opcode used to ends the loop */
  union {               /* Information that depends on pWLoop->wsFlags */
    struct {
      int nIn;              /* Number of entries in aInLoop[] */
      struct InLoop {
        int iCur;              /* The VDBE cursor used by this IN operator */
        int addrInTop;         /* Top of the IN loop */
        u8 eEndLoopOp;         /* IN Loop terminator. OP_Next or OP_Prev */
      } *aInLoop;           /* Information about each nested IN operator */
    } in;                 /* Used when pWLoop->wsFlags&WHERE_IN_ABLE */
    Index *pCovidx;       /* Possible covering index for WHERE_MULTI_OR */
  } u;
  struct WhereLoop *pWLoop;  /* The selected WhereLoop object */
};

/*
** Each instance of this object represents an algorithm for evaluating one
** term of a join.  Every term of the FROM clause will have at least
** one corresponding WhereLoop object (unless INDEXED BY constraints
** prevent a query solution - which is an error) and many terms of the
** FROM clause will have multiple WhereLoop objects, each describing a
** potential way of implementing that FROM-clause term, together with
** dependencies and cost estimates for using the chosen algorithm.
**
** Query planning consists of building up a collection of these WhereLoop
** objects, then computing a particular sequence of WhereLoop objects, with
** one WhereLoop object per FROM clause term, that satisfy all dependencies
** and that minimize the overall cost.
*/
struct WhereLoop {
  Bitmask prereq;       /* Bitmask of other loops that must run first */
  Bitmask maskSelf;     /* Bitmask identifying table iTab */
#ifdef SQLITE4_DEBUG
  char cId;             /* Symbolic ID of this loop for debugging use */
#endif
  u8 iTab;              /* Position in FROM clause of table for this loop */
  u8 iSortIdx;          /* Sorting index number.  0==None */
  WhereCost rSetup;     /* One-time setup cost (ex: create transient index) */
  WhereCost rRun;       /* Cost of running each loop */
  WhereCost nOut;       /* Estimated number of output rows */
  union {
    struct {               /* Information for internal btree tables */
      int nEq;               /* Number of equality constraints */
      Index *pIndex;         /* Index used, or NULL */
    } btree;
    struct {               /* Information for virtual tables */
      int idxNum;            /* Index number */
      u8 needFree;           /* True if sqlite4_free(idxStr) is needed */
      u8 isOrdered;          /* True if satisfies ORDER BY */
      u16 omitMask;          /* Terms that may be omitted */
      char *idxStr;          /* Index identifier string */
    } vtab;
  } u;
  u32 wsFlags;          /* WHERE_* flags describing the plan */
  u16 nLTerm;           /* Number of entries in aLTerm[] */
  /**** whereLoopXfer() copies fields above ***********************/
# define WHERE_LOOP_XFER_SZ offsetof(WhereLoop,nLSlot)
  u16 nLSlot;           /* Number of slots allocated for aLTerm[] */
  WhereTerm **aLTerm;   /* WhereTerms used */
  WhereLoop *pNextLoop; /* Next WhereLoop object in the WhereClause */
  WhereTerm *aLTermSpace[4];  /* Initial aLTerm[] space */
};

/* Forward declaration of methods */
static int whereLoopResize(sqlite4*, WhereLoop*, int);

/*
** Each instance of this object holds a sequence of WhereLoop objects
** that implement some or all of a query plan.
**
** Think of each WhereLoop object as a node in a graph with arcs
** showing dependences and costs for travelling between nodes.  (That is
** not a completely accurate description because WhereLoop costs are a
** vector, not a scalar, and because dependences are many-to-one, not
** one-to-one as are graph nodes.  But it is a useful visualization aid.)
** Then a WherePath object is a path through the graph that visits some
** or all of the WhereLoop objects once.
**
** The "solver" works by creating the N best WherePath objects of length
** 1.  Then using those as a basis to compute the N best WherePath objects
** of length 2.  And so forth until the length of WherePaths equals the
** number of nodes in the FROM clause.  The best (lowest cost) WherePath
** at the end is the choosen query plan.
*/
struct WherePath {
  Bitmask maskLoop;     /* Bitmask of all WhereLoop objects in this path */
  Bitmask revLoop;      /* aLoop[]s that should be reversed for ORDER BY */
  WhereCost nRow;       /* Estimated number of rows generated by this path */
  WhereCost rCost;      /* Total cost of this path */
  u8 isOrdered;         /* True if this path satisfies ORDER BY */
  u8 isOrderedValid;    /* True if the isOrdered field is valid */
  WhereLoop **aLoop;    /* Array of WhereLoop objects implementing this path */
};

/*
** The query generator uses an array of instances of this structure to
** help it analyze the subexpressions of the WHERE clause.  Each WHERE
** clause subexpression is separated from the others by AND operators,
** usually, or sometimes subexpressions separated by OR.
**
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** bits in the Bitmask.  So, in the example above, the cursor numbers
** would be mapped into integers 0 through 7.
**
** The number of terms in a join is limited by the number of bits
** in prereqRight and prereqAll.  The default is 64 bits, hence SQLite
** is only able to process joins with 64 or fewer tables.
*/
typedef struct WhereTerm WhereTerm;
struct WhereTerm {
  Expr *pExpr;            /* Pointer to the subexpression that is this term */
  int iParent;            /* Disable pWC->a[iParent] when this term disabled */
  int leftCursor;         /* Cursor number of X in "X <op> <expr>" */
  union {
    int leftColumn;         /* Column number of X in "X <op> <expr>" */
    WhereOrInfo *pOrInfo;   /* Extra information if eOperator==WO_OR */
    WhereAndInfo *pAndInfo; /* Extra information if eOperator==WO_AND */
  } u;
  u16 eOperator;          /* A WO_xx value describing <op> */
  u8 wtFlags;             /* TERM_xxx bit flags.  See below */
  u8 nChild;              /* Number of children that must disable us */
  WhereClause *pWC;       /* The clause this term is part of */
  Bitmask prereqRight;    /* Bitmask of tables used by pExpr->pRight */
  Bitmask prereqAll;      /* Bitmask of tables referenced by pExpr */







<






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** bits in the Bitmask.  So, in the example above, the cursor numbers
** would be mapped into integers 0 through 7.
**
** The number of terms in a join is limited by the number of bits
** in prereqRight and prereqAll.  The default is 64 bits, hence SQLite
** is only able to process joins with 64 or fewer tables.
*/

struct WhereTerm {
  Expr *pExpr;            /* Pointer to the subexpression that is this term */
  int iParent;            /* Disable pWC->a[iParent] when this term disabled */
  int leftCursor;         /* Cursor number of X in "X <op> <expr>" */
  union {
    int leftColumn;         /* Column number of X in "X <op> <expr>" */
    WhereOrInfo *pOrInfo;   /* Extra information if (eOperator & WO_OR)!=0 */
    WhereAndInfo *pAndInfo; /* Extra information if (eOperator& WO_AND)!=0 */
  } u;
  u16 eOperator;          /* A WO_xx value describing <op> */
  u8 wtFlags;             /* TERM_xxx bit flags.  See below */
  u8 nChild;              /* Number of children that must disable us */
  WhereClause *pWC;       /* The clause this term is part of */
  Bitmask prereqRight;    /* Bitmask of tables used by pExpr->pRight */
  Bitmask prereqAll;      /* Bitmask of tables referenced by pExpr */
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#define TERM_OR_OK      0x40   /* Used during OR-clause processing */
#ifdef SQLITE4_ENABLE_STAT3
#  define TERM_VNULL    0x80   /* Manufactured x>NULL or x<=NULL term */
#else
#  define TERM_VNULL    0x00   /* Disabled if not using stat3 */
#endif

















/*
** An instance of the following structure holds all information about a
** WHERE clause.  Mostly this is a container for one or more WhereTerms.
**
** Explanation of pOuter:  For a WHERE clause of the form
**
**           a AND ((b AND c) OR (d AND e)) AND f
**
** There are separate WhereClause objects for the whole clause and for
** the subclauses "(b AND c)" and "(d AND e)".  The pOuter field of the
** subclauses points to the WhereClause object for the whole clause.
*/
struct WhereClause {
  Parse *pParse;           /* The parser context */
  WhereMaskSet *pMaskSet;  /* Mapping of table cursor numbers to bitmasks */
  Bitmask vmask;           /* Bitmask identifying virtual table cursors */
  WhereClause *pOuter;     /* Outer conjunction */
  u8 op;                   /* Split operator.  TK_AND or TK_OR */
  u16 wctrlFlags;          /* Might include WHERE_AND_ONLY */
  int nTerm;               /* Number of terms */
  int nSlot;               /* Number of entries in a[] */
  WhereTerm *a;            /* Each a[] describes a term of the WHERE cluase */
#if defined(SQLITE4_SMALL_STACK)
  WhereTerm aStatic[1];    /* Initial static space for a[] */
#else
  WhereTerm aStatic[8];    /* Initial static space for a[] */







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#define TERM_OR_OK      0x40   /* Used during OR-clause processing */
#ifdef SQLITE4_ENABLE_STAT3
#  define TERM_VNULL    0x80   /* Manufactured x>NULL or x<=NULL term */
#else
#  define TERM_VNULL    0x00   /* Disabled if not using stat3 */
#endif

/*
** An instance of the WhereScan object is used as an iterator for locating
** terms in the WHERE clause that are useful to the query planner.
*/
struct WhereScan {
  WhereClause *pOrigWC;      /* Original, innermost WhereClause */
  WhereClause *pWC;          /* WhereClause currently being scanned */
  char *zCollName;           /* Required collating sequence, if not NULL */
  char idxaff;               /* Must match this affinity, if zCollName!=NULL */
  unsigned char nEquiv;      /* Number of entries in aEquiv[] */
  unsigned char iEquiv;      /* Next unused slot in aEquiv[] */
  u32 opMask;                /* Acceptable operators */
  int k;                     /* Resume scanning at this->pWC->a[this->k] */
  int aEquiv[22];            /* Cursor,Column pairs for equivalence classes */
};

/*
** An instance of the following structure holds all information about a
** WHERE clause.  Mostly this is a container for one or more WhereTerms.
**
** Explanation of pOuter:  For a WHERE clause of the form
**
**           a AND ((b AND c) OR (d AND e)) AND f
**
** There are separate WhereClause objects for the whole clause and for
** the subclauses "(b AND c)" and "(d AND e)".  The pOuter field of the
** subclauses points to the WhereClause object for the whole clause.
*/
struct WhereClause {
  WhereInfo *pWInfo;       /* WHERE clause processing context */


  WhereClause *pOuter;     /* Outer conjunction */
  u8 op;                   /* Split operator.  TK_AND or TK_OR */

  int nTerm;               /* Number of terms */
  int nSlot;               /* Number of entries in a[] */
  WhereTerm *a;            /* Each a[] describes a term of the WHERE cluase */
#if defined(SQLITE4_SMALL_STACK)
  WhereTerm aStatic[1];    /* Initial static space for a[] */
#else
  WhereTerm aStatic[8];    /* Initial static space for a[] */
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};

/*
** An instance of the following structure keeps track of a mapping
** between VDBE cursor numbers and bits of the bitmasks in WhereTerm.
**
** The VDBE cursor numbers are small integers contained in 
** SrcList_item.iCursor and Expr.iTable fields.  For any given WHERE 
** clause, the cursor numbers might not begin with 0 and they might
** contain gaps in the numbering sequence.  But we want to make maximum
** use of the bits in our bitmasks.  This structure provides a mapping
** from the sparse cursor numbers into consecutive integers beginning
** with 0.
**
** If WhereMaskSet.ix[A]==B it means that The A-th bit of a Bitmask







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};

/*
** An instance of the following structure keeps track of a mapping
** between VDBE cursor numbers and bits of the bitmasks in WhereTerm.
**
** The VDBE cursor numbers are small integers contained in 
** SrcListItem.iCursor and Expr.iTable fields.  For any given WHERE 
** clause, the cursor numbers might not begin with 0 and they might
** contain gaps in the numbering sequence.  But we want to make maximum
** use of the bits in our bitmasks.  This structure provides a mapping
** from the sparse cursor numbers into consecutive integers beginning
** with 0.
**
** If WhereMaskSet.ix[A]==B it means that The A-th bit of a Bitmask
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*/
struct WhereMaskSet {
  int n;                        /* Number of assigned cursor values */
  int ix[BMS];                  /* Cursor assigned to each bit */
};

/*



** A WhereCost object records a lookup strategy and the estimated






** cost of pursuing that strategy.









*/
struct WhereCost {


  WherePlan plan;    /* The lookup strategy */





  double rCost;      /* Overall cost of pursuing this search strategy */







  Bitmask used;      /* Bitmask of cursors used by this plan */



};

/*
** Bitmasks for the operators that indices are able to exploit.  An

** OR-ed combination of these values can be used when searching for
** terms in the where clause.
*/
#define WO_IN     0x001
#define WO_EQ     0x002
#define WO_LT     (WO_EQ<<(TK_LT-TK_EQ))
#define WO_LE     (WO_EQ<<(TK_LE-TK_EQ))
#define WO_GT     (WO_EQ<<(TK_GT-TK_EQ))
#define WO_GE     (WO_EQ<<(TK_GE-TK_EQ))
#define WO_MATCH  0x040
#define WO_ISNULL 0x080
#define WO_OR     0x100       /* Two or more OR-connected terms */
#define WO_AND    0x200       /* Two or more AND-connected terms */

#define WO_NOOP   0x800       /* This term does not restrict search space */

#define WO_ALL    0xfff       /* Mask of all possible WO_* values */
#define WO_SINGLE 0x0ff       /* Mask of all non-compound WO_* values */

/*
** Value for wsFlags returned by bestIndex() and stored in
** WhereLevel.wsFlags.  These flags determine which search
** strategies are appropriate.
**
** The least significant 12 bits is reserved as a mask for WO_ values above.
** The WhereLevel.wsFlags field is usually set to WO_IN|WO_EQ|WO_ISNULL.
** But if the table is the right table of a left join, WhereLevel.wsFlags
** is set to WO_IN|WO_EQ.  The WhereLevel.wsFlags field can then be used as
** the "op" parameter to findTerm when we are resolving equality constraints.
** ISNULL constraints will then not be used on the right table of a left
** join.  Tickets #2177 and #2189.
*/
#define WHERE_COLUMN_EQ    0x00010000  /* x=EXPR or x IN (...) or x IS NULL */
#define WHERE_COLUMN_RANGE 0x00020000  /* x<EXPR and/or x>EXPR */
#define WHERE_COLUMN_IN    0x00040000  /* x IN (...) */
#define WHERE_COLUMN_NULL  0x00080000  /* x IS NULL */






#define WHERE_INDEXED      0x000f0000  /* Anything that uses an index */
#define WHERE_NOT_FULLSCAN 0x100f3000  /* Does not do a full table scan */
#define WHERE_IN_ABLE      0x000f1000  /* Able to support an IN operator */



#define WHERE_TOP_LIMIT    0x00100000  /* x<EXPR or x<=EXPR constraint */
#define WHERE_BTM_LIMIT    0x00200000  /* x>EXPR or x>=EXPR constraint */





















#define WHERE_BOTH_LIMIT   0x00300000  /* Both x>EXPR and x<EXPR */
#define WHERE_IDX_ONLY     0x00800000  /* Use index only - omit table */
#define WHERE_ORDERBY      0x01000000  /* Output will appear in correct order */
#define WHERE_REVERSE      0x02000000  /* Scan in reverse order */



#define WHERE_UNIQUE       0x04000000  /* Selects no more than one row */







#define WHERE_VIRTUALTABLE 0x08000000  /* Use virtual-table processing */







#define WHERE_MULTI_OR     0x10000000  /* OR using multiple indices */


#define WHERE_TEMP_INDEX   0x20000000  /* Uses an ephemeral index */




#define WHERE_DISTINCT     0x40000000  /* Correct order for DISTINCT */









/*
** Initialize a preallocated WhereClause structure.
*/
static void whereClauseInit(
  WhereClause *pWC,        /* The WhereClause to be initialized */
  Parse *pParse,           /* The parsing context */
  WhereMaskSet *pMaskSet,  /* Mapping from table cursor numbers to bitmasks */
  u16 wctrlFlags           /* Might include WHERE_AND_ONLY */
){
  pWC->pParse = pParse;
  pWC->pMaskSet = pMaskSet;
  pWC->pOuter = 0;
  pWC->nTerm = 0;
  pWC->nSlot = ArraySize(pWC->aStatic);
  pWC->a = pWC->aStatic;
  pWC->vmask = 0;
  pWC->wctrlFlags = wctrlFlags;
}

/* Forward reference */
static void whereClauseClear(WhereClause*);

/*
** Deallocate all memory associated with a WhereOrInfo object.







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*/
struct WhereMaskSet {
  int n;                        /* Number of assigned cursor values */
  int ix[BMS];                  /* Cursor assigned to each bit */
};

/*
** This object is a convenience wrapper holding all information needed
** to construct WhereLoop objects for a particular query.
*/
struct WhereLoopBuilder {
  WhereInfo *pWInfo;        /* Information about this WHERE */
  WhereClause *pWC;         /* WHERE clause terms */
  ExprList *pOrderBy;       /* ORDER BY clause */
  WhereLoop *pNew;          /* Template WhereLoop */
  WhereLoop *pBest;         /* If non-NULL, store single best loop here */
};

/*
** The WHERE clause processing routine has two halves.  The
** first part does the start of the WHERE loop and the second
** half does the tail of the WHERE loop.  An instance of
** this structure is returned by the first half and passed
** into the second half to give some continuity.
**
** An instance of this object holds the complete state of the query
** planner.
*/
struct WhereInfo {
  Parse *pParse;            /* Parsing and code generating context */
  SrcList *pTabList;        /* List of tables in the join */
  ExprList *pOrderBy;       /* The ORDER BY clause or NULL */
  ExprList *pResultSet;     /* Result set. DISTINCT operates on these */
  WhereLoop *pLoops;        /* List of all WhereLoop objects */
  Bitmask revMask;          /* Mask of ORDER BY terms that need reversing */
  WhereCost nRowOut;        /* Estimated number of output rows */
  u16 wctrlFlags;           /* Flags originally passed to sqlite4WhereBegin() */
  u8 bOBSat;                /* ORDER BY satisfied by indices */
  u8 okOnePass;             /* Ok to use one-pass algorithm for UPDATE/DELETE */
  u8 untestedTerms;         /* Not all WHERE terms resolved by outer loop */
  u8 eDistinct;             /* One of the WHERE_DISTINCT_* values below */
  u8 nLevel;                /* Number of nested loop */
  int iTop;                 /* The very beginning of the WHERE loop */
  int iContinue;            /* Jump here to continue with next record */
  int iBreak;               /* Jump here to break out of the loop */
  int savedNQueryLoop;      /* pParse->nQueryLoop outside the WHERE loop */
  WhereMaskSet sMaskSet;    /* Map cursor numbers to bitmasks */
  WhereClause sWC;          /* Decomposition of the WHERE clause */
  WhereLevel a[1];          /* Information about each nest loop in WHERE */
};

/*
** Bitmasks for the operators on WhereTerm objects.  These are all
** operators that are of interest to the query planner.  An
** OR-ed combination of these values can be used when searching for
** particular WhereTerms within a WhereClause.
*/
#define WO_IN     0x001
#define WO_EQ     0x002
#define WO_LT     (WO_EQ<<(TK_LT-TK_EQ))
#define WO_LE     (WO_EQ<<(TK_LE-TK_EQ))
#define WO_GT     (WO_EQ<<(TK_GT-TK_EQ))
#define WO_GE     (WO_EQ<<(TK_GE-TK_EQ))
#define WO_MATCH  0x040
#define WO_ISNULL 0x080
#define WO_OR     0x100       /* Two or more OR-connected terms */
#define WO_AND    0x200       /* Two or more AND-connected terms */
#define WO_EQUIV  0x400       /* Of the form A==B, both columns */
#define WO_NOOP   0x800       /* This term does not restrict search space */

#define WO_ALL    0xfff       /* Mask of all possible WO_* values */
#define WO_SINGLE 0x0ff       /* Mask of all non-compound WO_* values */

/*
** These are definitions of bits in the WhereLoop.wsFlags field.
** The particular combination of bits in each WhereLoop help to



** determine the algorithm that WhereLoop represents.





*/
#define WHERE_COLUMN_EQ    0x00000001  /* x=EXPR */
#define WHERE_COLUMN_RANGE 0x00000002  /* x<EXPR and/or x>EXPR */
#define WHERE_COLUMN_IN    0x00000004  /* x IN (...) */
#define WHERE_COLUMN_NULL  0x00000008  /* x IS NULL */
#define WHERE_CONSTRAINT   0x0000000f  /* Any of the WHERE_COLUMN_xxx values */
#define WHERE_TOP_LIMIT    0x00000010  /* x<EXPR or x<=EXPR constraint */
#define WHERE_BTM_LIMIT    0x00000020  /* x>EXPR or x>=EXPR constraint */
#define WHERE_BOTH_LIMIT   0x00000030  /* Both x>EXPR and x<EXPR */
#define WHERE_IDX_ONLY     0x00000040  /* Use index only - omit table */
#define WHERE_IPK          0x00000100  /* x is the INTEGER PRIMARY KEY */
#define WHERE_INDEXED      0x00000200  /* WhereLoop.u.btree.pIndex is valid */
#define WHERE_VIRTUALTABLE 0x00000400  /* WhereLoop.u.vtab is valid */
#define WHERE_IN_ABLE      0x00000800  /* Able to support an IN operator */
#define WHERE_ONEROW       0x00001000  /* Selects no more than one row */
#define WHERE_MULTI_OR     0x00002000  /* OR using multiple indices */
#define WHERE_AUTO_INDEX   0x00004000  /* Uses an ephemeral index */


/* Convert a WhereCost value (10 times log2(X)) into its integer value X.
** A rough approximation is used.  The value returned is not exact.
*/
static u64 whereCostToInt(WhereCost x){
  u64 n;
  if( x<10 ) return 1;
  n = x%10;
  x /= 10;
  if( n>=5 ) n -= 2;
  else if( n>=1 ) n -= 1;
  if( x>=3 ) return (n+8)<<(x-3);
  return (n+8)>>(3-x);
}

/*
** Return the estimated number of output rows from a WHERE clause
*/
u64 sqlite4WhereOutputRowCount(WhereInfo *pWInfo){
  return whereCostToInt(pWInfo->nRowOut);
}

/*
** Return one of the WHERE_DISTINCT_xxxxx values to indicate how this
** WHERE clause returns outputs for DISTINCT processing.
*/
int sqlite4WhereIsDistinct(WhereInfo *pWInfo){
  return pWInfo->eDistinct;
}

/*
** Return TRUE if the WHERE clause returns rows in ORDER BY order.
** Return FALSE if the output needs to be sorted.
*/
int sqlite4WhereIsOrdered(WhereInfo *pWInfo){
  return pWInfo->bOBSat!=0;
}

/*
** Return the VDBE address or label to jump to in order to continue
** immediately with the next row of a WHERE clause.
*/
int sqlite4WhereContinueLabel(WhereInfo *pWInfo){
  return pWInfo->iContinue;
}

/*
** Return the VDBE address or label to jump to in order to break
** out of a WHERE loop.
*/
int sqlite4WhereBreakLabel(WhereInfo *pWInfo){
  return pWInfo->iBreak;
}

/*
** Return TRUE if an UPDATE or DELETE statement can operate directly on
** the rowids returned by a WHERE clause.  Return FALSE if doing an
** UPDATE or DELETE might change subsequent WHERE clause results.
*/
int sqlite4WhereOkOnePass(WhereInfo *pWInfo){
  return pWInfo->okOnePass;
}

/*
** Initialize a preallocated WhereClause structure.
*/
static void whereClauseInit(
  WhereClause *pWC,        /* The WhereClause to be initialized */
  WhereInfo *pWInfo        /* The WHERE processing context */


){
  pWC->pWInfo = pWInfo;

  pWC->pOuter = 0;
  pWC->nTerm = 0;
  pWC->nSlot = ArraySize(pWC->aStatic);
  pWC->a = pWC->aStatic;


}

/* Forward reference */
static void whereClauseClear(WhereClause*);

/*
** Deallocate all memory associated with a WhereOrInfo object.
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/*
** Deallocate a WhereClause structure.  The WhereClause structure
** itself is not freed.  This routine is the inverse of whereClauseInit().
*/
static void whereClauseClear(WhereClause *pWC){
  int i;
  WhereTerm *a;
  sqlite4 *db = pWC->pParse->db;
  for(i=pWC->nTerm-1, a=pWC->a; i>=0; i--, a++){
    if( a->wtFlags & TERM_DYNAMIC ){
      sqlite4ExprDelete(db, a->pExpr);
    }
    if( a->wtFlags & TERM_ORINFO ){
      whereOrInfoDelete(db, a->u.pOrInfo);
    }else if( a->wtFlags & TERM_ANDINFO ){
      whereAndInfoDelete(db, a->u.pAndInfo);
    }
  }
  if( pWC->a!=pWC->aStatic ){
    sqlite4DbFree(db, pWC->a);
  }
}




















/*
** Add a single new WhereTerm entry to the WhereClause object pWC.
** The new WhereTerm object is constructed from Expr p and with wtFlags.
** The index in pWC->a[] of the new WhereTerm is returned on success.
** 0 is returned if the new WhereTerm could not be added due to a memory
** allocation error.  The memory allocation failure will be recorded in







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/*
** Deallocate a WhereClause structure.  The WhereClause structure
** itself is not freed.  This routine is the inverse of whereClauseInit().
*/
static void whereClauseClear(WhereClause *pWC){
  int i;
  WhereTerm *a;
  sqlite4 *db = pWC->pWInfo->pParse->db;
  for(i=pWC->nTerm-1, a=pWC->a; i>=0; i--, a++){
    if( a->wtFlags & TERM_DYNAMIC ){
      sqlite4ExprDelete(db, a->pExpr);
    }
    if( a->wtFlags & TERM_ORINFO ){
      whereOrInfoDelete(db, a->u.pOrInfo);
    }else if( a->wtFlags & TERM_ANDINFO ){
      whereAndInfoDelete(db, a->u.pAndInfo);
    }
  }
  if( pWC->a!=pWC->aStatic ){
    sqlite4DbFree(db, pWC->a);
  }
}


/*
** Skip over any TK_COLLATE and/or TK_AS operators at the root of
** an expression.
*/
Expr *sqlite4ExprSkipCollate(Expr *pExpr){
  while( pExpr && (pExpr->op==TK_COLLATE || pExpr->op==TK_AS) ){
    pExpr = pExpr->pLeft;
  }
  return pExpr;
}

/*
** A bit in a Bitmask
*/
#define MASKBIT(n)   (((Bitmask)1)<<(n))



/*
** Add a single new WhereTerm entry to the WhereClause object pWC.
** The new WhereTerm object is constructed from Expr p and with wtFlags.
** The index in pWC->a[] of the new WhereTerm is returned on success.
** 0 is returned if the new WhereTerm could not be added due to a memory
** allocation error.  The memory allocation failure will be recorded in
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static int whereClauseInsert(WhereClause *pWC, Expr *p, u8 wtFlags){
  WhereTerm *pTerm;
  int idx;
  testcase( wtFlags & TERM_VIRTUAL );  /* EV: R-00211-15100 */
  if( pWC->nTerm>=pWC->nSlot ){
    WhereTerm *pOld = pWC->a;
    sqlite4 *db = pWC->pParse->db;
    pWC->a = sqlite4DbMallocRaw(db, sizeof(pWC->a[0])*pWC->nSlot*2 );
    if( pWC->a==0 ){
      if( wtFlags & TERM_DYNAMIC ){
        sqlite4ExprDelete(db, p);
      }
      pWC->a = pOld;
      return 0;
    }
    memcpy(pWC->a, pOld, sizeof(pWC->a[0])*pWC->nTerm);
    if( pOld!=pWC->aStatic ){
      sqlite4DbFree(db, pOld);
    }
    pWC->nSlot = sqlite4DbMallocSize(db, pWC->a)/sizeof(pWC->a[0]);
  }
  pTerm = &pWC->a[idx = pWC->nTerm++];
  pTerm->pExpr = p;
  pTerm->wtFlags = wtFlags;
  pTerm->pWC = pWC;
  pTerm->iParent = -1;
  return idx;
}

/*







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static int whereClauseInsert(WhereClause *pWC, Expr *p, u8 wtFlags){
  WhereTerm *pTerm;
  int idx;
  testcase( wtFlags & TERM_VIRTUAL );  /* EV: R-00211-15100 */
  if( pWC->nTerm>=pWC->nSlot ){
    WhereTerm *pOld = pWC->a;
    sqlite4 *db = pWC->pWInfo->pParse->db;
    pWC->a = sqlite4DbMallocRaw(db, sizeof(pWC->a[0])*pWC->nSlot*2 );
    if( pWC->a==0 ){
      if( wtFlags & TERM_DYNAMIC ){
        sqlite4ExprDelete(db, p);
      }
      pWC->a = pOld;
      return 0;
    }
    memcpy(pWC->a, pOld, sizeof(pWC->a[0])*pWC->nTerm);
    if( pOld!=pWC->aStatic ){
      sqlite4DbFree(db, pOld);
    }
    pWC->nSlot = sqlite4DbMallocSize(db, pWC->a)/sizeof(pWC->a[0]);
  }
  pTerm = &pWC->a[idx = pWC->nTerm++];
  pTerm->pExpr = sqlite4ExprSkipCollate(p);
  pTerm->wtFlags = wtFlags;
  pTerm->pWC = pWC;
  pTerm->iParent = -1;
  return idx;
}

/*
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** The original WHERE clause in pExpr is unaltered.  All this routine
** does is make slot[] entries point to substructure within pExpr.
**
** In the previous sentence and in the diagram, "slot[]" refers to
** the WhereClause.a[] array.  The slot[] array grows as needed to contain
** all terms of the WHERE clause.
*/
static void whereSplit(WhereClause *pWC, Expr *pExpr, int op){
  pWC->op = (u8)op;
  if( pExpr==0 ) return;
  if( pExpr->op!=op ){
    whereClauseInsert(pWC, pExpr, 0);
  }else{
    whereSplit(pWC, pExpr->pLeft, op);
    whereSplit(pWC, pExpr->pRight, op);
  }
}

/*
** Initialize an expression mask set (a WhereMaskSet object)
*/
#define initMaskSet(P)  memset(P, 0, sizeof(*P))

/*
** Return the bitmask for the given cursor number.  Return 0 if
** iCursor is not in the set.
*/
static Bitmask getMask(WhereMaskSet *pMaskSet, int iCursor){
  int i;
  assert( pMaskSet->n<=(int)sizeof(Bitmask)*8 );
  for(i=0; i<pMaskSet->n; i++){
    if( pMaskSet->ix[i]==iCursor ){
      return ((Bitmask)1)<<i;
    }
  }
  return 0;
}

/*
** Create a new mask for cursor iCursor.
**
** There is one cursor per table in the FROM clause.  The number of
** tables in the FROM clause is limited by a test early in the
** sqlite4WhereBegin() routine.  So we know that the pMaskSet->ix[]
** array will never overflow.
*/
static void createMask(WhereMaskSet *pMaskSet, int iCursor){
  assert( pMaskSet->n < ArraySize(pMaskSet->ix) );
  pMaskSet->ix[pMaskSet->n++] = iCursor;
}

/*
** This routine walks (recursively) an expression tree and generates
** a bitmask indicating which tables are used in that expression
** tree.
**
** In order for this routine to work, the calling function must have
** previously invoked sqlite4ResolveExprNames() on the expression.  See
** the header comment on that routine for additional information.
** The sqlite4ResolveExprNames() routines looks for column names and
** sets their opcodes to TK_COLUMN and their Expr.iTable fields to
** the VDBE cursor number of the table.  This routine just has to
** translate the cursor numbers into bitmask values and OR all
** the bitmasks together.
*/
static Bitmask exprListTableUsage(WhereMaskSet*, ExprList*);
static Bitmask exprSelectTableUsage(WhereMaskSet*, Select*);
static Bitmask exprTableUsage(WhereMaskSet *pMaskSet, Expr *p){
  Bitmask mask = 0;
  if( p==0 ) return 0;
  if( p->op==TK_COLUMN ){







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** The original WHERE clause in pExpr is unaltered.  All this routine
** does is make slot[] entries point to substructure within pExpr.
**
** In the previous sentence and in the diagram, "slot[]" refers to
** the WhereClause.a[] array.  The slot[] array grows as needed to contain
** all terms of the WHERE clause.
*/
static void whereSplit(WhereClause *pWC, Expr *pExpr, u8 op){
  pWC->op = op;
  if( pExpr==0 ) return;
  if( pExpr->op!=op ){
    whereClauseInsert(pWC, pExpr, 0);
  }else{
    whereSplit(pWC, pExpr->pLeft, op);
    whereSplit(pWC, pExpr->pRight, op);
  }
}

/*
** Initialize a WhereMaskSet object
*/
#define initMaskSet(P)  (P)->n=0

/*
** Return the bitmask for the given cursor number.  Return 0 if
** iCursor is not in the set.
*/
static Bitmask getMask(WhereMaskSet *pMaskSet, int iCursor){
  int i;
  assert( pMaskSet->n<=(int)sizeof(Bitmask)*8 );
  for(i=0; i<pMaskSet->n; i++){
    if( pMaskSet->ix[i]==iCursor ){
      return MASKBIT(i);
    }
  }
  return 0;
}

/*
** Create a new mask for cursor iCursor.
**
** There is one cursor per table in the FROM clause.  The number of
** tables in the FROM clause is limited by a test early in the
** sqlite4WhereBegin() routine.  So we know that the pMaskSet->ix[]
** array will never overflow.
*/
static void createMask(WhereMaskSet *pMaskSet, int iCursor){
  assert( pMaskSet->n < ArraySize(pMaskSet->ix) );
  pMaskSet->ix[pMaskSet->n++] = iCursor;
}

/*
** These routine walk (recursively) an expression tree and generates
** a bitmask indicating which tables are used in that expression
** tree.









*/
static Bitmask exprListTableUsage(WhereMaskSet*, ExprList*);
static Bitmask exprSelectTableUsage(WhereMaskSet*, Select*);
static Bitmask exprTableUsage(WhereMaskSet *pMaskSet, Expr *p){
  Bitmask mask = 0;
  if( p==0 ) return 0;
  if( p->op==TK_COLUMN ){
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  }
  return mask;
}

/*
** Return TRUE if the given operator is one of the operators that is
** allowed for an indexable WHERE clause term.  The allowed operators are
** "=", "<", ">", "<=", ">=", and "IN".
**
** IMPLEMENTATION-OF: R-59926-26393 To be usable by an index a term must be
** of one of the following forms: column = expression column > expression
** column >= expression column < expression column <= expression
** expression = column expression > column expression >= column
** expression < column expression <= column column IN
** (expression-list) column IN (subquery) column IS NULL







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  }
  return mask;
}

/*
** Return TRUE if the given operator is one of the operators that is
** allowed for an indexable WHERE clause term.  The allowed operators are
** "=", "<", ">", "<=", ">=", "IN", and "IS NULL"
**
** IMPLEMENTATION-OF: R-59926-26393 To be usable by an index a term must be
** of one of the following forms: column = expression column > expression
** column >= expression column < expression column <= expression
** expression = column expression > column expression >= column
** expression < column expression <= column column IN
** (expression-list) column IN (subquery) column IS NULL
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*/
#define SWAP(TYPE,A,B) {TYPE t=A; A=B; B=t;}

/*
** Commute a comparison operator.  Expressions of the form "X op Y"
** are converted into "Y op X".
**

** If a collation sequence is associated with either the left or right
** side of the comparison, it remains associated with the same side after
** the commutation. So "Y collate NOCASE op X" becomes 
** "X collate NOCASE op Y". This is because any collation sequence on
** the left hand side of a comparison overrides any collation sequence 
** attached to the right. For the same reason the EP_ExpCollate flag
** is not commuted.
*/
static void exprCommute(Parse *pParse, Expr *pExpr){
  u16 expRight = (pExpr->pRight->flags & EP_ExpCollate);
  u16 expLeft = (pExpr->pLeft->flags & EP_ExpCollate);
  assert( allowedOp(pExpr->op) && pExpr->op!=TK_IN );





  pExpr->pRight->pColl = sqlite4ExprCollSeq(pParse, pExpr->pRight);
  pExpr->pLeft->pColl = sqlite4ExprCollSeq(pParse, pExpr->pLeft);
  SWAP(CollSeq*,pExpr->pRight->pColl,pExpr->pLeft->pColl);

  pExpr->pRight->flags = (pExpr->pRight->flags & ~EP_ExpCollate) | expLeft;

  pExpr->pLeft->flags = (pExpr->pLeft->flags & ~EP_ExpCollate) | expRight;


  SWAP(Expr*,pExpr->pRight,pExpr->pLeft);
  if( pExpr->op>=TK_GT ){
    assert( TK_LT==TK_GT+2 );
    assert( TK_GE==TK_LE+2 );
    assert( TK_GT>TK_EQ );
    assert( TK_GT<TK_LE );
    assert( pExpr->op>=TK_GT && pExpr->op<=TK_GE );







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#define SWAP(TYPE,A,B) {TYPE t=A; A=B; B=t;}

/*
** Commute a comparison operator.  Expressions of the form "X op Y"
** are converted into "Y op X".
**
** If left/right precedence rules come into play when determining the
** collating sequence, then COLLATE operators are adjusted to ensure
** that the collating sequence does not change.  For example:
** "Y collate NOCASE op X" becomes "X op Y" because any collation sequence on

** the left hand side of a comparison overrides any collation sequence 
** attached to the right. For the same reason the EP_ExpCollate flag
** is not commuted.
*/
static void exprCommute(Parse *pParse, Expr *pExpr){
  u16 expRight = (pExpr->pRight->flags & EP_ExpCollate);
  u16 expLeft = (pExpr->pLeft->flags & EP_ExpCollate);
  assert( allowedOp(pExpr->op) && pExpr->op!=TK_IN );
  if( expRight==expLeft ){
    /* Either X and Y both have COLLATE operator or neither do */
    if( expRight ){
      /* Both X and Y have COLLATE operators.  Make sure X is always
      ** used by clearing the EP_ExpCollate flag from Y. */
      pExpr->pRight->flags &= ~EP_ExpCollate;
    }else if( sqlite4ExprCollSeq(pParse, pExpr->pLeft)!=0 ){

      /* Neither X nor Y have COLLATE operators, but X has a non-default
      ** collating sequence.  So add the EP_ExpCollate marker on X to cause
      ** it to be searched first. */
      pExpr->pLeft->flags |= EP_ExpCollate;
    }
  }
  SWAP(Expr*,pExpr->pRight,pExpr->pLeft);
  if( pExpr->op>=TK_GT ){
    assert( TK_LT==TK_GT+2 );
    assert( TK_GE==TK_LE+2 );
    assert( TK_GT>TK_EQ );
    assert( TK_GT<TK_LE );
    assert( pExpr->op>=TK_GT && pExpr->op<=TK_GE );
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  assert( op!=TK_EQ || c==WO_EQ );
  assert( op!=TK_LT || c==WO_LT );
  assert( op!=TK_LE || c==WO_LE );
  assert( op!=TK_GT || c==WO_GT );
  assert( op!=TK_GE || c==WO_GE );
  return c;
}


























































































































































































/*
** Search for a term in the WHERE clause that is of the form "X <op> <expr>"
** where X is a reference to the iColumn of table iCur and <op> is one of
** the WO_xx operator codes specified by the op parameter.
** Return a pointer to the term.  Return 0 if not found.

















*/
static WhereTerm *findTerm(
  WhereClause *pWC,     /* The WHERE clause to be searched */
  int iCur,             /* Cursor number of LHS */
  int iColumn,          /* Column number of LHS */
  Bitmask notReady,     /* RHS must not overlap with this mask */
  u32 op,               /* Mask of WO_xx values describing operator */
  Index *pIdx           /* Must be compatible with this index, if not NULL */
){
  sqlite4 *db = pWC->pParse->db;  /* Database handle */
  WhereTerm *pTerm;
  int k;

  assert( iCur>=0 );
  op &= WO_ALL;
  for(; pWC; pWC=pWC->pOuter){
    for(pTerm=pWC->a, k=pWC->nTerm; k; k--, pTerm++){
      if( pTerm->leftCursor==iCur
         && (pTerm->prereqRight & notReady)==0
         && pTerm->u.leftColumn==iColumn
         && (pTerm->eOperator & op)!=0
      ){
        if( iColumn>=0 && pIdx && pTerm->eOperator!=WO_ISNULL ){
          Table *pTab = pIdx->pTable;
          const char *zColl;      /* Collation sequence used by index */
          CollSeq *pColl;         /* Collation sequence used by expression */
          Expr *pX = pTerm->pExpr;
          int j;
          Parse *pParse = pWC->pParse;
  
          if( !sqlite4IndexAffinityOk(pX, pTab->aCol[iColumn].affinity) ){
            continue;
          }
  
          /* Figure out the collation sequence used by expression pX. Store
          ** this in pColl. Also the collation sequence used by the index.
          ** Store this one in zColl.  */
          assert(pX->pLeft);
          pColl = sqlite4BinaryCompareCollSeq(pParse, pX->pLeft, pX->pRight);
          for(j=0; pIdx->aiColumn[j]!=iColumn && j<pIdx->nColumn; j++);
          if( j>=pIdx->nColumn ){
            zColl = pTab->aCol[iColumn].zColl;
          }else{
            zColl = pIdx->azColl[j];
          }

          /* If the collation sequence used by the index is not the same as
          ** that used by the expression, then this term is not a match.  */
          if( pColl!=sqlite4FindCollSeq(db, zColl, 0) ) continue;
        }
        return pTerm;
      }

    }

  }
  return 0;
}

/* Forward reference */
static void exprAnalyze(SrcList*, WhereClause*, int);

/*
** Call exprAnalyze on all terms in a WHERE clause.  
**
** Note that exprAnalyze() might add new virtual terms onto the end of 
** the WHERE clause.  We do not want to analyze these virtual terms, so 
** start analyzing at the end and work forward so that the added virtual 
** terms are never processed.
*/
static void exprAnalyzeAll(
  SrcList *pTabList,       /* the FROM clause */
  WhereClause *pWC         /* the WHERE clause to be analyzed */
){
  int i;
  for(i=pWC->nTerm-1; i>=0; i--){







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  assert( op!=TK_EQ || c==WO_EQ );
  assert( op!=TK_LT || c==WO_LT );
  assert( op!=TK_LE || c==WO_LE );
  assert( op!=TK_GT || c==WO_GT );
  assert( op!=TK_GE || c==WO_GE );
  return c;
}

/*
** Advance to the next WhereTerm that matches according to the criteria
** established when the pScan object was initialized by whereScanInit().
** Return NULL if there are no more matching WhereTerms.
*/
static WhereTerm *whereScanNext(WhereScan *pScan){
  int iCur;            /* The cursor on the LHS of the term */
  int iColumn;         /* The column on the LHS of the term.  -1 for IPK */
  Expr *pX;            /* An expression being tested */
  WhereClause *pWC;    /* Shorthand for pScan->pWC */
  WhereTerm *pTerm;    /* The term being tested */
  int k = pScan->k;    /* Where to start scanning */

  while( pScan->iEquiv<=pScan->nEquiv ){
    iCur = pScan->aEquiv[pScan->iEquiv-2];
    iColumn = pScan->aEquiv[pScan->iEquiv-1];
    while( (pWC = pScan->pWC)!=0 ){
      for(pTerm=pWC->a+k; k<pWC->nTerm; k++, pTerm++){
        if( pTerm->leftCursor==iCur && pTerm->u.leftColumn==iColumn ){
          if( (pTerm->eOperator & WO_EQUIV)!=0
           && pScan->nEquiv<ArraySize(pScan->aEquiv)
          ){
            int j;
            pX = sqlite4ExprSkipCollate(pTerm->pExpr->pRight);
            assert( pX->op==TK_COLUMN );
            for(j=0; j<pScan->nEquiv; j+=2){
              if( pScan->aEquiv[j]==pX->iTable
               && pScan->aEquiv[j+1]==pX->iColumn ){
                  break;
              }
            }
            if( j==pScan->nEquiv ){
              pScan->aEquiv[j] = pX->iTable;
              pScan->aEquiv[j+1] = pX->iColumn;
              pScan->nEquiv += 2;
            }
          }
          if( (pTerm->eOperator & pScan->opMask)!=0 ){
            /* Verify the affinity and collating sequence match */
            if( pScan->zCollName && (pTerm->eOperator & WO_ISNULL)==0 ){
              CollSeq *pColl;
              Parse *pParse = pWC->pWInfo->pParse;
              pX = pTerm->pExpr;
              if( !sqlite4IndexAffinityOk(pX, pScan->idxaff) ){
                continue;
              }
              assert(pX->pLeft);
              pColl = sqlite4BinaryCompareCollSeq(pParse,
                                                  pX->pLeft, pX->pRight);
              if( pColl==0 ) pColl = pParse->db->pDfltColl;
              if( sqlite4_stricmp(pColl->zName, pScan->zCollName) ){
                continue;
              }
            }
            if( (pTerm->eOperator & WO_EQ)!=0
             && (pX = pTerm->pExpr->pRight)->op==TK_COLUMN
             && pX->iTable==pScan->aEquiv[0]
             && pX->iColumn==pScan->aEquiv[1]
            ){
              continue;
            }
            pScan->k = k+1;
            return pTerm;
          }
        }
      }
      pScan->pWC = pScan->pWC->pOuter;
      k = 0;
    }
    pScan->pWC = pScan->pOrigWC;
    k = 0;
    pScan->iEquiv += 2;
  }
  return 0;
}

/*
** Return the table column number of the iIdxCol'th field in the index
** keys used by index pIdx, including any appended PRIMARY KEY fields.
** If there is no iIdxCol'th field in index pIdx, return -2.
**
** Example:
**
**   CREATE TABLE t1(a, b, c, PRIMARY KEY(a, b));
**   CREATE INDEX i1 ON t1(c);
**
** Index i1 in the example above consists of three fields - the indexed
** field "c" followed by the two primary key fields. The automatic PRIMARY
** KEY index consists of two fields only.
*/
static int idxColumnNumber(Index *pIdx, Index *pPk, int iIdxCol){
  int iRet = -2;
  if( iIdxCol<pIdx->nColumn ){
    iRet = pIdx->aiColumn[iIdxCol];
  }else if( pPk && iIdxCol<(pIdx->nColumn + pPk->nColumn) ){
    iRet = pPk->aiColumn[iIdxCol - pIdx->nColumn];
  }
  return iRet;
}

/*
** Return a pointer to a buffer containing the name of the collation 
** sequence used with the iIdxCol'th field in index pIdx, including any
** appended PRIMARY KEY fields.
*/
static char *idxColumnCollation(Index *pIdx, Index *pPk, int iIdxCol){
  char *zColl;
  assert( iIdxCol<(pIdx->nColumn + pPk->nColumn) );
  if( iIdxCol<pIdx->nColumn ){
    zColl = pIdx->azColl[iIdxCol];
  }else if( pPk && iIdxCol<(pIdx->nColumn + pPk->nColumn) ){
    zColl = pPk->azColl[iIdxCol - pIdx->nColumn];
  }
  return zColl;
}

/*
** Return the sort order (SQLITE4_SO_ASC or DESC) used by the iIdxCol'th 
** field in index pIdx, including any appended PRIMARY KEY fields.
*/
static int idxColumnSortOrder(Index *pIdx, Index *pPk, int iIdxCol){
  int iRet = SQLITE4_SO_ASC;
  if( iIdxCol<pIdx->nColumn ){
    iRet = pIdx->aSortOrder[iIdxCol];
  }
  return iRet;
}

/*
** Return the total number of fields in the index pIdx, including any
** trailing primary key fields.
*/
static int idxColumnCount(Index *pIdx, Index *pPk){
  return (pIdx->nColumn + (pIdx==pPk ? 0 : pPk->nColumn));
}

/*
** Initialize a WHERE clause scanner object.  Return a pointer to the
** first match.  Return NULL if there are no matches.
**
** The scanner will be searching the WHERE clause pWC.  It will look
** for terms of the form "X <op> <expr>" where X is column iColumn of table
** iCur.  The <op> must be one of the operators described by opMask.
**
** If the search is for X and the WHERE clause contains terms of the
** form X=Y then this routine might also return terms of the form
** "Y <op> <expr>".  The number of levels of transitivity is limited,
** but is enough to handle most commonly occurring SQL statements.
**
** If X is not the INTEGER PRIMARY KEY then X must be compatible with
** index pIdx.
*/
static WhereTerm *whereScanInit(
  WhereScan *pScan,       /* The WhereScan object being initialized */
  WhereClause *pWC,       /* The WHERE clause to be scanned */
  int iCur,               /* Cursor to scan for */
  int iColumn,            /* Column to scan for */
  u32 opMask,             /* Operator(s) to scan for */
  Index *pIdx             /* Must be compatible with this index */
){
  int j;

  /* memset(pScan, 0, sizeof(*pScan)); */
  pScan->pOrigWC = pWC;
  pScan->pWC = pWC;
  if( pIdx && iColumn>=0 ){
    Index *pPk = sqlite4FindPrimaryKey(pIdx->pTable, 0);
    pScan->idxaff = pIdx->pTable->aCol[iColumn].affinity;
    for(j=0; idxColumnNumber(pIdx, pPk, j)!=iColumn; j++){
      if( NEVER(j>=idxColumnCount(pIdx, pPk)) ) return 0;
    }
    pScan->zCollName = idxColumnCollation(pIdx, pPk, j);
  }else{
    pScan->idxaff = 0;
    pScan->zCollName = 0;
  }
  pScan->opMask = opMask;
  pScan->k = 0;
  pScan->aEquiv[0] = iCur;
  pScan->aEquiv[1] = iColumn;
  pScan->nEquiv = 2;
  pScan->iEquiv = 2;
  return whereScanNext(pScan);
}

/*
** Search for a term in the WHERE clause that is of the form "X <op> <expr>"
** where X is a reference to the iColumn of table iCur and <op> is one of
** the WO_xx operator codes specified by the op parameter.
** Return a pointer to the term.  Return 0 if not found.
**
** The term returned might by Y=<expr> if there is another constraint in
** the WHERE clause that specifies that X=Y.  Any such constraints will be
** identified by the WO_EQUIV bit in the pTerm->eOperator field.  The
** aEquiv[] array holds X and all its equivalents, with each SQL variable
** taking up two slots in aEquiv[].  The first slot is for the cursor number
** and the second is for the column number.  There are 22 slots in aEquiv[]
** so that means we can look for X plus up to 10 other equivalent values.
** Hence a search for X will return <expr> if X=A1 and A1=A2 and A2=A3
** and ... and A9=A10 and A10=<expr>.
**
** If there are multiple terms in the WHERE clause of the form "X <op> <expr>"
** then try for the one with no dependencies on <expr> - in other words where
** <expr> is a constant expression of some kind.  Only return entries of
** the form "X <op> Y" where Y is a column in another table if no terms of
** the form "X <op> <const-expr>" exist.   If no terms with a constant RHS
** exist, try to return a term that does not use WO_EQUIV.
*/
static WhereTerm *findTerm(
  WhereClause *pWC,     /* The WHERE clause to be searched */
  int iCur,             /* Cursor number of LHS */
  int iColumn,          /* Column number of LHS */
  Bitmask notReady,     /* RHS must not overlap with this mask */
  u32 op,               /* Mask of WO_xx values describing operator */
  Index *pIdx           /* Must be compatible with this index, if not NULL */
){

  WhereTerm *pResult = 0;

  WhereTerm *p;
















  WhereScan scan;



  p = whereScanInit(&scan, pWC, iCur, iColumn, op, pIdx);


  while( p ){



    if( (p->prereqRight & notReady)==0 ){




      if( p->prereqRight==0 && (p->eOperator&WO_EQ)!=0 ){




        return p;
      }
      if( pResult==0 ) pResult = p;
    }
    p = whereScanNext(&scan);
  }
  return pResult;
}

/* Forward reference */
static void exprAnalyze(SrcList*, WhereClause*, int);

/*
** Call exprAnalyze on all terms in a WHERE clause.  





*/
static void exprAnalyzeAll(
  SrcList *pTabList,       /* the FROM clause */
  WhereClause *pWC         /* the WHERE clause to be analyzed */
){
  int i;
  for(i=pWC->nTerm-1; i>=0; i--){
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699

700


701
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    return 0;
  }
#ifdef SQLITE4_EBCDIC
  if( *pnoCase ) return 0;
#endif
  pList = pExpr->x.pList;
  pLeft = pList->a[1].pExpr;

  if( pLeft->op!=TK_COLUMN || sqlite4ExprAffinity(pLeft)!=SQLITE4_AFF_TEXT ){


    /* IMP: R-02065-49465 The left-hand side of the LIKE or GLOB operator must
    ** be the name of an indexed column with TEXT affinity. */
    return 0;
  }
  assert( pLeft->iColumn!=(-1) ); /* Because IPK never has AFF_TEXT */

  pRight = pList->a[0].pExpr;
  op = pRight->op;
  if( op==TK_REGISTER ){
    op = pRight->op2;
  }
  if( op==TK_VARIABLE ){
    Vdbe *pReprepare = pParse->pReprepare;
    int iCol = pRight->iColumn;
    pVal = sqlite4VdbeGetValue(pReprepare, iCol, SQLITE4_AFF_NONE);
    if( pVal && sqlite4_value_type(pVal)==SQLITE4_TEXT ){
      z = sqlite4_value_text(pVal, 0);
    }
    sqlite4VdbeSetVarmask(pParse->pVdbe, iCol);
    assert( pRight->op==TK_VARIABLE || pRight->op==TK_REGISTER );
  }else if( op==TK_STRING ){
    z = pRight->u.zToken;
  }
  if( z ){







>
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>
>
















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1117
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    return 0;
  }
#ifdef SQLITE4_EBCDIC
  if( *pnoCase ) return 0;
#endif
  pList = pExpr->x.pList;
  pLeft = pList->a[1].pExpr;
  if( pLeft->op!=TK_COLUMN 
   || sqlite4ExprAffinity(pLeft)!=SQLITE4_AFF_TEXT 
   || IsVirtual(pLeft->pTab)
  ){
    /* IMP: R-02065-49465 The left-hand side of the LIKE or GLOB operator must
    ** be the name of an indexed column with TEXT affinity. */
    return 0;
  }
  assert( pLeft->iColumn!=(-1) ); /* Because IPK never has AFF_TEXT */

  pRight = pList->a[0].pExpr;
  op = pRight->op;
  if( op==TK_REGISTER ){
    op = pRight->op2;
  }
  if( op==TK_VARIABLE ){
    Vdbe *pReprepare = pParse->pReprepare;
    int iCol = pRight->iColumn;
    pVal = sqlite4VdbeGetValue(pReprepare, iCol, SQLITE4_AFF_NONE);
    if( pVal && sqlite4_value_type(pVal)==SQLITE4_TEXT ){
      z = (char *)sqlite4_value_text(pVal, 0);
    }
    sqlite4VdbeSetVarmask(pParse->pVdbe, iCol);
    assert( pRight->op==TK_VARIABLE || pRight->op==TK_REGISTER );
  }else if( op==TK_STRING ){
    z = pRight->u.zToken;
  }
  if( z ){
821
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**     (B)     x=expr1 OR expr2=x OR x=expr3
**     (C)     t1.x=t2.y OR (t1.x=t2.z AND t1.y=15)
**     (D)     x=expr1 OR (y>11 AND y<22 AND z LIKE '*hello*')
**     (E)     (p.a=1 AND q.b=2 AND r.c=3) OR (p.x=4 AND q.y=5 AND r.z=6)
**
** CASE 1:
**
** If all subterms are of the form T.C=expr for some single column of C
** a single table T (as shown in example B above) then create a new virtual
** term that is an equivalent IN expression.  In other words, if the term
** being analyzed is:
**
**      x = expr1  OR  expr2 = x  OR  x = expr3
**
** then create a new virtual term like this:







|







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**     (B)     x=expr1 OR expr2=x OR x=expr3
**     (C)     t1.x=t2.y OR (t1.x=t2.z AND t1.y=15)
**     (D)     x=expr1 OR (y>11 AND y<22 AND z LIKE '*hello*')
**     (E)     (p.a=1 AND q.b=2 AND r.c=3) OR (p.x=4 AND q.y=5 AND r.z=6)
**
** CASE 1:
**
** If all subterms are of the form T.C=expr for some single column of C and
** a single table T (as shown in example B above) then create a new virtual
** term that is an equivalent IN expression.  In other words, if the term
** being analyzed is:
**
**      x = expr1  OR  expr2 = x  OR  x = expr3
**
** then create a new virtual term like this:
876
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** zero.  This term is not useful for search.
*/
static void exprAnalyzeOrTerm(
  SrcList *pSrc,            /* the FROM clause */
  WhereClause *pWC,         /* the complete WHERE clause */
  int idxTerm               /* Index of the OR-term to be analyzed */
){

  Parse *pParse = pWC->pParse;            /* Parser context */
  sqlite4 *db = pParse->db;               /* Database connection */
  WhereTerm *pTerm = &pWC->a[idxTerm];    /* The term to be analyzed */
  Expr *pExpr = pTerm->pExpr;             /* The expression of the term */
  WhereMaskSet *pMaskSet = pWC->pMaskSet; /* Table use masks */
  int i;                                  /* Loop counters */
  WhereClause *pOrWc;       /* Breakup of pTerm into subterms */
  WhereTerm *pOrTerm;       /* A Sub-term within the pOrWc */
  WhereOrInfo *pOrInfo;     /* Additional information associated with pTerm */
  Bitmask chngToIN;         /* Tables that might satisfy case 1 */
  Bitmask indexable;        /* Tables that are indexable, satisfying case 2 */

  /*
  ** Break the OR clause into its separate subterms.  The subterms are
  ** stored in a WhereClause structure containing within the WhereOrInfo
  ** object that is attached to the original OR clause term.
  */
  assert( (pTerm->wtFlags & (TERM_DYNAMIC|TERM_ORINFO|TERM_ANDINFO))==0 );
  assert( pExpr->op==TK_OR );
  pTerm->u.pOrInfo = pOrInfo = sqlite4DbMallocZero(db, sizeof(*pOrInfo));
  if( pOrInfo==0 ) return;
  pTerm->wtFlags |= TERM_ORINFO;
  pOrWc = &pOrInfo->wc;
  whereClauseInit(pOrWc, pWC->pParse, pMaskSet, pWC->wctrlFlags);
  whereSplit(pOrWc, pExpr, TK_OR);
  exprAnalyzeAll(pSrc, pOrWc);
  if( db->mallocFailed ) return;
  assert( pOrWc->nTerm>=2 );

  /*
  ** Compute the set of tables that might satisfy cases 1 or 2.
  */
  indexable = ~(Bitmask)0;
  chngToIN = ~(pWC->vmask);
  for(i=pOrWc->nTerm-1, pOrTerm=pOrWc->a; i>=0 && indexable; i--, pOrTerm++){
    if( (pOrTerm->eOperator & WO_SINGLE)==0 ){
      WhereAndInfo *pAndInfo;
      assert( pOrTerm->eOperator==0 );
      assert( (pOrTerm->wtFlags & (TERM_ANDINFO|TERM_ORINFO))==0 );
      chngToIN = 0;
      pAndInfo = sqlite4DbMallocRaw(db, sizeof(*pAndInfo));
      if( pAndInfo ){
        WhereClause *pAndWC;
        WhereTerm *pAndTerm;
        int j;
        Bitmask b = 0;
        pOrTerm->u.pAndInfo = pAndInfo;
        pOrTerm->wtFlags |= TERM_ANDINFO;
        pOrTerm->eOperator = WO_AND;
        pAndWC = &pAndInfo->wc;
        whereClauseInit(pAndWC, pWC->pParse, pMaskSet, pWC->wctrlFlags);
        whereSplit(pAndWC, pOrTerm->pExpr, TK_AND);
        exprAnalyzeAll(pSrc, pAndWC);
        pAndWC->pOuter = pWC;
        testcase( db->mallocFailed );
        if( !db->mallocFailed ){
          for(j=0, pAndTerm=pAndWC->a; j<pAndWC->nTerm; j++, pAndTerm++){
            assert( pAndTerm->pExpr );
            if( allowedOp(pAndTerm->pExpr->op) ){
              b |= getMask(pMaskSet, pAndTerm->leftCursor);
            }
          }
        }
        indexable &= b;
      }
    }else if( pOrTerm->wtFlags & TERM_COPIED ){
      /* Skip this term for now.  We revisit it when we process the
      ** corresponding TERM_VIRTUAL term */
    }else{
      Bitmask b;
      b = getMask(pMaskSet, pOrTerm->leftCursor);
      if( pOrTerm->wtFlags & TERM_VIRTUAL ){
        WhereTerm *pOther = &pOrWc->a[pOrTerm->iParent];
        b |= getMask(pMaskSet, pOther->leftCursor);
      }
      indexable &= b;
      if( pOrTerm->eOperator!=WO_EQ ){
        chngToIN = 0;
      }else{
        chngToIN &= b;
      }
    }
  }








>
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<


















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<












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|







1303
1304
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1307
1308
1309
1310
1311
1312
1313
1314

1315
1316
1317
1318
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1327
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1346

1347
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** zero.  This term is not useful for search.
*/
static void exprAnalyzeOrTerm(
  SrcList *pSrc,            /* the FROM clause */
  WhereClause *pWC,         /* the complete WHERE clause */
  int idxTerm               /* Index of the OR-term to be analyzed */
){
  WhereInfo *pWInfo = pWC->pWInfo;        /* WHERE clause processing context */
  Parse *pParse = pWInfo->pParse;         /* Parser context */
  sqlite4 *db = pParse->db;               /* Database connection */
  WhereTerm *pTerm = &pWC->a[idxTerm];    /* The term to be analyzed */
  Expr *pExpr = pTerm->pExpr;             /* The expression of the term */

  int i;                                  /* Loop counters */
  WhereClause *pOrWc;       /* Breakup of pTerm into subterms */
  WhereTerm *pOrTerm;       /* A Sub-term within the pOrWc */
  WhereOrInfo *pOrInfo;     /* Additional information associated with pTerm */
  Bitmask chngToIN;         /* Tables that might satisfy case 1 */
  Bitmask indexable;        /* Tables that are indexable, satisfying case 2 */

  /*
  ** Break the OR clause into its separate subterms.  The subterms are
  ** stored in a WhereClause structure containing within the WhereOrInfo
  ** object that is attached to the original OR clause term.
  */
  assert( (pTerm->wtFlags & (TERM_DYNAMIC|TERM_ORINFO|TERM_ANDINFO))==0 );
  assert( pExpr->op==TK_OR );
  pTerm->u.pOrInfo = pOrInfo = sqlite4DbMallocZero(db, sizeof(*pOrInfo));
  if( pOrInfo==0 ) return;
  pTerm->wtFlags |= TERM_ORINFO;
  pOrWc = &pOrInfo->wc;
  whereClauseInit(pOrWc, pWInfo);
  whereSplit(pOrWc, pExpr, TK_OR);
  exprAnalyzeAll(pSrc, pOrWc);
  if( db->mallocFailed ) return;
  assert( pOrWc->nTerm>=2 );

  /*
  ** Compute the set of tables that might satisfy cases 1 or 2.
  */
  indexable = ~(Bitmask)0;
  chngToIN = ~(Bitmask)0;
  for(i=pOrWc->nTerm-1, pOrTerm=pOrWc->a; i>=0 && indexable; i--, pOrTerm++){
    if( (pOrTerm->eOperator & WO_SINGLE)==0 ){
      WhereAndInfo *pAndInfo;

      assert( (pOrTerm->wtFlags & (TERM_ANDINFO|TERM_ORINFO))==0 );
      chngToIN = 0;
      pAndInfo = sqlite4DbMallocRaw(db, sizeof(*pAndInfo));
      if( pAndInfo ){
        WhereClause *pAndWC;
        WhereTerm *pAndTerm;
        int j;
        Bitmask b = 0;
        pOrTerm->u.pAndInfo = pAndInfo;
        pOrTerm->wtFlags |= TERM_ANDINFO;
        pOrTerm->eOperator = WO_AND;
        pAndWC = &pAndInfo->wc;
        whereClauseInit(pAndWC, pWC->pWInfo);
        whereSplit(pAndWC, pOrTerm->pExpr, TK_AND);
        exprAnalyzeAll(pSrc, pAndWC);
        pAndWC->pOuter = pWC;
        testcase( db->mallocFailed );
        if( !db->mallocFailed ){
          for(j=0, pAndTerm=pAndWC->a; j<pAndWC->nTerm; j++, pAndTerm++){
            assert( pAndTerm->pExpr );
            if( allowedOp(pAndTerm->pExpr->op) ){
              b |= getMask(&pWInfo->sMaskSet, pAndTerm->leftCursor);
            }
          }
        }
        indexable &= b;
      }
    }else if( pOrTerm->wtFlags & TERM_COPIED ){
      /* Skip this term for now.  We revisit it when we process the
      ** corresponding TERM_VIRTUAL term */
    }else{
      Bitmask b;
      b = getMask(&pWInfo->sMaskSet, pOrTerm->leftCursor);
      if( pOrTerm->wtFlags & TERM_VIRTUAL ){
        WhereTerm *pOther = &pOrWc->a[pOrTerm->iParent];
        b |= getMask(&pWInfo->sMaskSet, pOther->leftCursor);
      }
      indexable &= b;
      if( (pOrTerm->eOperator & WO_EQ)==0 ){
        chngToIN = 0;
      }else{
        chngToIN &= b;
      }
    }
  }

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1053
    ** will be recorded in iCursor and iColumn.  There might not be any
    ** such table and column.  Set okToChngToIN if an appropriate table
    ** and column is found but leave okToChngToIN false if not found.
    */
    for(j=0; j<2 && !okToChngToIN; j++){
      pOrTerm = pOrWc->a;
      for(i=pOrWc->nTerm-1; i>=0; i--, pOrTerm++){
        assert( pOrTerm->eOperator==WO_EQ );
        pOrTerm->wtFlags &= ~TERM_OR_OK;
        if( pOrTerm->leftCursor==iCursor ){
          /* This is the 2-bit case and we are on the second iteration and
          ** current term is from the first iteration.  So skip this term. */
          assert( j==1 );
          continue;
        }
        if( (chngToIN & getMask(pMaskSet, pOrTerm->leftCursor))==0 ){
          /* This term must be of the form t1.a==t2.b where t2 is in the
          ** chngToIN set but t1 is not.  This term will be either preceeded
          ** or follwed by an inverted copy (t2.b==t1.a).  Skip this term 
          ** and use its inversion. */
          testcase( pOrTerm->wtFlags & TERM_COPIED );
          testcase( pOrTerm->wtFlags & TERM_VIRTUAL );
          assert( pOrTerm->wtFlags & (TERM_COPIED|TERM_VIRTUAL) );
          continue;
        }
        iColumn = pOrTerm->u.leftColumn;
        iCursor = pOrTerm->leftCursor;
        break;
      }
      if( i<0 ){
        /* No candidate table+column was found.  This can only occur
        ** on the second iteration */
        assert( j==1 );
        assert( (chngToIN&(chngToIN-1))==0 );
        assert( chngToIN==getMask(pMaskSet, iCursor) );
        break;
      }
      testcase( j==1 );

      /* We have found a candidate table and column.  Check to see if that
      ** table and column is common to every term in the OR clause */
      okToChngToIN = 1;
      for(; i>=0 && okToChngToIN; i--, pOrTerm++){
        assert( pOrTerm->eOperator==WO_EQ );
        if( pOrTerm->leftCursor!=iCursor ){
          pOrTerm->wtFlags &= ~TERM_OR_OK;
        }else if( pOrTerm->u.leftColumn!=iColumn ){
          okToChngToIN = 0;
        }else{
          int affLeft, affRight;
          /* If the right-hand side is also a column, then the affinities







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    ** will be recorded in iCursor and iColumn.  There might not be any
    ** such table and column.  Set okToChngToIN if an appropriate table
    ** and column is found but leave okToChngToIN false if not found.
    */
    for(j=0; j<2 && !okToChngToIN; j++){
      pOrTerm = pOrWc->a;
      for(i=pOrWc->nTerm-1; i>=0; i--, pOrTerm++){
        assert( pOrTerm->eOperator & WO_EQ );
        pOrTerm->wtFlags &= ~TERM_OR_OK;
        if( pOrTerm->leftCursor==iCursor ){
          /* This is the 2-bit case and we are on the second iteration and
          ** current term is from the first iteration.  So skip this term. */
          assert( j==1 );
          continue;
        }
        if( (chngToIN & getMask(&pWInfo->sMaskSet, pOrTerm->leftCursor))==0 ){
          /* This term must be of the form t1.a==t2.b where t2 is in the
          ** chngToIN set but t1 is not.  This term will be either preceeded
          ** or follwed by an inverted copy (t2.b==t1.a).  Skip this term 
          ** and use its inversion. */
          testcase( pOrTerm->wtFlags & TERM_COPIED );
          testcase( pOrTerm->wtFlags & TERM_VIRTUAL );
          assert( pOrTerm->wtFlags & (TERM_COPIED|TERM_VIRTUAL) );
          continue;
        }
        iColumn = pOrTerm->u.leftColumn;
        iCursor = pOrTerm->leftCursor;
        break;
      }
      if( i<0 ){
        /* No candidate table+column was found.  This can only occur
        ** on the second iteration */
        assert( j==1 );
        assert( IsPowerOfTwo(chngToIN) );
        assert( chngToIN==getMask(&pWInfo->sMaskSet, iCursor) );
        break;
      }
      testcase( j==1 );

      /* We have found a candidate table and column.  Check to see if that
      ** table and column is common to every term in the OR clause */
      okToChngToIN = 1;
      for(; i>=0 && okToChngToIN; i--, pOrTerm++){
        assert( pOrTerm->eOperator & WO_EQ );
        if( pOrTerm->leftCursor!=iCursor ){
          pOrTerm->wtFlags &= ~TERM_OR_OK;
        }else if( pOrTerm->u.leftColumn!=iColumn ){
          okToChngToIN = 0;
        }else{
          int affLeft, affRight;
          /* If the right-hand side is also a column, then the affinities
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      Expr *pDup;            /* A transient duplicate expression */
      ExprList *pList = 0;   /* The RHS of the IN operator */
      Expr *pLeft = 0;       /* The LHS of the IN operator */
      Expr *pNew;            /* The complete IN operator */

      for(i=pOrWc->nTerm-1, pOrTerm=pOrWc->a; i>=0; i--, pOrTerm++){
        if( (pOrTerm->wtFlags & TERM_OR_OK)==0 ) continue;
        assert( pOrTerm->eOperator==WO_EQ );
        assert( pOrTerm->leftCursor==iCursor );
        assert( pOrTerm->u.leftColumn==iColumn );
        pDup = sqlite4ExprDup(db, pOrTerm->pExpr->pRight, 0);
        pList = sqlite4ExprListAppend(pWC->pParse, pList, pDup);
        pLeft = pOrTerm->pExpr->pLeft;
      }
      assert( pLeft!=0 );
      pDup = sqlite4ExprDup(db, pLeft, 0);
      pNew = sqlite4PExpr(pParse, TK_IN, pDup, 0, 0);
      if( pNew ){
        int idxNew;







|



|







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      Expr *pDup;            /* A transient duplicate expression */
      ExprList *pList = 0;   /* The RHS of the IN operator */
      Expr *pLeft = 0;       /* The LHS of the IN operator */
      Expr *pNew;            /* The complete IN operator */

      for(i=pOrWc->nTerm-1, pOrTerm=pOrWc->a; i>=0; i--, pOrTerm++){
        if( (pOrTerm->wtFlags & TERM_OR_OK)==0 ) continue;
        assert( pOrTerm->eOperator & WO_EQ );
        assert( pOrTerm->leftCursor==iCursor );
        assert( pOrTerm->u.leftColumn==iColumn );
        pDup = sqlite4ExprDup(db, pOrTerm->pExpr->pRight, 0);
        pList = sqlite4ExprListAppend(pWInfo->pParse, pList, pDup);
        pLeft = pOrTerm->pExpr->pLeft;
      }
      assert( pLeft!=0 );
      pDup = sqlite4ExprDup(db, pLeft, 0);
      pNew = sqlite4PExpr(pParse, TK_IN, pDup, 0, 0);
      if( pNew ){
        int idxNew;
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      }
      pTerm->eOperator = WO_NOOP;  /* case 1 trumps case 2 */
    }
  }
}
#endif /* !SQLITE4_OMIT_OR_OPTIMIZATION && !SQLITE4_OMIT_SUBQUERY */


/*
** The input to this routine is an WhereTerm structure with only the
** "pExpr" field filled in.  The job of this routine is to analyze the
** subexpression and populate all the other fields of the WhereTerm
** structure.
**
** If the expression is of the form "<expr> <op> X" it gets commuted







<







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      }
      pTerm->eOperator = WO_NOOP;  /* case 1 trumps case 2 */
    }
  }
}
#endif /* !SQLITE4_OMIT_OR_OPTIMIZATION && !SQLITE4_OMIT_SUBQUERY */


/*
** The input to this routine is an WhereTerm structure with only the
** "pExpr" field filled in.  The job of this routine is to analyze the
** subexpression and populate all the other fields of the WhereTerm
** structure.
**
** If the expression is of the form "<expr> <op> X" it gets commuted
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** and the copy has idxParent set to the index of the original term.
*/
static void exprAnalyze(
  SrcList *pSrc,            /* the FROM clause */
  WhereClause *pWC,         /* the WHERE clause */
  int idxTerm               /* Index of the term to be analyzed */
){

  WhereTerm *pTerm;                /* The term to be analyzed */
  WhereMaskSet *pMaskSet;          /* Set of table index masks */
  Expr *pExpr;                     /* The expression to be analyzed */
  Bitmask prereqLeft;              /* Prerequesites of the pExpr->pLeft */
  Bitmask prereqAll;               /* Prerequesites of pExpr */
  Bitmask extraRight = 0;          /* Extra dependencies on LEFT JOIN */
  Expr *pStr1 = 0;                 /* RHS of LIKE/GLOB operator */
  int isComplete = 0;              /* RHS of LIKE/GLOB ends with wildcard */
  int noCase = 0;                  /* LIKE/GLOB distinguishes case */
  int op;                          /* Top-level operator.  pExpr->op */
  Parse *pParse = pWC->pParse;     /* Parsing context */
  sqlite4 *db = pParse->db;        /* Database connection */

  if( db->mallocFailed ){
    return;
  }
  pTerm = &pWC->a[idxTerm];
  pMaskSet = pWC->pMaskSet;
  pExpr = pTerm->pExpr;

  prereqLeft = exprTableUsage(pMaskSet, pExpr->pLeft);
  op = pExpr->op;
  if( op==TK_IN ){
    assert( pExpr->pRight==0 );
    if( ExprHasProperty(pExpr, EP_xIsSelect) ){
      pTerm->prereqRight = exprSelectTableUsage(pMaskSet, pExpr->x.pSelect);
    }else{







>










|






|

>







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** and the copy has idxParent set to the index of the original term.
*/
static void exprAnalyze(
  SrcList *pSrc,            /* the FROM clause */
  WhereClause *pWC,         /* the WHERE clause */
  int idxTerm               /* Index of the term to be analyzed */
){
  WhereInfo *pWInfo = pWC->pWInfo; /* WHERE clause processing context */
  WhereTerm *pTerm;                /* The term to be analyzed */
  WhereMaskSet *pMaskSet;          /* Set of table index masks */
  Expr *pExpr;                     /* The expression to be analyzed */
  Bitmask prereqLeft;              /* Prerequesites of the pExpr->pLeft */
  Bitmask prereqAll;               /* Prerequesites of pExpr */
  Bitmask extraRight = 0;          /* Extra dependencies on LEFT JOIN */
  Expr *pStr1 = 0;                 /* RHS of LIKE/GLOB operator */
  int isComplete = 0;              /* RHS of LIKE/GLOB ends with wildcard */
  int noCase = 0;                  /* LIKE/GLOB distinguishes case */
  int op;                          /* Top-level operator.  pExpr->op */
  Parse *pParse = pWInfo->pParse;  /* Parsing context */
  sqlite4 *db = pParse->db;        /* Database connection */

  if( db->mallocFailed ){
    return;
  }
  pTerm = &pWC->a[idxTerm];
  pMaskSet = &pWInfo->sMaskSet;
  pExpr = pTerm->pExpr;
  assert( pExpr->op!=TK_AS && pExpr->op!=TK_COLLATE );
  prereqLeft = exprTableUsage(pMaskSet, pExpr->pLeft);
  op = pExpr->op;
  if( op==TK_IN ){
    assert( pExpr->pRight==0 );
    if( ExprHasProperty(pExpr, EP_xIsSelect) ){
      pTerm->prereqRight = exprSelectTableUsage(pMaskSet, pExpr->x.pSelect);
    }else{
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    extraRight = x-1;  /* ON clause terms may not be used with an index
                       ** on left table of a LEFT JOIN.  Ticket #3015 */
  }
  pTerm->prereqAll = prereqAll;
  pTerm->leftCursor = -1;
  pTerm->iParent = -1;
  pTerm->eOperator = 0;
  if( allowedOp(op) && (pTerm->prereqRight & prereqLeft)==0 ){
    Expr *pLeft = pExpr->pLeft;
    Expr *pRight = pExpr->pRight;

    if( pLeft->op==TK_COLUMN ){
      pTerm->leftCursor = pLeft->iTable;
      pTerm->u.leftColumn = pLeft->iColumn;
      pTerm->eOperator = operatorMask(op);
    }
    if( pRight && pRight->op==TK_COLUMN ){
      WhereTerm *pNew;
      Expr *pDup;

      if( pTerm->leftCursor>=0 ){
        int idxNew;
        pDup = sqlite4ExprDup(db, pExpr, 0);
        if( db->mallocFailed ){
          sqlite4ExprDelete(db, pDup);
          return;
        }
        idxNew = whereClauseInsert(pWC, pDup, TERM_VIRTUAL|TERM_DYNAMIC);
        if( idxNew==0 ) return;
        pNew = &pWC->a[idxNew];
        pNew->iParent = idxTerm;
        pTerm = &pWC->a[idxTerm];
        pTerm->nChild = 1;
        pTerm->wtFlags |= TERM_COPIED;







      }else{
        pDup = pExpr;
        pNew = pTerm;
      }
      exprCommute(pParse, pDup);
      pLeft = pDup->pLeft;
      pNew->leftCursor = pLeft->iTable;
      pNew->u.leftColumn = pLeft->iColumn;
      testcase( (prereqLeft | extraRight) != prereqLeft );
      pNew->prereqRight = prereqLeft | extraRight;
      pNew->prereqAll = prereqAll;
      pNew->eOperator = operatorMask(pDup->op);
    }
  }

#ifndef SQLITE4_OMIT_BETWEEN_OPTIMIZATION
  /* If a term is the BETWEEN operator, create two new virtual terms
  ** that define the range that the BETWEEN implements.  For example:
  **







|
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>



|




>














>
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>
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>





|





|







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    extraRight = x-1;  /* ON clause terms may not be used with an index
                       ** on left table of a LEFT JOIN.  Ticket #3015 */
  }
  pTerm->prereqAll = prereqAll;
  pTerm->leftCursor = -1;
  pTerm->iParent = -1;
  pTerm->eOperator = 0;
  if( allowedOp(op) ){
    Expr *pLeft = sqlite4ExprSkipCollate(pExpr->pLeft);
    Expr *pRight = sqlite4ExprSkipCollate(pExpr->pRight);
    u16 opMask = (pTerm->prereqRight & prereqLeft)==0 ? WO_ALL : WO_EQUIV;
    if( pLeft->op==TK_COLUMN ){
      pTerm->leftCursor = pLeft->iTable;
      pTerm->u.leftColumn = pLeft->iColumn;
      pTerm->eOperator = operatorMask(op) & opMask;
    }
    if( pRight && pRight->op==TK_COLUMN ){
      WhereTerm *pNew;
      Expr *pDup;
      u16 eExtraOp = 0;        /* Extra bits for pNew->eOperator */
      if( pTerm->leftCursor>=0 ){
        int idxNew;
        pDup = sqlite4ExprDup(db, pExpr, 0);
        if( db->mallocFailed ){
          sqlite4ExprDelete(db, pDup);
          return;
        }
        idxNew = whereClauseInsert(pWC, pDup, TERM_VIRTUAL|TERM_DYNAMIC);
        if( idxNew==0 ) return;
        pNew = &pWC->a[idxNew];
        pNew->iParent = idxTerm;
        pTerm = &pWC->a[idxTerm];
        pTerm->nChild = 1;
        pTerm->wtFlags |= TERM_COPIED;
        if( pExpr->op==TK_EQ
         && !ExprHasProperty(pExpr, EP_FromJoin)
         && OptimizationEnabled(db, SQLITE4_Transitive)
        ){
          pTerm->eOperator |= WO_EQUIV;
          eExtraOp = WO_EQUIV;
        }
      }else{
        pDup = pExpr;
        pNew = pTerm;
      }
      exprCommute(pParse, pDup);
      pLeft = sqlite4ExprSkipCollate(pDup->pLeft);
      pNew->leftCursor = pLeft->iTable;
      pNew->u.leftColumn = pLeft->iColumn;
      testcase( (prereqLeft | extraRight) != prereqLeft );
      pNew->prereqRight = prereqLeft | extraRight;
      pNew->prereqAll = prereqAll;
      pNew->eOperator = (operatorMask(pDup->op) + eExtraOp) & opMask;
    }
  }

#ifndef SQLITE4_OMIT_BETWEEN_OPTIMIZATION
  /* If a term is the BETWEEN operator, create two new virtual terms
  ** that define the range that the BETWEEN implements.  For example:
  **
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  ){
    Expr *pLeft;       /* LHS of LIKE/GLOB operator */
    Expr *pStr2;       /* Copy of pStr1 - RHS of LIKE/GLOB operator */
    Expr *pNewExpr1;
    Expr *pNewExpr2;
    int idxNew1;
    int idxNew2;
    CollSeq *pColl;    /* Collating sequence to use */

    pLeft = pExpr->x.pList->a[1].pExpr;
    pStr2 = sqlite4ExprDup(db, pStr1, 0);
    if( !db->mallocFailed ){
      u8 c, *pC;       /* Last character before the first wildcard */
      pC = (u8*)&pStr2->u.zToken[sqlite4Strlen30(pStr2->u.zToken)-1];
      c = *pC;







|







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  ){
    Expr *pLeft;       /* LHS of LIKE/GLOB operator */
    Expr *pStr2;       /* Copy of pStr1 - RHS of LIKE/GLOB operator */
    Expr *pNewExpr1;
    Expr *pNewExpr2;
    int idxNew1;
    int idxNew2;
    Token sCollSeqName;  /* Name of collating sequence */

    pLeft = pExpr->x.pList->a[1].pExpr;
    pStr2 = sqlite4ExprDup(db, pStr1, 0);
    if( !db->mallocFailed ){
      u8 c, *pC;       /* Last character before the first wildcard */
      pC = (u8*)&pStr2->u.zToken[sqlite4Strlen30(pStr2->u.zToken)-1];
      c = *pC;
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        if( c=='A'-1 ) isComplete = 0;   /* EV: R-64339-08207 */


        c = sqlite4UpperToLower[c];
      }
      *pC = c + 1;
    }
    pColl = sqlite4FindCollSeq(db, noCase ? "NOCASE" : "BINARY",0);

    pNewExpr1 = sqlite4PExpr(pParse, TK_GE, 
                     sqlite4ExprSetColl(sqlite4ExprDup(db,pLeft,0), pColl),
                     pStr1, 0);
    idxNew1 = whereClauseInsert(pWC, pNewExpr1, TERM_VIRTUAL|TERM_DYNAMIC);
    testcase( idxNew1==0 );
    exprAnalyze(pSrc, pWC, idxNew1);
    pNewExpr2 = sqlite4PExpr(pParse, TK_LT,
                     sqlite4ExprSetColl(sqlite4ExprDup(db,pLeft,0), pColl),
                     pStr2, 0);
    idxNew2 = whereClauseInsert(pWC, pNewExpr2, TERM_VIRTUAL|TERM_DYNAMIC);
    testcase( idxNew2==0 );
    exprAnalyze(pSrc, pWC, idxNew2);
    pTerm = &pWC->a[idxTerm];
    if( isComplete ){
      pWC->a[idxNew1].iParent = idxTerm;
      pWC->a[idxNew2].iParent = idxTerm;







|
>
|
|
|



|
|
|







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        if( c=='A'-1 ) isComplete = 0;   /* EV: R-64339-08207 */


        c = sqlite4UpperToLower[c];
      }
      *pC = c + 1;
    }
    sCollSeqName.z = noCase ? "NOCASE" : "BINARY";
    sCollSeqName.n = 6;
    pNewExpr1 = sqlite4ExprDup(db, pLeft, 0);
    sqlite4ExprSetCollByToken(pParse, pNewExpr1, &sCollSeqName);
    pNewExpr1 = sqlite4PExpr(pParse, TK_GE, pNewExpr1, pStr1, 0);
    idxNew1 = whereClauseInsert(pWC, pNewExpr1, TERM_VIRTUAL|TERM_DYNAMIC);
    testcase( idxNew1==0 );
    exprAnalyze(pSrc, pWC, idxNew1);
    pNewExpr2 = sqlite4ExprDup(db, pLeft, 0);
    sqlite4ExprSetCollByToken(pParse, pNewExpr2, &sCollSeqName);
    pNewExpr2 = sqlite4PExpr(pParse, TK_LT, pNewExpr2, pStr2, 0);
    idxNew2 = whereClauseInsert(pWC, pNewExpr2, TERM_VIRTUAL|TERM_DYNAMIC);
    testcase( idxNew2==0 );
    exprAnalyze(pSrc, pWC, idxNew2);
    pTerm = &pWC->a[idxTerm];
    if( isComplete ){
      pWC->a[idxNew1].iParent = idxTerm;
      pWC->a[idxNew2].iParent = idxTerm;
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  ** TERM_VNULL tag will suppress the not-null check at the beginning
  ** of the loop.  Without the TERM_VNULL flag, the not-null check at
  ** the start of the loop will prevent any results from being returned.
  */
  if( pExpr->op==TK_NOTNULL
   && pExpr->pLeft->op==TK_COLUMN
   && pExpr->pLeft->iColumn>=0

  ){
    Expr *pNewExpr;
    Expr *pLeft = pExpr->pLeft;
    int idxNew;
    WhereTerm *pNewTerm;

    pNewExpr = sqlite4PExpr(pParse, TK_GT,







>







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  ** TERM_VNULL tag will suppress the not-null check at the beginning
  ** of the loop.  Without the TERM_VNULL flag, the not-null check at
  ** the start of the loop will prevent any results from being returned.
  */
  if( pExpr->op==TK_NOTNULL
   && pExpr->pLeft->op==TK_COLUMN
   && pExpr->pLeft->iColumn>=0
   && OptimizationEnabled(db, SQLITE4_Stat3)
  ){
    Expr *pNewExpr;
    Expr *pLeft = pExpr->pLeft;
    int idxNew;
    WhereTerm *pNewTerm;

    pNewExpr = sqlite4PExpr(pParse, TK_GT,
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  /* Prevent ON clause terms of a LEFT JOIN from being used to drive
  ** an index for tables to the left of the join.
  */
  pTerm->prereqRight |= extraRight;
}

/*
** Return TRUE if any of the expressions in pList->a[iFirst...] contain
** a reference to any table other than the iBase table.
*/
static int referencesOtherTables(
  ExprList *pList,          /* Search expressions in ths list */
  WhereMaskSet *pMaskSet,   /* Mapping from tables to bitmaps */
  int iFirst,               /* Be searching with the iFirst-th expression */
  int iBase                 /* Ignore references to this table */
){
  Bitmask allowed = ~getMask(pMaskSet, iBase);
  while( iFirst<pList->nExpr ){
    if( (exprTableUsage(pMaskSet, pList->a[iFirst++].pExpr)&allowed)!=0 ){
      return 1;
    }
  }
  return 0;
}

/*
** This function searches the expression list passed as the second argument
** for an expression of type TK_COLUMN that refers to the same column and
** uses the same collation sequence as the iCol'th column of index pIdx.
** Argument iBase is the cursor number used for the table that pIdx refers
** to.
**
** If such an expression is found, its index in pList->a[] is returned. If
** no expression is found, -1 is returned.
*/
static int findIndexCol(
  Parse *pParse,                  /* Parse context */
  ExprList *pList,                /* Expression list to search */
  int iBase,                      /* Cursor for table associated with pIdx */
  Index *pIdx,                    /* Index to match column of */
  int iCol                        /* Column of index to match */
){
  int i;
  const char *zColl = pIdx->azColl[iCol];

  for(i=0; i<pList->nExpr; i++){
    Expr *p = pList->a[i].pExpr;
    if( p->op==TK_COLUMN
     && p->iColumn==pIdx->aiColumn[iCol]
     && p->iTable==iBase
    ){
      CollSeq *pColl = sqlite4ExprCollSeq(pParse, p);
      assert( pColl || p->iColumn==-1 );
      if( 0==pColl || 0==sqlite4_stricmp(pColl->zName, zColl) ){
        return i;
      }
    }
  }

  return -1;
}

/*
** This routine determines if pIdx can be used to assist in processing a
** DISTINCT qualifier. In other words, it tests whether or not using this
** index for the outer loop guarantees that rows with equal values for
** all expressions in the pDistinct list are delivered grouped together.
**
** For example, the query 
**
**   SELECT DISTINCT a, b, c FROM tbl WHERE a = ?
**
** can benefit from any index on columns "b" and "c".
*/
static int isDistinctIndex(
  Parse *pParse,                  /* Parsing context */
  WhereClause *pWC,               /* The WHERE clause */
  Index *pIdx,                    /* The index being considered */
  int base,                       /* Cursor number for the table pIdx is on */
  ExprList *pDistinct,            /* The DISTINCT expressions */
  int nEqCol                      /* Number of index columns with == */
){
  Bitmask mask = 0;               /* Mask of unaccounted for pDistinct exprs */
  int i;                          /* Iterator variable */

  if( pIdx->zName==0 || pDistinct==0 || pDistinct->nExpr>=BMS ) return 0;
  testcase( pDistinct->nExpr==BMS-1 );

  /* Loop through all the expressions in the distinct list. If any of them
  ** are not simple column references, return early. Otherwise, test if the
  ** WHERE clause contains a "col=X" clause. If it does, the expression
  ** can be ignored. If it does not, and the column does not belong to the
  ** same table as index pIdx, return early. Finally, if there is no
  ** matching "col=X" expression and the column is on the same table as pIdx,
  ** set the corresponding bit in variable mask.
  */
  for(i=0; i<pDistinct->nExpr; i++){
    WhereTerm *pTerm;
    Expr *p = pDistinct->a[i].pExpr;
    if( p->op!=TK_COLUMN ) return 0;
    pTerm = findTerm(pWC, p->iTable, p->iColumn, ~(Bitmask)0, WO_EQ, 0);
    if( pTerm ){
      Expr *pX = pTerm->pExpr;
      CollSeq *p1 = sqlite4BinaryCompareCollSeq(pParse, pX->pLeft, pX->pRight);
      CollSeq *p2 = sqlite4ExprCollSeq(pParse, p);
      if( p1==p2 ) continue;
    }
    if( p->iTable!=base ) return 0;
    mask |= (((Bitmask)1) << i);
  }

  for(i=nEqCol; mask && i<pIdx->nColumn; i++){
    int iExpr = findIndexCol(pParse, pDistinct, base, pIdx, i);
    if( iExpr<0 ) break;
    mask &= ~(((Bitmask)1) << iExpr);
  }

  return (mask==0);
}


/*
** Return true if the DISTINCT expression-list passed as the third argument
** is redundant. A DISTINCT list is redundant if the database contains a
** UNIQUE index that guarantees that the result of the query will be distinct
** anyway.
*/
static int isDistinctRedundant(
  Parse *pParse,
  SrcList *pTabList,
  WhereClause *pWC,
  ExprList *pDistinct
){
  Table *pTab;
  Index *pIdx;
  int i;                          
  int iBase;

  /* If there is more than one table or sub-select in the FROM clause of
  ** this query, then it will not be possible to show that the DISTINCT 
  ** clause is redundant. */
  if( pTabList->nSrc!=1 ) return 0;
  iBase = pTabList->a[0].iCursor;
  pTab = pTabList->a[0].pTab;

  /* If any of the expressions is an IPK column on table iBase, then return 
  ** true. Note: The (p->iTable==iBase) part of this test may be false if the
  ** current SELECT is a correlated sub-query.
  */
  for(i=0; i<pDistinct->nExpr; i++){
    Expr *p = pDistinct->a[i].pExpr;
    if( p->op==TK_COLUMN && p->iTable==iBase && p->iColumn<0 ) return 1;
  }

  /* Loop through all indices on the table, checking each to see if it makes
  ** the DISTINCT qualifier redundant. It does so if:
  **
  **   1. The index is itself UNIQUE, and
  **
  **   2. All of the columns in the index are either part of the pDistinct
  **      list, or else the WHERE clause contains a term of the form "col=X",
  **      where X is a constant value. The collation sequences of the
  **      comparison and select-list expressions must match those of the index.



  */
  for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
    if( pIdx->onError==OE_None ) continue;
    for(i=0; i<pIdx->nColumn; i++){
      int iCol = pIdx->aiColumn[i];
      if( 0==findTerm(pWC, iBase, iCol, ~(Bitmask)0, WO_EQ, pIdx) 
       && 0>findIndexCol(pParse, pDistinct, iBase, pIdx, i)
      ){
        break;

      }
    }
    if( i==pIdx->nColumn ){
      /* This index implies that the DISTINCT qualifier is redundant. */
      return 1;
    }
  }

  return 0;
}


/*
** Return the table column number of the iIdxCol'th field in the index
** keys used by index pIdx, including any appended PRIMARY KEY fields.
** If there is no iIdxCol'th field in index pIdx, return -2.
**
** Example:
**
**   CREATE TABLE t1(a, b, c, PRIMARY KEY(a, b));
**   CREATE INDEX i1 ON t1(c);
**
** Index i1 in the example above consists of three fields - the indexed
** field "c" followed by the two primary key fields. The automatic PRIMARY
** KEY index consists of two fields only.
*/
static int idxColumnNumber(Index *pIdx, Index *pPk, int iIdxCol){
  int iRet = -2;
  if( iIdxCol<pIdx->nColumn ){
    iRet = pIdx->aiColumn[iIdxCol];
  }else if( pPk && iIdxCol<(pIdx->nColumn + pPk->nColumn) ){
    iRet = pPk->aiColumn[iIdxCol - pIdx->nColumn];
  }
  return iRet;
}

/*
** Return the name of the iCol'th column of table pTab. Or, if iCol is less
** than zero, return a pointer to the constant string "rowid".
*/
static const char *tblColumnName(Table *pTab, int iCol){
  if( iCol<0 ) return "rowid";
  return pTab->aCol[iCol].zName;
}

/*
** This routine decides if pIdx can be used to satisfy the ORDER BY
** clause.  If it can, it returns 1.  If pIdx cannot satisfy the
** ORDER BY clause, this routine returns 0.
**
** pOrderBy is an ORDER BY clause from a SELECT statement.  pTab is the
** left-most table in the FROM clause of that same SELECT statement and
** the table has a cursor number of "base".  pIdx is an index on pTab.
**
** nEqCol is the number of columns of pIdx that are used as equality
** constraints.  Any of these columns may be missing from the ORDER BY
** clause and the match can still be a success.
**
** All terms of the ORDER BY that match against the index must be either
** ASC or DESC.  (Terms of the ORDER BY clause past the end of a UNIQUE
** index do not need to satisfy this constraint.)  The *pbRev value is
** set to 1 if the ORDER BY clause is all DESC and it is set to 0 if
** the ORDER BY clause is all ASC.
*/
static int isSortingIndex(
  Parse *pParse,          /* Parsing context */
  WhereMaskSet *pMaskSet, /* Mapping from table cursor numbers to bitmaps */
  Index *pIdx,            /* The index we are testing */
  int base,               /* Cursor number for the table to be sorted */
  ExprList *pOrderBy,     /* The ORDER BY clause */
  int nEqCol,             /* Number of index columns with == constraints */
  int wsFlags,            /* Index usages flags */
  int *pbRev              /* Set to 1 if ORDER BY is DESC */
){
  sqlite4 *db = pParse->db;       /* Database handle */
  int sortOrder = 0;              /* XOR of index and ORDER BY sort direction */
  int nTerm;                      /* Number of ORDER BY terms */
  int iTerm;                      /* Used to iterate through nTerm terms */
  int iNext = nEqCol;             /* Index of next unmatched column in index */
  int nIdxCol;                    /* Number of columns in index, incl. PK */
  Index *pPk;
  Table *pTab;


  if( !pOrderBy ) return 0;
  if( wsFlags & WHERE_COLUMN_IN ) return 0;
  if( pIdx->fIndex & IDX_Unordered ) return 0;

  pTab = pIdx->pTable;
  pPk = sqlite4FindPrimaryKey(pTab, 0);
  nTerm = pOrderBy->nExpr;
  nIdxCol = pIdx->nColumn + (pIdx==pPk ? 0 : pPk->nColumn);

  assert( nTerm>0 );
  assert( pIdx && pIdx->zName );

  for(iTerm=0; iTerm<nTerm; iTerm++){
    ExprListItem *pTerm;  /* iTerm'th term of ORDER BY clause */
    int iIdxCol;                  /* Index of column in index records */

    Expr *pExpr;       /* The expression of the ORDER BY pTerm */
    CollSeq *pColl;    /* The collating sequence of pExpr */
    int iColumn;       /* The i-th column of the index.  -1 for rowid */
    const char *zColl; /* Name of the collating sequence for i-th index term */

    /* Can not use an index sort on anything that is not a column in the
    ** left-most table of the FROM clause. Break out of the loop if this
    ** expression is anything other than that. */
    pTerm = &pOrderBy->a[iTerm];
    pExpr = pTerm->pExpr;
    if( pExpr->op!=TK_COLUMN || pExpr->iTable!=base ) break;
    iColumn = pExpr->iColumn;

    /* Check that column iColumn is a part of the index. If it is not, then
    ** this index may not be used as a sorting index. This block also checks
    ** that column iColumn is either the iNext'th column of the index, or
    ** else one of the nEqCol columns that the index guarantees will be 
    ** constant.  */
    for(iIdxCol=0; iIdxCol<nIdxCol; iIdxCol++){
      if( idxColumnNumber(pIdx, pPk, iIdxCol)==iColumn ) break;
    }
    if( iIdxCol==nIdxCol || (iIdxCol>=nEqCol && iIdxCol!=iNext) ) break;

    /* Check that the collation sequence used by the expression is the same
    ** as the collation sequence used by the index. If not, this is not a
    ** sorting index.  */
    pColl = sqlite4ExprCollSeq(pParse, pExpr);
    if( !pColl ) pColl = db->pDfltColl;
    if( iIdxCol<pIdx->nColumn ){
      zColl = pIdx->azColl[iIdxCol];
    }else if( iColumn>=0 ) {
      zColl = pTab->aCol[iColumn].zColl;
    }else{
      zColl = 0;
    }
    if( pColl!=sqlite4FindCollSeq(db, zColl, 0) ) break;

    if( iIdxCol==iNext ){
      u8 reqSortOrder;
      u8 idxSortOrder = SQLITE4_SO_ASC;
      if( iIdxCol<pIdx->nColumn ) idxSortOrder = pIdx->aSortOrder[iIdxCol];
      assert( idxSortOrder==SQLITE4_SO_ASC || idxSortOrder==SQLITE4_SO_DESC );

      reqSortOrder = (idxSortOrder ^ pTerm->sortOrder);
      if( iNext==nEqCol ){
        sortOrder = reqSortOrder;
      }else if( sortOrder!=reqSortOrder ){
        break;
      }
      iNext++;
    }

#if 0
    if( iColumn<0 && !referencesOtherTables(pOrderBy, pMaskSet, j, base) ){
      /* If the indexed column is the primary key and everything matches
      ** so far and none of the ORDER BY terms to the right reference other
      ** tables in the join, then we are assured that the index can be used 
      ** to sort because the primary key is unique and so none of the other
      ** columns will make any difference
      */


      j = nTerm;



    }
#endif


  }

  *pbRev = sortOrder!=0;

  if( iTerm>=nTerm ){
    /* All terms of the ORDER BY clause are covered by this index. The
    ** index can therefore be used for sorting.  */
    return 1;
  }




  if( pIdx->onError!=OE_None



   && iNext>=pIdx->nColumn 
   && (wsFlags & WHERE_COLUMN_NULL)==0
   && !referencesOtherTables(pOrderBy, pMaskSet, iTerm, base) 
  ){

    if( iNext==nIdxCol ){
      /* All columns indexed by this UNIQUE index, and all PK columns are
      ** are matched by a prefix of the ORDER BY clause. And since the PK
      ** columns are guaranteed to be unique and NOT NULL, there is no way
      ** for the trailing ORDER BY terms to affect the sort order. Therefore,
      ** we have a sorting index.  */
      return 1;
    }else{
      int i;
      for(i=nEqCol; i<pIdx->nColumn; i++){
        int iCol = pIdx->aiColumn[i];
        if( iCol>=0 && pTab->aCol[iCol].notNull==0 ) break;
      }

      /* All columns indexed by this UNIQUE index are matched by a prefix
      ** of the ORDER BY clause. And there is reason to believe that none
      ** of the expressions in the ORDER BY prefix will evalulate to NULL.
      ** The index may be used for sorting in this case too since it is
      ** guaranteed that none of the trailing, unmatched ORDER BY terms 
      ** affect the sort order.  */
      return (i>=pIdx->nColumn);
    }
  }

  return 0;
}

/*
** Prepare a crude estimate of the logarithm of the input value.
** The results need not be exact.  This is only used for estimating
** the total cost of performing operations with O(logN) or O(NlogN)
** complexity.  Because N is just a guess, it is no great tragedy if
** logN is a little off.
*/
static double estLog(double N){
  double logN = 1;
  double x = 10;
  while( N>x ){
    logN += 1;
    x *= 10;
  }
  return logN;
}

/*
** Two routines for printing the content of an sqlite4_index_info
** structure.  Used for testing and debugging only.  If neither
** SQLITE4_TEST or SQLITE4_DEBUG are defined, then these routines
** are no-ops.
*/
#if !defined(SQLITE4_OMIT_VIRTUALTABLE) && defined(SQLITE4_DEBUG)
static void TRACE_IDX_INPUTS(sqlite4_index_info *p){
  int i;
  if( !sqlite4WhereTrace ) return;
  for(i=0; i<p->nConstraint; i++){
    sqlite4DebugPrintf("  constraint[%d]: col=%d termid=%d op=%d usabled=%d\n",
       i,
       p->aConstraint[i].iColumn,







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  /* Prevent ON clause terms of a LEFT JOIN from being used to drive
  ** an index for tables to the left of the join.
  */
  pTerm->prereqRight |= extraRight;
}

/*



















** This function searches pList for a entry that matches the iCol-th column

** of index pIdx.


**
** If such an expression is found, its index in pList->a[] is returned. If
** no expression is found, -1 is returned.
*/
static int findIndexCol(
  Parse *pParse,                  /* Parse context */
  ExprList *pList,                /* Expression list to search */
  int iBase,                      /* Cursor for table associated with pIdx */
  Index *pIdx,                    /* Index to match column of */
  int iCol                        /* Column of index to match */
){
  int i;
  const char *zColl = pIdx->azColl[iCol];

  for(i=0; i<pList->nExpr; i++){
    Expr *p = sqlite4ExprSkipCollate(pList->a[i].pExpr);
    if( p->op==TK_COLUMN
     && p->iColumn==pIdx->aiColumn[iCol]
     && p->iTable==iBase
    ){
      CollSeq *pColl = sqlite4ExprCollSeq(pParse, pList->a[i].pExpr);

      if( ALWAYS(pColl) && 0==sqlite4_stricmp(pColl->zName, zColl) ){
        return i;
      }
    }
  }

  return -1;
}

/*

** Return true if the DISTINCT expression-list passed as the third argument


** is redundant.

**





















































** A DISTINCT list is redundant if the database contains some subset of
** columns that are unique and non-null.

*/
static int isDistinctRedundant(
  Parse *pParse,            /* Parsing context */
  SrcList *pTabList,        /* The FROM clause */
  WhereClause *pWC,         /* The WHERE clause */
  ExprList *pDistinct       /* The result set that needs to be DISTINCT */
){
  Table *pTab;
  Index *pIdx;
  int i;                          
  int iBase;

  /* If there is more than one table or sub-select in the FROM clause of
  ** this query, then it will not be possible to show that the DISTINCT 
  ** clause is redundant. */
  if( pTabList->nSrc!=1 ) return 0;
  iBase = pTabList->a[0].iCursor;
  pTab = pTabList->a[0].pTab;

  /* If any of the expressions is an IPK column on table iBase, then return 
  ** true. Note: The (p->iTable==iBase) part of this test may be false if the
  ** current SELECT is a correlated sub-query.
  */
  for(i=0; i<pDistinct->nExpr; i++){
    Expr *p = sqlite4ExprSkipCollate(pDistinct->a[i].pExpr);
    if( p->op==TK_COLUMN && p->iTable==iBase && p->iColumn<0 ) return 1;
  }

  /* Loop through all indices on the table, checking each to see if it makes
  ** the DISTINCT qualifier redundant. It does so if:
  **
  **   1. The index is itself UNIQUE, and
  **
  **   2. All of the columns in the index are either part of the pDistinct
  **      list, or else the WHERE clause contains a term of the form "col=X",
  **      where X is a constant value. The collation sequences of the
  **      comparison and select-list expressions must match those of the index.
  **
  **   3. All of those index columns for which the WHERE clause does not
  **      contain a "col=X" term are subject to a NOT NULL constraint.
  */
  for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
    if( pIdx->onError==OE_None ) continue;
    for(i=0; i<pIdx->nColumn; i++){
      int iCol = pIdx->aiColumn[i];
      if( 0==findTerm(pWC, iBase, iCol, ~(Bitmask)0, WO_EQ, pIdx) ){
        int iIdxCol = findIndexCol(pParse, pDistinct, iBase, pIdx, i);
        if( iIdxCol<0 || pTab->aCol[pIdx->aiColumn[i]].notNull==0 ){
          break;
        }
      }
    }
    if( i==pIdx->nColumn ){
      /* This index implies that the DISTINCT qualifier is redundant. */
      return 1;
    }
  }

  return 0;
}


/* 






















** The (an approximate) sum of two WhereCosts.  This computation is








** not a simple "+" operator because WhereCost is stored as a logarithmic




** value.



** 









*/
static WhereCost whereCostAdd(WhereCost a, WhereCost b){
  static const unsigned char x[] = {

     10, 10,                         /* 0,1 */
      9, 9,                          /* 2,3 */

      8, 8,                          /* 4,5 */
      7, 7, 7,                       /* 6,7,8 */



      6, 6, 6,                       /* 9,10,11 */
      5, 5, 5,                       /* 12-14 */
      4, 4, 4, 4,                    /* 15-18 */
      3, 3, 3, 3, 3, 3,              /* 19-24 */
      2, 2, 2, 2, 2, 2, 2,           /* 25-31 */


  };
  if( a>=b ){
    if( a>b+49 ) return a;
    if( a>b+31 ) return a+1;
    return a+x[a-b];
  }else{




    if( b>a+49 ) return b;


    if( b>a+31 ) return b+1;



    return b+x[b-a];




  }







}









/*













** Convert an integer into a WhereCost.  In other words, compute a





** good approximatation for 10*log2(x).
















*/
static WhereCost whereCost(tRowcnt x){
  static WhereCost a[] = { 0, 2, 3, 5, 6, 7, 8, 9 };
  WhereCost y = 40;
  if( x<8 ){
    if( x<2 ) return 0;
    while( x<8 ){  y -= 10; x <<= 1; }
  }else{

    while( x>255 ){ y += 40; x >>= 4; }
    while( x>15 ){  y += 10; x >>= 1; }
  }
  return a[x&7] + y - 10;

}





#ifndef SQLITE4_OMIT_VIRTUALTABLE
/*
** Convert a double (as received from xBestIndex of a virtual table)
** into a WhereCost.  In other words, compute an approximation for
** 10*log2(x).
*/
static WhereCost whereCostFromDouble(double x){
  u64 a;
  WhereCost e;



  assert( sizeof(x)==8 && sizeof(a)==8 );
  if( x<=1 ) return 0;
  if( x<=2000000000 ) return whereCost((tRowcnt)x);
  memcpy(&a, &x, 8);
  e = (a>>52) - 1022;


  return e*10;





}
#endif /* SQLITE4_OMIT_VIRTUALTABLE */













/*
** Estimate the logarithm of the input value to base 2.




*/
static WhereCost estLog(WhereCost N){

  WhereCost x = whereCost(N);




  return x>33 ? x - 33 : 0;
}

/*
** Two routines for printing the content of an sqlite4_index_info
** structure.  Used for testing and debugging only.  If neither
** SQLITE4_TEST or SQLITE4_DEBUG are defined, then these routines
** are no-ops.
*/
#if !defined(SQLITE4_OMIT_VIRTUALTABLE) && defined(WHERETRACE_ENABLED)
static void TRACE_IDX_INPUTS(sqlite4_index_info *p){
  int i;
  if( !sqlite4WhereTrace ) return;
  for(i=0; i<p->nConstraint; i++){
    sqlite4DebugPrintf("  constraint[%d]: col=%d termid=%d op=%d usabled=%d\n",
       i,
       p->aConstraint[i].iColumn,
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966

1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076


2077

2078
2079


2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091

2092
2093
2094
2095
2096
2097
2098






2099

2100
2101
2102
2103
2104
2105



2106


















2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129


2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141


















2142
2143
2144

2145
2146
2147
2148
2149

2150
2151
2152
2153
2154
2155

2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206

2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242

2243
2244
2245
2246
2247
2248
2249
2250


2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
  sqlite4DebugPrintf("  estimatedCost=%g\n", p->estimatedCost);
}
#else
#define TRACE_IDX_INPUTS(A)
#define TRACE_IDX_OUTPUTS(A)
#endif

/* 
** Required because bestIndex() is called by bestOrClauseIndex() 
*/
static void bestIndex(
    Parse*, WhereClause*, SrcListItem*,
    Bitmask, Bitmask, ExprList*, WhereCost*);

/*
** This routine attempts to find an scanning strategy that can be used 
** to optimize an 'OR' expression that is part of a WHERE clause. 
**
** The table associated with FROM clause term pSrc may be either a
** regular B-Tree table or a virtual table.
*/
static void bestOrClauseIndex(
  Parse *pParse,              /* The parsing context */
  WhereClause *pWC,           /* The WHERE clause */
  SrcListItem *pSrc,  /* The FROM clause term to search */
  Bitmask notReady,           /* Mask of cursors not available for indexing */
  Bitmask notValid,           /* Cursors not available for any purpose */
  ExprList *pOrderBy,         /* The ORDER BY clause */
  WhereCost *pCost            /* Lowest cost query plan */
){
#ifndef SQLITE4_OMIT_OR_OPTIMIZATION
  const int iCur = pSrc->iCursor;   /* The cursor of the table to be accessed */
  const Bitmask maskSrc = getMask(pWC->pMaskSet, iCur);  /* Bitmask for pSrc */
  WhereTerm * const pWCEnd = &pWC->a[pWC->nTerm];        /* End of pWC->a[] */
  WhereTerm *pTerm;                 /* A single term of the WHERE clause */

  /* The OR-clause optimization is disallowed if the INDEXED BY or
  ** NOT INDEXED clauses are used or if the WHERE_AND_ONLY bit is set. */
  if( pSrc->notIndexed || pSrc->pIndex!=0 ){
    return;
  }
  if( pWC->wctrlFlags & WHERE_AND_ONLY ){
    return;
  }

  /* Search the WHERE clause terms for a usable WO_OR term. */
  for(pTerm=pWC->a; pTerm<pWCEnd; pTerm++){
    if( pTerm->eOperator==WO_OR 
     && ((pTerm->prereqAll & ~maskSrc) & notReady)==0
     && (pTerm->u.pOrInfo->indexable & maskSrc)!=0 
    ){
      WhereClause * const pOrWC = &pTerm->u.pOrInfo->wc;
      WhereTerm * const pOrWCEnd = &pOrWC->a[pOrWC->nTerm];
      WhereTerm *pOrTerm;
      int flags = WHERE_MULTI_OR;
      double rTotal = 0;
      double nRow = 0;
      Bitmask used = 0;

      for(pOrTerm=pOrWC->a; pOrTerm<pOrWCEnd; pOrTerm++){
        WhereCost sTermCost;
        WHERETRACE(("... Multi-index OR testing for term %d of %d....\n", 
          (pOrTerm - pOrWC->a), (pTerm - pWC->a)
        ));
        if( pOrTerm->eOperator==WO_AND ){
          WhereClause *pAndWC = &pOrTerm->u.pAndInfo->wc;
          bestIndex(pParse, pAndWC, pSrc, notReady, notValid, 0, &sTermCost);
        }else if( pOrTerm->leftCursor==iCur ){
          WhereClause tempWC;
          tempWC.pParse = pWC->pParse;
          tempWC.pMaskSet = pWC->pMaskSet;
          tempWC.pOuter = pWC;
          tempWC.op = TK_AND;
          tempWC.a = pOrTerm;
          tempWC.wctrlFlags = 0;
          tempWC.nTerm = 1;
          bestIndex(pParse, &tempWC, pSrc, notReady, notValid, 0, &sTermCost);
        }else{
          continue;
        }
        rTotal += sTermCost.rCost;
        nRow += sTermCost.plan.nRow;
        used |= sTermCost.used;
        if( rTotal>=pCost->rCost ) break;
      }

      /* If there is an ORDER BY clause, increase the scan cost to account 
      ** for the cost of the sort. */
      if( pOrderBy!=0 ){
        WHERETRACE(("... sorting increases OR cost %.9g to %.9g\n",
                    rTotal, rTotal+nRow*estLog(nRow)));
        rTotal += nRow*estLog(nRow);
      }

      /* If the cost of scanning using this OR term for optimization is
      ** less than the current cost stored in pCost, replace the contents
      ** of pCost. */
      WHERETRACE(("... multi-index OR cost=%.9g nrow=%.9g\n", rTotal, nRow));
      if( rTotal<pCost->rCost ){
        pCost->rCost = rTotal;
        pCost->used = used;
        pCost->plan.nRow = nRow;
        pCost->plan.wsFlags = flags;
        pCost->plan.u.pTerm = pTerm;
      }
    }
  }
#endif /* SQLITE4_OMIT_OR_OPTIMIZATION */
}

#ifndef SQLITE4_OMIT_AUTOMATIC_INDEX
/*
** Return TRUE if the WHERE clause term pTerm is of a form where it
** could be used with an index to access pSrc, assuming an appropriate
** index existed.
*/
static int termCanDriveIndex(
  WhereTerm *pTerm,              /* WHERE clause term to check */
  SrcListItem *pSrc,     /* Table we are trying to access */
  Bitmask notReady               /* Tables in outer loops of the join */
){
  char aff;
  if( pTerm->leftCursor!=pSrc->iCursor ) return 0;
  if( pTerm->eOperator!=WO_EQ ) return 0;
  if( (pTerm->prereqRight & notReady)!=0 ) return 0;

  aff = pSrc->pTab->aCol[pTerm->u.leftColumn].affinity;
  if( !sqlite4IndexAffinityOk(pTerm->pExpr, aff) ) return 0;
  return 1;
}
#endif

#ifndef SQLITE4_OMIT_AUTOMATIC_INDEX
/*
** If the query plan for pSrc specified in pCost is a full table scan
** and indexing is allows (if there is no NOT INDEXED clause) and it
** possible to construct a transient index that would perform better
** than a full table scan even when the cost of constructing the index
** is taken into account, then alter the query plan to use the
** transient index.
*/
static void bestAutomaticIndex(
  Parse *pParse,              /* The parsing context */
  WhereClause *pWC,           /* The WHERE clause */
  SrcListItem *pSrc,  /* The FROM clause term to search */
  Bitmask notReady,           /* Mask of cursors that are not available */
  WhereCost *pCost            /* Lowest cost query plan */
){
  double nTableRow;           /* Rows in the input table */
  double logN;                /* log(nTableRow) */
  double costTempIdx;         /* per-query cost of the transient index */
  WhereTerm *pTerm;           /* A single term of the WHERE clause */
  WhereTerm *pWCEnd;          /* End of pWC->a[] */
  Table *pTable;              /* Table tht might be indexed */

  if( pParse->nQueryLoop<=(double)1 ){
    /* There is no point in building an automatic index for a single scan */
    return;
  }
  if( (pParse->db->flags & SQLITE4_AutoIndex)==0 ){
    /* Automatic indices are disabled at run-time */
    return;
  }
  if( (pWC->wctrlFlags & WHERE_NO_AUTOINDEX)!=0 ){
    return;
  }
  if( (pCost->plan.wsFlags & WHERE_NOT_FULLSCAN)!=0 ){
    /* We already have some kind of index in use for this query. */
    return;
  }
  if( pSrc->notIndexed ){
    /* The NOT INDEXED clause appears in the SQL. */
    return;
  }
  if( pSrc->isCorrelated ){
    /* The source is a correlated sub-query. No point in indexing it. */
    return;
  }

  assert( pParse->nQueryLoop >= (double)1 );
  pTable = pSrc->pTab;
  nTableRow = pTable->nRowEst;
  logN = estLog(nTableRow);
  costTempIdx = 2*logN*(nTableRow/pParse->nQueryLoop + 1);
  if( costTempIdx>=pCost->rCost ){
    /* The cost of creating the transient table would be greater than
    ** doing the full table scan */
    return;
  }

  /* Search for any equality comparison term */
  pWCEnd = &pWC->a[pWC->nTerm];
  for(pTerm=pWC->a; pTerm<pWCEnd; pTerm++){
    if( termCanDriveIndex(pTerm, pSrc, notReady) ){
      WHERETRACE(("auto-index reduces cost from %.1f to %.1f\n",
                    pCost->rCost, costTempIdx));
      pCost->rCost = costTempIdx;
      pCost->plan.nRow = logN + 1;
      pCost->plan.wsFlags = WHERE_TEMP_INDEX;
      pCost->plan.u.pIdx = 0;
      pCost->used = pTerm->prereqRight;
      break;
    }
  }
}
#else
# define bestAutomaticIndex(A,B,C,D,E)  /* no-op */
#endif /* SQLITE4_OMIT_AUTOMATIC_INDEX */


#ifndef SQLITE4_OMIT_AUTOMATIC_INDEX
/*
** Generate code to construct the Index object for an automatic index
** and to set up the WhereLevel object pLevel so that the code generator
** makes use of the automatic index.
*/
static void constructAutomaticIndex(
  Parse *pParse,              /* The parsing context */
  WhereClause *pWC,           /* The WHERE clause */
  SrcListItem *pSrc,  /* The FROM clause term to get the next index */
  Bitmask notReady,           /* Mask of cursors that are not available */
  WhereLevel *pLevel          /* Write new index here */
){
  int nCol = 0;               /* Number of columns in index keys */
  WhereTerm *pTerm;           /* A single term of the WHERE clause */
  WhereTerm *pWCEnd;          /* End of pWC->a[] */
  int nByte;                  /* Byte of memory needed for pIdx */
  Index *pIdx;                /* Object describing the transient index */
  Vdbe *v;                    /* Prepared statement under construction */
  int addrOnce;               /* Address of the initialization bypass jump */
  Table *pTable;              /* The table being indexed */
  KeyInfo *pKeyinfo;          /* Key information for the index */   
  int addrRewind;             /* Top of the index fill loop */
  int regRecord;              /* Register holding an index record */
  int regKey;                 /* Register holding an index key */
  int n;                      /* Column counter */


  CollSeq *pColl;             /* Collating sequence to on a column */

  Bitmask idxCols;            /* Bitmap of columns used for indexing */
  int iPkCur = pLevel->iTabCur;   /* Primary key cursor to read data from */



  /* Generate code to skip over the creation and initialization of the
  ** transient index on 2nd and subsequent iterations of the loop. */
  v = pParse->pVdbe;
  assert( v!=0 );
  addrOnce = sqlite4CodeOnce(pParse);

  /* Count the number of columns that will be encoded into the index keys.
  ** set nCol to this value. Use the idxCols mask to ensure that the same
  ** column is not added to the index more than once.  */
  pTable = pSrc->pTab;
  pWCEnd = &pWC->a[pWC->nTerm];

  idxCols = 0;
  for(pTerm=pWC->a; pTerm<pWCEnd; pTerm++){
    if( termCanDriveIndex(pTerm, pSrc, notReady) ){
      int iCol = pTerm->u.leftColumn;
      Bitmask cMask = iCol>=BMS ? ((Bitmask)1)<<(BMS-1) : ((Bitmask)1)<<iCol;
      testcase( iCol==BMS );
      testcase( iCol==BMS-1 );






      if( (idxCols & cMask)==0 ){

        nCol++;
        idxCols |= cMask;
      }
    }
  }
  assert( nCol>0 );



  pLevel->plan.nEq = nCol;


















  pLevel->plan.wsFlags |= WHERE_COLUMN_EQ | WHERE_IDX_ONLY | WO_EQ;

  /* Construct the Index object to describe this index */
  nByte = sizeof(Index);          /* Index */
  nByte += nCol*sizeof(int);      /* Index.aiColumn */
  nByte += nCol*sizeof(char*);    /* Index.azColl */
  nByte += nCol;                  /* Index.aSortOrder */
  pIdx = sqlite4DbMallocZero(pParse->db, nByte);
  if( pIdx==0 ) return;
  pLevel->plan.u.pIdx = pIdx;
  pIdx->eIndexType = SQLITE4_INDEX_TEMP;
  pIdx->azColl = (char**)&pIdx[1];
  pIdx->aiColumn = (int*)&pIdx->azColl[nCol];
  pIdx->aSortOrder = (u8*)&pIdx->aiColumn[nCol];
  pIdx->zName = "auto-index";
  pIdx->nColumn = nCol;
  pIdx->pTable = pTable;
  n = 0;
  idxCols = 0;
  for(pTerm=pWC->a; pTerm<pWCEnd; pTerm++){
    if( termCanDriveIndex(pTerm, pSrc, notReady) ){
      int iCol = pTerm->u.leftColumn;
      Bitmask cMask = iCol>=BMS ? ((Bitmask)1)<<(BMS-1) : ((Bitmask)1)<<iCol;


      if( (idxCols & cMask)==0 ){
        Expr *pX = pTerm->pExpr;
        idxCols |= cMask;
        pIdx->aiColumn[n] = pTerm->u.leftColumn;
        pColl = sqlite4BinaryCompareCollSeq(pParse, pX->pLeft, pX->pRight);
        pIdx->azColl[n] = ALWAYS(pColl) ? pColl->zName : "BINARY";
        n++;
      }
    }
  }
  assert( (u32)n==pLevel->plan.nEq );



















  /* Open the automatic index cursor */
  pKeyinfo = sqlite4IndexKeyinfo(pParse, pIdx);
  assert( pLevel->iIdxCur>=0 );

  sqlite4VdbeAddOp3(v, OP_OpenAutoindex, pLevel->iIdxCur, 0, 0);
  sqlite4VdbeChangeP4(v, -1, (char*)pKeyinfo, P4_KEYINFO_HANDOFF);
  VdbeComment((v, "for %s", pTable->zName));

  /* Populate the automatic index */

  regRecord = sqlite4GetTempRange(pParse, 2);
  regKey = regRecord+1;
  addrRewind = sqlite4VdbeAddOp1(v, OP_Rewind, iPkCur);
  sqlite4EncodeIndexKey(pParse, 0, iPkCur, pIdx, pLevel->iIdxCur, 1, regKey);
  sqlite4VdbeAddOp2(v, OP_RowData, iPkCur, regRecord);
  sqlite4VdbeAddOp3(v, OP_IdxInsert, pLevel->iIdxCur, regRecord, regKey);

  sqlite4VdbeAddOp2(v, OP_Next, iPkCur, addrRewind+1);
  sqlite4VdbeChangeP5(v, SQLITE4_STMTSTATUS_AUTOINDEX);
  sqlite4VdbeJumpHere(v, addrRewind);
  sqlite4ReleaseTempRange(pParse, regRecord, 2);
  
  /* Jump here when skipping the initialization */
  sqlite4VdbeJumpHere(v, addrOnce);
}
#endif /* SQLITE4_OMIT_AUTOMATIC_INDEX */

#ifndef SQLITE4_OMIT_VIRTUALTABLE
/*
** Allocate and populate an sqlite4_index_info structure. It is the 
** responsibility of the caller to eventually release the structure
** by passing the pointer returned by this function to sqlite4_free().
*/
static sqlite4_index_info *allocateIndexInfo(
  Parse *pParse, 
  WhereClause *pWC,
  SrcListItem *pSrc,
  ExprList *pOrderBy
){
  int i, j;
  int nTerm;
  struct sqlite4_index_constraint *pIdxCons;
  struct sqlite4_index_orderby *pIdxOrderBy;
  struct sqlite4_index_constraint_usage *pUsage;
  WhereTerm *pTerm;
  int nOrderBy;
  sqlite4_index_info *pIdxInfo;

  WHERETRACE(("Recomputing index info for %s...\n", pSrc->pTab->zName));

  /* Count the number of possible WHERE clause constraints referring
  ** to this virtual table */
  for(i=nTerm=0, pTerm=pWC->a; i<pWC->nTerm; i++, pTerm++){
    if( pTerm->leftCursor != pSrc->iCursor ) continue;
    assert( (pTerm->eOperator&(pTerm->eOperator-1))==0 );
    testcase( pTerm->eOperator==WO_IN );
    testcase( pTerm->eOperator==WO_ISNULL );
    if( pTerm->eOperator & (WO_IN|WO_ISNULL) ) continue;
    if( pTerm->wtFlags & TERM_VNULL ) continue;
    nTerm++;
  }

  /* If the ORDER BY clause contains only columns in the current 
  ** virtual table then allocate space for the aOrderBy part of
  ** the sqlite4_index_info structure.
  */
  nOrderBy = 0;
  if( pOrderBy ){

    for(i=0; i<pOrderBy->nExpr; i++){
      Expr *pExpr = pOrderBy->a[i].pExpr;
      if( pExpr->op!=TK_COLUMN || pExpr->iTable!=pSrc->iCursor ) break;
    }
    if( i==pOrderBy->nExpr ){
      nOrderBy = pOrderBy->nExpr;
    }
  }

  /* Allocate the sqlite4_index_info structure
  */
  pIdxInfo = sqlite4DbMallocZero(pParse->db, sizeof(*pIdxInfo)
                           + (sizeof(*pIdxCons) + sizeof(*pUsage))*nTerm
                           + sizeof(*pIdxOrderBy)*nOrderBy );
  if( pIdxInfo==0 ){
    sqlite4ErrorMsg(pParse, "out of memory");
    /* (double)0 In case of SQLITE4_OMIT_FLOATING_POINT... */
    return 0;
  }

  /* Initialize the structure.  The sqlite4_index_info structure contains
  ** many fields that are declared "const" to prevent xBestIndex from
  ** changing them.  We have to do some funky casting in order to
  ** initialize those fields.
  */
  pIdxCons = (struct sqlite4_index_constraint*)&pIdxInfo[1];
  pIdxOrderBy = (struct sqlite4_index_orderby*)&pIdxCons[nTerm];
  pUsage = (struct sqlite4_index_constraint_usage*)&pIdxOrderBy[nOrderBy];
  *(int*)&pIdxInfo->nConstraint = nTerm;
  *(int*)&pIdxInfo->nOrderBy = nOrderBy;
  *(struct sqlite4_index_constraint**)&pIdxInfo->aConstraint = pIdxCons;
  *(struct sqlite4_index_orderby**)&pIdxInfo->aOrderBy = pIdxOrderBy;
  *(struct sqlite4_index_constraint_usage**)&pIdxInfo->aConstraintUsage =
                                                                   pUsage;

  for(i=j=0, pTerm=pWC->a; i<pWC->nTerm; i++, pTerm++){

    if( pTerm->leftCursor != pSrc->iCursor ) continue;
    assert( (pTerm->eOperator&(pTerm->eOperator-1))==0 );
    testcase( pTerm->eOperator==WO_IN );
    testcase( pTerm->eOperator==WO_ISNULL );
    if( pTerm->eOperator & (WO_IN|WO_ISNULL) ) continue;
    if( pTerm->wtFlags & TERM_VNULL ) continue;
    pIdxCons[j].iColumn = pTerm->u.leftColumn;
    pIdxCons[j].iTermOffset = i;


    pIdxCons[j].op = (u8)pTerm->eOperator;
    /* The direct assignment in the previous line is possible only because
    ** the WO_ and SQLITE4_INDEX_CONSTRAINT_ codes are identical.  The
    ** following asserts verify this fact. */
    assert( WO_EQ==SQLITE4_INDEX_CONSTRAINT_EQ );
    assert( WO_LT==SQLITE4_INDEX_CONSTRAINT_LT );
    assert( WO_LE==SQLITE4_INDEX_CONSTRAINT_LE );
    assert( WO_GT==SQLITE4_INDEX_CONSTRAINT_GT );
    assert( WO_GE==SQLITE4_INDEX_CONSTRAINT_GE );
    assert( WO_MATCH==SQLITE4_INDEX_CONSTRAINT_MATCH );
    assert( pTerm->eOperator & (WO_EQ|WO_LT|WO_LE|WO_GT|WO_GE|WO_MATCH) );
    j++;
  }
  for(i=0; i<nOrderBy; i++){
    Expr *pExpr = pOrderBy->a[i].pExpr;
    pIdxOrderBy[i].iColumn = pExpr->iColumn;
    pIdxOrderBy[i].desc = pOrderBy->a[i].sortOrder;
  }

  return pIdxInfo;
}

/*
** The table object reference passed as the second argument to this function
** must represent a virtual table. This function invokes the xBestIndex()
** method of the virtual table with the sqlite4_index_info pointer passed
** as the argument.
**
** If an error occurs, pParse is populated with an error message and a
** non-zero value is returned. Otherwise, 0 is returned and the output
** part of the sqlite4_index_info structure is left populated.
**
** Whether or not an error is returned, it is the responsibility of the
** caller to eventually free p->idxStr if p->needToFreeIdxStr indicates
** that this is required.
*/
static int vtabBestIndex(Parse *pParse, Table *pTab, sqlite4_index_info *p){
  sqlite4_vtab *pVtab = sqlite4GetVTable(pParse->db, pTab)->pVtab;
  int i;
  int rc;

  WHERETRACE(("xBestIndex for %s\n", pTab->zName));
  TRACE_IDX_INPUTS(p);
  rc = pVtab->pModule->xBestIndex(pVtab, p);
  TRACE_IDX_OUTPUTS(p);

  if( rc!=SQLITE4_OK ){
    if( rc==SQLITE4_NOMEM ){
      pParse->db->mallocFailed = 1;







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  sqlite4DebugPrintf("  estimatedCost=%g\n", p->estimatedCost);
}
#else
#define TRACE_IDX_INPUTS(A)
#define TRACE_IDX_OUTPUTS(A)
#endif

/*








































































































** Return TRUE if the WHERE clause term pTerm is of a form where it
** could be used with an index to access pSrc, assuming an appropriate
** index existed.
*/
static int termCanDriveIndex(
  WhereTerm *pTerm,              /* WHERE clause term to check */
  struct SrcListItem *pSrc,     /* Table we are trying to access */
  Bitmask notReady               /* Tables in outer loops of the join */
){
  char aff;
  if( pTerm->leftCursor!=pSrc->iCursor ) return 0;
  if( (pTerm->eOperator & WO_EQ)==0 ) return 0;
  if( (pTerm->prereqRight & notReady)!=0 ) return 0;
  if( pTerm->u.leftColumn<0 ) return 0;
  aff = pSrc->pTab->aCol[pTerm->u.leftColumn].affinity;
  if( !sqlite4IndexAffinityOk(pTerm->pExpr, aff) ) return 0;
  return 1;
}
















































































#ifndef SQLITE4_OMIT_AUTOMATIC_INDEX
/*
** Generate code to construct the Index object for an automatic index
** and to set up the WhereLevel object pLevel so that the code generator
** makes use of the automatic index.
*/
static void constructAutomaticIndex(
  Parse *pParse,              /* The parsing context */
  WhereClause *pWC,           /* The WHERE clause */
  struct SrcListItem *pSrc,  /* The FROM clause term to get the next index */
  Bitmask notReady,           /* Mask of cursors that are not available */
  WhereLevel *pLevel          /* Write new index here */
){
  int nColumn;                /* Number of columns in the constructed index */
  WhereTerm *pTerm;           /* A single term of the WHERE clause */
  WhereTerm *pWCEnd;          /* End of pWC->a[] */
  int nByte;                  /* Byte of memory needed for pIdx */
  Index *pIdx;                /* Object describing the transient index */
  Vdbe *v;                    /* Prepared statement under construction */
  int addrInit;               /* Address of the initialization bypass jump */
  Table *pTable;              /* The table being indexed */
  KeyInfo *pKeyinfo;          /* Key information for the index */   
  int addrTop;                /* Top of the index fill loop */
  int regRecord;              /* Register holding an index record */

  int n;                      /* Column counter */
  int i;                      /* Loop counter */
  int mxBitCol;               /* Maximum column in pSrc->colUsed */
  CollSeq *pColl;             /* Collating sequence to on a column */
  WhereLoop *pLoop;           /* The Loop object */
  Bitmask idxCols;            /* Bitmap of columns used for indexing */

  Bitmask extraCols;          /* Bitmap of additional columns */
  u8 sentWarning = 0;         /* True if a warnning has been issued */

  /* Generate code to skip over the creation and initialization of the
  ** transient index on 2nd and subsequent iterations of the loop. */
  v = pParse->pVdbe;
  assert( v!=0 );
  addrInit = sqlite4CodeOnce(pParse);

  /* Count the number of columns that will be added to the index
  ** and used to match WHERE clause constraints */
  nColumn = 0;
  pTable = pSrc->pTab;
  pWCEnd = &pWC->a[pWC->nTerm];
  pLoop = pLevel->pWLoop;
  idxCols = 0;
  for(pTerm=pWC->a; pTerm<pWCEnd; pTerm++){
    if( termCanDriveIndex(pTerm, pSrc, notReady) ){
      int iCol = pTerm->u.leftColumn;
      Bitmask cMask = iCol>=BMS ? MASKBIT(BMS-1) : MASKBIT(iCol);
      testcase( iCol==BMS );
      testcase( iCol==BMS-1 );
      if( !sentWarning ){
        sqlite4_log(SQLITE4_WARNING_AUTOINDEX,
            "automatic index on %s(%s)", pTable->zName,
            pTable->aCol[iCol].zName);
        sentWarning = 1;
      }
      if( (idxCols & cMask)==0 ){
        if( whereLoopResize(pParse->db, pLoop, nColumn+1) ) return;
        pLoop->aLTerm[nColumn++] = pTerm;
        idxCols |= cMask;
      }
    }
  }
  assert( nColumn>0 );
  pLoop->u.btree.nEq = pLoop->nLTerm = nColumn;
  pLoop->wsFlags = WHERE_COLUMN_EQ | WHERE_IDX_ONLY | WHERE_INDEXED
                     | WHERE_AUTO_INDEX;

  /* Count the number of additional columns needed to create a
  ** covering index.  A "covering index" is an index that contains all
  ** columns that are needed by the query.  With a covering index, the
  ** original table never needs to be accessed.  Automatic indices must
  ** be a covering index because the index will not be updated if the
  ** original table changes and the index and table cannot both be used
  ** if they go out of sync.
  */
  extraCols = pSrc->colUsed & (~idxCols | MASKBIT(BMS-1));
  mxBitCol = (pTable->nCol >= BMS-1) ? BMS-1 : pTable->nCol;
  testcase( pTable->nCol==BMS-1 );
  testcase( pTable->nCol==BMS-2 );
  for(i=0; i<mxBitCol; i++){
    if( extraCols & MASKBIT(i) ) nColumn++;
  }
  if( pSrc->colUsed & MASKBIT(BMS-1) ){
    nColumn += pTable->nCol - BMS + 1;
  }
  pLoop->wsFlags |= WHERE_COLUMN_EQ | WHERE_IDX_ONLY;

  /* Construct the Index object to describe this index */
  nByte = sizeof(Index);
  nByte += nColumn*sizeof(int);     /* Index.aiColumn */
  nByte += nColumn*sizeof(char*);   /* Index.azColl */
  nByte += nColumn;                 /* Index.aSortOrder */
  pIdx = sqlite4DbMallocZero(pParse->db, nByte);
  if( pIdx==0 ) return;
  pLoop->u.btree.pIndex = pIdx;

  pIdx->azColl = (char**)&pIdx[1];
  pIdx->aiColumn = (int*)&pIdx->azColl[nColumn];
  pIdx->aSortOrder = (u8*)&pIdx->aiColumn[nColumn];
  pIdx->zName = "auto-index";
  pIdx->nColumn = nColumn;
  pIdx->pTable = pTable;
  n = 0;
  idxCols = 0;
  for(pTerm=pWC->a; pTerm<pWCEnd; pTerm++){
    if( termCanDriveIndex(pTerm, pSrc, notReady) ){
      int iCol = pTerm->u.leftColumn;
      Bitmask cMask = iCol>=BMS ? MASKBIT(BMS-1) : MASKBIT(iCol);
      testcase( iCol==BMS-1 );
      testcase( iCol==BMS );
      if( (idxCols & cMask)==0 ){
        Expr *pX = pTerm->pExpr;
        idxCols |= cMask;
        pIdx->aiColumn[n] = pTerm->u.leftColumn;
        pColl = sqlite4BinaryCompareCollSeq(pParse, pX->pLeft, pX->pRight);
        pIdx->azColl[n] = ALWAYS(pColl) ? pColl->zName : "BINARY";
        n++;
      }
    }
  }
  assert( (u32)n==pLoop->u.btree.nEq );

  /* Add additional columns needed to make the automatic index into
  ** a covering index */
  for(i=0; i<mxBitCol; i++){
    if( extraCols & MASKBIT(i) ){
      pIdx->aiColumn[n] = i;
      pIdx->azColl[n] = "BINARY";
      n++;
    }
  }
  if( pSrc->colUsed & MASKBIT(BMS-1) ){
    for(i=BMS-1; i<pTable->nCol; i++){
      pIdx->aiColumn[n] = i;
      pIdx->azColl[n] = "BINARY";
      n++;
    }
  }
  assert( n==nColumn );

  /* Create the automatic index */
  pKeyinfo = sqlite4IndexKeyinfo(pParse, pIdx);
  assert( pLevel->iIdxCur>=0 );
  pLevel->iIdxCur = pParse->nTab++;
  sqlite4VdbeAddOp4(v, OP_OpenAutoindex, pLevel->iIdxCur, nColumn+1, 0,
                    (char*)pKeyinfo, P4_KEYINFO_HANDOFF);
  VdbeComment((v, "for %s", pTable->zName));

  /* Fill the automatic index with content */
  addrTop = sqlite4VdbeAddOp1(v, OP_Rewind, pLevel->iTabCur);
  regRecord = sqlite4GetTempReg(pParse);


  sqlite4GenerateIndexKey(pParse, pIdx, pLevel->iTabCur, regRecord, 1);

  sqlite4VdbeAddOp2(v, OP_IdxInsert, pLevel->iIdxCur, regRecord);
  sqlite4VdbeChangeP5(v, OPFLAG_USESEEKRESULT);
  sqlite4VdbeAddOp2(v, OP_Next, pLevel->iTabCur, addrTop+1);
  sqlite4VdbeChangeP5(v, SQLITE4_STMTSTATUS_AUTOINDEX);
  sqlite4VdbeJumpHere(v, addrTop);
  sqlite4ReleaseTempReg(pParse, regRecord);
  
  /* Jump here when skipping the initialization */
  sqlite4VdbeJumpHere(v, addrInit);
}
#endif /* SQLITE4_OMIT_AUTOMATIC_INDEX */

#ifndef SQLITE4_OMIT_VIRTUALTABLE
/*
** Allocate and populate an sqlite4_index_info structure. It is the 
** responsibility of the caller to eventually release the structure
** by passing the pointer returned by this function to sqlite4_free().
*/
static sqlite4_index_info *allocateIndexInfo(
  Parse *pParse,
  WhereClause *pWC,
  struct SrcListItem *pSrc,
  ExprList *pOrderBy
){
  int i, j;
  int nTerm;
  struct sqlite4_index_constraint *pIdxCons;
  struct sqlite4_index_orderby *pIdxOrderBy;
  struct sqlite4_index_constraint_usage *pUsage;
  WhereTerm *pTerm;
  int nOrderBy;
  sqlite4_index_info *pIdxInfo;



  /* Count the number of possible WHERE clause constraints referring
  ** to this virtual table */
  for(i=nTerm=0, pTerm=pWC->a; i<pWC->nTerm; i++, pTerm++){
    if( pTerm->leftCursor != pSrc->iCursor ) continue;
    assert( IsPowerOfTwo(pTerm->eOperator & ~WO_EQUIV) );
    testcase( pTerm->eOperator & WO_IN );
    testcase( pTerm->eOperator & WO_ISNULL );
    if( pTerm->eOperator & (WO_ISNULL) ) continue;
    if( pTerm->wtFlags & TERM_VNULL ) continue;
    nTerm++;
  }

  /* If the ORDER BY clause contains only columns in the current 
  ** virtual table then allocate space for the aOrderBy part of
  ** the sqlite4_index_info structure.
  */
  nOrderBy = 0;
  if( pOrderBy ){
    int n = pOrderBy->nExpr;
    for(i=0; i<n; i++){
      Expr *pExpr = pOrderBy->a[i].pExpr;
      if( pExpr->op!=TK_COLUMN || pExpr->iTable!=pSrc->iCursor ) break;
    }
    if( i==n){
      nOrderBy = n;
    }
  }

  /* Allocate the sqlite4_index_info structure
  */
  pIdxInfo = sqlite4DbMallocZero(pParse->db, sizeof(*pIdxInfo)
                           + (sizeof(*pIdxCons) + sizeof(*pUsage))*nTerm
                           + sizeof(*pIdxOrderBy)*nOrderBy );
  if( pIdxInfo==0 ){
    sqlite4ErrorMsg(pParse, "out of memory");

    return 0;
  }

  /* Initialize the structure.  The sqlite4_index_info structure contains
  ** many fields that are declared "const" to prevent xBestIndex from
  ** changing them.  We have to do some funky casting in order to
  ** initialize those fields.
  */
  pIdxCons = (struct sqlite4_index_constraint*)&pIdxInfo[1];
  pIdxOrderBy = (struct sqlite4_index_orderby*)&pIdxCons[nTerm];
  pUsage = (struct sqlite4_index_constraint_usage*)&pIdxOrderBy[nOrderBy];
  *(int*)&pIdxInfo->nConstraint = nTerm;
  *(int*)&pIdxInfo->nOrderBy = nOrderBy;
  *(struct sqlite4_index_constraint**)&pIdxInfo->aConstraint = pIdxCons;
  *(struct sqlite4_index_orderby**)&pIdxInfo->aOrderBy = pIdxOrderBy;
  *(struct sqlite4_index_constraint_usage**)&pIdxInfo->aConstraintUsage =
                                                                   pUsage;

  for(i=j=0, pTerm=pWC->a; i<pWC->nTerm; i++, pTerm++){
    u8 op;
    if( pTerm->leftCursor != pSrc->iCursor ) continue;
    assert( IsPowerOfTwo(pTerm->eOperator & ~WO_EQUIV) );
    testcase( pTerm->eOperator & WO_IN );
    testcase( pTerm->eOperator & WO_ISNULL );
    if( pTerm->eOperator & (WO_ISNULL) ) continue;
    if( pTerm->wtFlags & TERM_VNULL ) continue;
    pIdxCons[j].iColumn = pTerm->u.leftColumn;
    pIdxCons[j].iTermOffset = i;
    op = (u8)pTerm->eOperator & WO_ALL;
    if( op==WO_IN ) op = WO_EQ;
    pIdxCons[j].op = op;
    /* The direct assignment in the previous line is possible only because
    ** the WO_ and SQLITE4_INDEX_CONSTRAINT_ codes are identical.  The
    ** following asserts verify this fact. */
    assert( WO_EQ==SQLITE4_INDEX_CONSTRAINT_EQ );
    assert( WO_LT==SQLITE4_INDEX_CONSTRAINT_LT );
    assert( WO_LE==SQLITE4_INDEX_CONSTRAINT_LE );
    assert( WO_GT==SQLITE4_INDEX_CONSTRAINT_GT );
    assert( WO_GE==SQLITE4_INDEX_CONSTRAINT_GE );
    assert( WO_MATCH==SQLITE4_INDEX_CONSTRAINT_MATCH );
    assert( pTerm->eOperator & (WO_IN|WO_EQ|WO_LT|WO_LE|WO_GT|WO_GE|WO_MATCH) );
    j++;
  }
  for(i=0; i<nOrderBy; i++){
    Expr *pExpr = pOrderBy->a[i].pExpr;
    pIdxOrderBy[i].iColumn = pExpr->iColumn;
    pIdxOrderBy[i].desc = pOrderBy->a[i].sortOrder;
  }

  return pIdxInfo;
}

/*
** The table object reference passed as the second argument to this function
** must represent a virtual table. This function invokes the xBestIndex()
** method of the virtual table with the sqlite4_index_info object that
** comes in as the 3rd argument to this function.
**
** If an error occurs, pParse is populated with an error message and a
** non-zero value is returned. Otherwise, 0 is returned and the output
** part of the sqlite4_index_info structure is left populated.
**
** Whether or not an error is returned, it is the responsibility of the
** caller to eventually free p->idxStr if p->needToFreeIdxStr indicates
** that this is required.
*/
static int vtabBestIndex(Parse *pParse, Table *pTab, sqlite4_index_info *p){
  sqlite4_vtab *pVtab = sqlite4GetVTable(pParse->db, pTab)->pVtab;
  int i;
  int rc;


  TRACE_IDX_INPUTS(p);
  rc = pVtab->pModule->xBestIndex(pVtab, p);
  TRACE_IDX_OUTPUTS(p);

  if( rc!=SQLITE4_OK ){
    if( rc==SQLITE4_NOMEM ){
      pParse->db->mallocFailed = 1;
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      sqlite4ErrorMsg(pParse, 
          "table %s: xBestIndex returned an invalid plan", pTab->zName);
    }
  }

  return pParse->nErr;
}


/*
** Compute the best index for a virtual table.
**
** The best index is computed by the xBestIndex method of the virtual
** table module.  This routine is really just a wrapper that sets up
** the sqlite4_index_info structure that is used to communicate with
** xBestIndex.
**
** In a join, this routine might be called multiple times for the
** same virtual table.  The sqlite4_index_info structure is created
** and initialized on the first invocation and reused on all subsequent
** invocations.  The sqlite4_index_info structure is also used when
** code is generated to access the virtual table.  The whereInfoDelete() 
** routine takes care of freeing the sqlite4_index_info structure after
** everybody has finished with it.
*/
static void bestVirtualIndex(
  Parse *pParse,                  /* The parsing context */
  WhereClause *pWC,               /* The WHERE clause */
  SrcListItem *pSrc,      /* The FROM clause term to search */
  Bitmask notReady,               /* Mask of cursors not available for index */
  Bitmask notValid,               /* Cursors not valid for any purpose */
  ExprList *pOrderBy,             /* The order by clause */
  WhereCost *pCost,               /* Lowest cost query plan */
  sqlite4_index_info **ppIdxInfo  /* Index information passed to xBestIndex */
){
  Table *pTab = pSrc->pTab;
  sqlite4_index_info *pIdxInfo;
  struct sqlite4_index_constraint *pIdxCons;
  struct sqlite4_index_constraint_usage *pUsage;
  WhereTerm *pTerm;
  int i, j;
  int nOrderBy;
  double rCost;

  /* Make sure wsFlags is initialized to some sane value. Otherwise, if the 
  ** malloc in allocateIndexInfo() fails and this function returns leaving
  ** wsFlags in an uninitialized state, the caller may behave unpredictably.
  */
  memset(pCost, 0, sizeof(*pCost));
  pCost->plan.wsFlags = WHERE_VIRTUALTABLE;

  /* If the sqlite4_index_info structure has not been previously
  ** allocated and initialized, then allocate and initialize it now.
  */
  pIdxInfo = *ppIdxInfo;
  if( pIdxInfo==0 ){
    *ppIdxInfo = pIdxInfo = allocateIndexInfo(pParse, pWC, pSrc, pOrderBy);
  }
  if( pIdxInfo==0 ){
    return;
  }

  /* At this point, the sqlite4_index_info structure that pIdxInfo points
  ** to will have been initialized, either during the current invocation or
  ** during some prior invocation.  Now we just have to customize the
  ** details of pIdxInfo for the current invocation and pass it to
  ** xBestIndex.
  */

  /* The module name must be defined. Also, by this point there must
  ** be a pointer to an sqlite4_vtab structure. Otherwise
  ** sqlite4ViewGetColumnNames() would have picked up the error. 
  */
  assert( pTab->azModuleArg && pTab->azModuleArg[0] );
  assert( sqlite4GetVTable(pParse->db, pTab) );

  /* Set the aConstraint[].usable fields and initialize all 
  ** output variables to zero.
  **
  ** aConstraint[].usable is true for constraints where the right-hand
  ** side contains only references to tables to the left of the current
  ** table.  In other words, if the constraint is of the form:
  **
  **           column = expr
  **
  ** and we are evaluating a join, then the constraint on column is 
  ** only valid if all tables referenced in expr occur to the left
  ** of the table containing column.
  **
  ** The aConstraints[] array contains entries for all constraints
  ** on the current table.  That way we only have to compute it once
  ** even though we might try to pick the best index multiple times.
  ** For each attempt at picking an index, the order of tables in the
  ** join might be different so we have to recompute the usable flag
  ** each time.
  */
  pIdxCons = *(struct sqlite4_index_constraint**)&pIdxInfo->aConstraint;
  pUsage = pIdxInfo->aConstraintUsage;
  for(i=0; i<pIdxInfo->nConstraint; i++, pIdxCons++){
    j = pIdxCons->iTermOffset;
    pTerm = &pWC->a[j];
    pIdxCons->usable = (pTerm->prereqRight&notReady) ? 0 : 1;
  }
  memset(pUsage, 0, sizeof(pUsage[0])*pIdxInfo->nConstraint);
  if( pIdxInfo->needToFreeIdxStr ){
    sqlite4_free(pIdxInfo->idxStr);
  }
  pIdxInfo->idxStr = 0;
  pIdxInfo->idxNum = 0;
  pIdxInfo->needToFreeIdxStr = 0;
  pIdxInfo->orderByConsumed = 0;
  /* ((double)2) In case of SQLITE4_OMIT_FLOATING_POINT... */
  pIdxInfo->estimatedCost = SQLITE4_BIG_DBL / ((double)2);
  nOrderBy = pIdxInfo->nOrderBy;
  if( !pOrderBy ){
    pIdxInfo->nOrderBy = 0;
  }

  if( vtabBestIndex(pParse, pTab, pIdxInfo) ){
    return;
  }

  pIdxCons = *(struct sqlite4_index_constraint**)&pIdxInfo->aConstraint;
  for(i=0; i<pIdxInfo->nConstraint; i++){
    if( pUsage[i].argvIndex>0 ){
      pCost->used |= pWC->a[pIdxCons[i].iTermOffset].prereqRight;
    }
  }

  /* If there is an ORDER BY clause, and the selected virtual table index
  ** does not satisfy it, increase the cost of the scan accordingly. This
  ** matches the processing for non-virtual tables in bestKVIndex().
  */
  rCost = pIdxInfo->estimatedCost;
  if( pOrderBy && pIdxInfo->orderByConsumed==0 ){
    rCost += estLog(rCost)*rCost;
  }

  /* The cost is not allowed to be larger than SQLITE4_BIG_DBL (the
  ** inital value of lowestCost in this loop. If it is, then the
  ** (cost<lowestCost) test below will never be true.
  ** 
  ** Use "(double)2" instead of "2.0" in case OMIT_FLOATING_POINT 
  ** is defined.
  */
  if( (SQLITE4_BIG_DBL/((double)2))<rCost ){
    pCost->rCost = (SQLITE4_BIG_DBL/((double)2));
  }else{
    pCost->rCost = rCost;
  }
  pCost->plan.u.pVtabIdx = pIdxInfo;
  if( pIdxInfo->orderByConsumed ){
    pCost->plan.wsFlags |= WHERE_ORDERBY;
  }
  pCost->plan.nEq = 0;
  pIdxInfo->nOrderBy = nOrderBy;

  /* Try to find a more efficient access pattern by using multiple indexes
  ** to optimize an OR expression within the WHERE clause. 
  */
  bestOrClauseIndex(pParse, pWC, pSrc, notReady, notValid, pOrderBy, pCost);
}
#endif /* SQLITE4_OMIT_VIRTUALTABLE */

#ifdef SQLITE4_ENABLE_STAT3
/*
** Estimate the location of a particular key among all keys in an
** index.  Store the results in aStat as follows:
**
**    aStat[0]      Est. number of rows less than pVal
**    aStat[1]      Est. number of rows equal to pVal
**
** Return SQLITE4_OK on success.
*/
static int whereKeyStats(
  Parse *pParse,              /* Database connection */
  Index *pIdx,                /* Index to consider domain of */
  sqlite4_buffer *pBuf,       /* Buffer containing encoded value to consider */
  int roundUp,                /* Round up if true.  Round down if false */
  tRowcnt *aStat              /* OUT: stats written here */
){
  tRowcnt n;
  IndexSample *aSample;
  int i;
  int isEq = 0;



  assert( roundUp==0 || roundUp==1 );
  assert( pIdx->nSample>0 );
  assert( pBuf->n>0 );

  n = pIdx->aiRowEst[0];
  aSample = pIdx->aSample;













  /* Set variable i to the index of the first sample equal to or larger 



  ** than the value in pBuf. Set isEq to true if the value is equal, or




  ** false otherwise.  */

  for(i=0; i<pIdx->nSample; i++){









    int res;



    int n = pBuf->n;




    if( n>aSample[i].nVal ) n = aSample[i].nVal;
























    res = memcmp(pBuf->p, aSample[i].aVal, n);


    if( res==0 ) res = pBuf->n - aSample[i].nVal;



















    if( res<=0 ){
      isEq = (res==0);
      break;


    }
  }

  /* At this point, aSample[i] is the first sample that is greater than
  ** or equal to pVal.  Or if i==pIdx->nSample, then all samples are less
  ** than pVal.  If aSample[i]==pVal, then isEq==1.
  */







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      sqlite4ErrorMsg(pParse, 
          "table %s: xBestIndex returned an invalid plan", pTab->zName);
    }
  }

  return pParse->nErr;
}
#endif /* !defined(SQLITE4_OMIT_VIRTUALTABLE) */




























































































































































#ifdef SQLITE4_ENABLE_STAT3
/*
** Estimate the location of a particular key among all keys in an
** index.  Store the results in aStat as follows:
**
**    aStat[0]      Est. number of rows less than pVal
**    aStat[1]      Est. number of rows equal to pVal
**
** Return SQLITE4_OK on success.
*/
static int whereKeyStats(
  Parse *pParse,              /* Database connection */
  Index *pIdx,                /* Index to consider domain of */
  sqlite4_value *pVal,        /* Value to consider */
  int roundUp,                /* Round up if true.  Round down if false */
  tRowcnt *aStat              /* OUT: stats written here */
){
  tRowcnt n;
  IndexSample *aSample;
  int i, eType;
  int isEq = 0;
  i64 v;
  double r, rS;

  assert( roundUp==0 || roundUp==1 );
  assert( pIdx->nSample>0 );

  if( pVal==0 ) return SQLITE4_ERROR;
  n = pIdx->aiRowEst[0];
  aSample = pIdx->aSample;
  eType = sqlite4_value_type(pVal);

  if( eType==SQLITE4_INTEGER ){
    v = sqlite4_value_int64(pVal);
    r = (i64)v;
    for(i=0; i<pIdx->nSample; i++){
      if( aSample[i].eType==SQLITE4_NULL ) continue;
      if( aSample[i].eType>=SQLITE4_TEXT ) break;
      if( aSample[i].eType==SQLITE4_INTEGER ){
        if( aSample[i].u.i>=v ){
          isEq = aSample[i].u.i==v;
          break;
        }

      }else{
        assert( aSample[i].eType==SQLITE4_FLOAT );
        if( aSample[i].u.r>=r ){
          isEq = aSample[i].u.r==r;
          break;
        }
      }
    }
  }else if( eType==SQLITE4_FLOAT ){
    r = sqlite4_value_double(pVal);
    for(i=0; i<pIdx->nSample; i++){
      if( aSample[i].eType==SQLITE4_NULL ) continue;
      if( aSample[i].eType>=SQLITE4_TEXT ) break;
      if( aSample[i].eType==SQLITE4_FLOAT ){
        rS = aSample[i].u.r;
      }else{
        rS = aSample[i].u.i;
      }
      if( rS>=r ){
        isEq = rS==r;
        break;
      }
    }
  }else if( eType==SQLITE4_NULL ){
    i = 0;
    if( aSample[0].eType==SQLITE4_NULL ) isEq = 1;
  }else{
    assert( eType==SQLITE4_TEXT || eType==SQLITE4_BLOB );
    for(i=0; i<pIdx->nSample; i++){
      if( aSample[i].eType==SQLITE4_TEXT || aSample[i].eType==SQLITE4_BLOB ){
        break;
      }
    }
    if( i<pIdx->nSample ){      
      sqlite4 *db = pParse->db;
      CollSeq *pColl;
      const u8 *z;
      if( eType==SQLITE4_BLOB ){
        z = (const u8 *)sqlite4_value_blob(pVal);
        pColl = db->pDfltColl;
        assert( pColl->enc==SQLITE4_UTF8 );
      }else{
        pColl = sqlite4GetCollSeq(pParse, SQLITE4_UTF8, 0, *pIdx->azColl);
        /* If the collating sequence was unavailable, we should have failed
        ** long ago and never reached this point.  But we'll check just to
        ** be doubly sure. */
        if( NEVER(pColl==0) ) return SQLITE4_ERROR;
        z = (const u8 *)sqlite4ValueText(pVal, pColl->enc);
        if( !z ){
          return SQLITE4_NOMEM;
        }
        assert( z && pColl && pColl->xCmp );
      }
      n = sqlite4ValueBytes(pVal, pColl->enc);
  
      for(; i<pIdx->nSample; i++){
        int c;
        int eSampletype = aSample[i].eType;
        if( eSampletype<eType ) continue;
        if( eSampletype!=eType ) break;
#ifndef SQLITE4_OMIT_UTF16
        if( pColl->enc!=SQLITE4_UTF8 ){
          int nSample;
          char *zSample = sqlite4Utf8to16(
              db, pColl->enc, aSample[i].u.z, aSample[i].nByte, &nSample
          );
          if( !zSample ){
            assert( db->mallocFailed );
            return SQLITE4_NOMEM;
          }
          c = pColl->xCmp(pColl->pUser, nSample, zSample, n, z);
          sqlite4DbFree(db, zSample);
        }else
#endif
        {
          c = pColl->xCmp(pColl->pUser, aSample[i].nByte, aSample[i].u.z, n, z);
        }
        if( c>=0 ){
          if( c==0 ) isEq = 1;
          break;
        }
      }
    }
  }

  /* At this point, aSample[i] is the first sample that is greater than
  ** or equal to pVal.  Or if i==pIdx->nSample, then all samples are less
  ** than pVal.  If aSample[i]==pVal, then isEq==1.
  */
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    aStat[0] = iLower + iGap;
  }
  return SQLITE4_OK;
}
#endif /* SQLITE4_ENABLE_STAT3 */

/*
** If expression pExpr represents a literal value, extract it and apply
** the affinity aff to it. Then encode the value using the database index
** key encoding and write the result into buffer pBuf.


**
** If the current parse is a recompile (sqlite4Reprepare()) and pExpr
** is an SQL variable that currently has a non-NULL value bound to it,
** do the same with the bound value.

**
** If neither of the above apply, leave the buffer empty.
**
** If an error occurs, return an error code. Otherwise, SQLITE4_OK.
*/
#ifdef SQLITE4_ENABLE_STAT3
static int valueFromExpr(
  Parse *pParse,                  /* Parse context */
  KeyInfo *pKeyinfo,              /* Collation sequence and sort order */
  Expr *pExpr,                    /* Expression to extract value from */
  u8 aff,                         /* Affinity to apply to value */
  sqlite4_buffer *pBuf            /* Buffer to populate */
){
  int rc = SQLITE4_OK;
  sqlite4 *db = pParse->db;
  sqlite4_value *pVal = 0;

  assert( pBuf->n==0 );

  if( pExpr->op==TK_VARIABLE
   || (pExpr->op==TK_REGISTER && pExpr->op2==TK_VARIABLE)
  ){
    int iVar = pExpr->iColumn;
    sqlite4VdbeSetVarmask(pParse->pVdbe, iVar);
    pVal = sqlite4VdbeGetValue(pParse->pReprepare, iVar, aff);
  }else{
    rc = sqlite4ValueFromExpr(db, pExpr, SQLITE4_UTF8, aff, &pVal);
  }

  if( pVal && rc==SQLITE4_OK ){
    u8 *aOut;
    int nOut;
    rc = sqlite4VdbeEncodeKey(db, pVal, 1, 2, -1, pKeyinfo, &aOut, &nOut, 0);
    if( rc==SQLITE4_OK ){
      rc = sqlite4_buffer_set(pBuf, aOut, nOut);
    }
    sqlite4DbFree(db, aOut);
  }

  sqlite4ValueFree(pVal);
  return SQLITE4_OK;
}
#endif

static int whereSampleKeyinfo(Parse *pParse, Index *p, KeyInfo *pKeyInfo){
  CollSeq *pColl;
  memset(pKeyInfo, 0, sizeof(KeyInfo));
  pKeyInfo->db = pParse->db;
  pKeyInfo->enc = SQLITE4_UTF8;
  pKeyInfo->nField = p->nColumn;
  pKeyInfo->nPK = 1;
  pKeyInfo->nData = 0;
  pKeyInfo->aSortOrder = p->aSortOrder;
  pKeyInfo->aColl[0] = pColl = sqlite4LocateCollSeq(pParse, p->azColl[0]);
  pKeyInfo->aColl[0] = pColl;
  return pColl ? SQLITE4_OK : SQLITE4_ERROR;
}

/*
** This function is used to estimate the number of rows that will be visited
** by scanning an index for a range of values. The range may have an upper
** bound, a lower bound, or both. The WHERE clause terms that set the upper
** and lower bounds are represented by pLower and pUpper respectively. For
** example, assuming that index p is on t1(a):
**







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<
<
<
<
<
<
<
<
<







2568
2569
2570
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2573
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2586
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2591
2592

2593
2594
2595
2596






2597
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2600
2601
2602








2603

2604


2605


2606
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2608














2609
2610
2611
2612
2613
2614
2615
    aStat[0] = iLower + iGap;
  }
  return SQLITE4_OK;
}
#endif /* SQLITE4_ENABLE_STAT3 */

/*
** If expression pExpr represents a literal value, set *pp to point to
** an sqlite4_value structure containing the same value, with affinity
** aff applied to it, before returning. It is the responsibility of the 
** caller to eventually release this structure by passing it to 
** sqlite4ValueFree().
**
** If the current parse is a recompile (sqlite4Reprepare()) and pExpr
** is an SQL variable that currently has a non-NULL value bound to it,
** create an sqlite4_value structure containing this value, again with
** affinity aff applied to it, instead.
**
** If neither of the above apply, set *pp to NULL.
**
** If an error occurs, return an error code. Otherwise, SQLITE4_OK.
*/
#ifdef SQLITE4_ENABLE_STAT3
static int valueFromExpr(
  Parse *pParse, 

  Expr *pExpr, 
  u8 aff, 
  sqlite4_value **pp
){






  if( pExpr->op==TK_VARIABLE
   || (pExpr->op==TK_REGISTER && pExpr->op2==TK_VARIABLE)
  ){
    int iVar = pExpr->iColumn;
    sqlite4VdbeSetVarmask(pParse->pVdbe, iVar);
    *pp = sqlite4VdbeGetValue(pParse->pReprepare, iVar, aff);








    return SQLITE4_OK;

  }


  return sqlite4ValueFromExpr(pParse->db, pExpr, SQLITE4_UTF8, aff, pp);


}
#endif















/*
** This function is used to estimate the number of rows that will be visited
** by scanning an index for a range of values. The range may have an upper
** bound, a lower bound, or both. The WHERE clause terms that set the upper
** and lower bounds are represented by pLower and pUpper respectively. For
** example, assuming that index p is on t1(a):
**
2659
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2661
2662
2663
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2665
2666
2667
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2699
2700
2701
2702
2703
2704
2705

2706
2707
2708

2709
2710
2711
2712
2713

2714
2715
2716
2717
2718
2719
2720
2721
2722
2723
2724
2725


2726


2727


2728
2729
2730
2731
2732
2733
2734
*/
static int whereRangeScanEst(
  Parse *pParse,       /* Parsing & code generating context */
  Index *p,            /* The index containing the range-compared column; "x" */
  int nEq,             /* index into p->aCol[] of the range-compared column */
  WhereTerm *pLower,   /* Lower bound on the range. ex: "x>123" Might be NULL */
  WhereTerm *pUpper,   /* Upper bound on the range. ex: "x<455" Might be NULL */
  double *pRangeDiv   /* OUT: Reduce search space by this divisor */
){
  int rc = SQLITE4_OK;

#ifdef SQLITE4_ENABLE_STAT3

  if( nEq==0 && p->nSample ){
    sqlite4 *db = pParse->db;
    KeyInfo keyinfo;
    sqlite4_buffer buf;              /* Buffer used for index sample */
    tRowcnt iLower = 0;
    tRowcnt iUpper = p->aiRowEst[0];
    tRowcnt a[2];
    u8 aff = p->pTable->aCol[p->aiColumn[0]].affinity;

    sqlite4_buffer_init(&buf, db->pEnv->pMM);
    rc = whereSampleKeyinfo(pParse, p, &keyinfo);

    if( rc==SQLITE4_OK && pLower ){
      Expr *pExpr = pLower->pExpr->pRight;
      rc = valueFromExpr(pParse, &keyinfo, pExpr, aff, &buf);
      assert( pLower->eOperator==WO_GT || pLower->eOperator==WO_GE );
      if( rc==SQLITE4_OK && buf.n
       && whereKeyStats(pParse, p, &buf, 0, a)==SQLITE4_OK
      ){
        iLower = a[0];
        if( pLower->eOperator==WO_GT ) iLower += a[1];
      }
      sqlite4_buffer_set(&buf, 0, 0);
    }
    if( rc==SQLITE4_OK && pUpper ){
      Expr *pExpr = pUpper->pExpr->pRight;
      rc = valueFromExpr(pParse, &keyinfo, pExpr, aff, &buf);
      assert( pUpper->eOperator==WO_LT || pUpper->eOperator==WO_LE );
      if( rc==SQLITE4_OK && buf.n
       && whereKeyStats(pParse, p, &buf, 1, a)==SQLITE4_OK
      ){
        iUpper = a[0];
        if( pUpper->eOperator==WO_LE ) iUpper += a[1];
      }

    }
    sqlite4_buffer_clear(&buf);
    if( rc==SQLITE4_OK ){

      if( iUpper<=iLower ){
        *pRangeDiv = (double)p->aiRowEst[0];
      }else{
        *pRangeDiv = (double)p->aiRowEst[0]/(double)(iUpper - iLower);
      }

      WHERETRACE(("range scan regions: %u..%u  div=%g\n",
                  (u32)iLower, (u32)iUpper, *pRangeDiv));
      return SQLITE4_OK;
    }
  }
#else
  UNUSED_PARAMETER(pParse);
  UNUSED_PARAMETER(p);
  UNUSED_PARAMETER(nEq);
#endif
  assert( pLower || pUpper );
  *pRangeDiv = (double)1;


  if( pLower && (pLower->wtFlags & TERM_VNULL)==0 ) *pRangeDiv *= (double)4;


  if( pUpper ) *pRangeDiv *= (double)4;


  return rc;
}

#ifdef SQLITE4_ENABLE_STAT3
/*
** Estimate the number of rows that will be returned based on
** an equality constraint x=VALUE and where that VALUE occurs in







|





|
|
<
<





<
<
<
|

|
|
|
|


|

|



|
|
|
|


|

>

<

>
|
<
<
|

>
|
|









|
>
>
|
>
>
|
>
>







2647
2648
2649
2650
2651
2652
2653
2654
2655
2656
2657
2658
2659
2660
2661


2662
2663
2664
2665
2666



2667
2668
2669
2670
2671
2672
2673
2674
2675
2676
2677
2678
2679
2680
2681
2682
2683
2684
2685
2686
2687
2688
2689
2690

2691
2692
2693


2694
2695
2696
2697
2698
2699
2700
2701
2702
2703
2704
2705
2706
2707
2708
2709
2710
2711
2712
2713
2714
2715
2716
2717
2718
2719
2720
2721
2722
2723
*/
static int whereRangeScanEst(
  Parse *pParse,       /* Parsing & code generating context */
  Index *p,            /* The index containing the range-compared column; "x" */
  int nEq,             /* index into p->aCol[] of the range-compared column */
  WhereTerm *pLower,   /* Lower bound on the range. ex: "x>123" Might be NULL */
  WhereTerm *pUpper,   /* Upper bound on the range. ex: "x<455" Might be NULL */
  WhereCost *pRangeDiv /* OUT: Reduce search space by this divisor */
){
  int rc = SQLITE4_OK;

#ifdef SQLITE4_ENABLE_STAT3

  if( nEq==0 && p->nSample && OptimizationEnabled(pParse->db, SQLITE4_Stat3) ){
    sqlite4_value *pRangeVal;


    tRowcnt iLower = 0;
    tRowcnt iUpper = p->aiRowEst[0];
    tRowcnt a[2];
    u8 aff = p->pTable->aCol[p->aiColumn[0]].affinity;




    if( pLower ){
      Expr *pExpr = pLower->pExpr->pRight;
      rc = valueFromExpr(pParse, pExpr, aff, &pRangeVal);
      assert( (pLower->eOperator & (WO_GT|WO_GE))!=0 );
      if( rc==SQLITE4_OK
       && whereKeyStats(pParse, p, pRangeVal, 0, a)==SQLITE4_OK
      ){
        iLower = a[0];
        if( (pLower->eOperator & WO_GT)!=0 ) iLower += a[1];
      }
      sqlite4ValueFree(pRangeVal);
    }
    if( rc==SQLITE4_OK && pUpper ){
      Expr *pExpr = pUpper->pExpr->pRight;
      rc = valueFromExpr(pParse, pExpr, aff, &pRangeVal);
      assert( (pUpper->eOperator & (WO_LT|WO_LE))!=0 );
      if( rc==SQLITE4_OK
       && whereKeyStats(pParse, p, pRangeVal, 1, a)==SQLITE4_OK
      ){
        iUpper = a[0];
        if( (pUpper->eOperator & WO_LE)!=0 ) iUpper += a[1];
      }
      sqlite4ValueFree(pRangeVal);
    }

    if( rc==SQLITE4_OK ){
      WhereCost iBase = whereCost(p->aiRowEst[0]);
      if( iUpper>iLower ){


        iBase -= whereCost(iUpper - iLower);
      }
      *pRangeDiv = iBase;
      WHERETRACE(0x100, ("range scan regions: %u..%u  div=%d\n",
                         (u32)iLower, (u32)iUpper, *pRangeDiv));
      return SQLITE4_OK;
    }
  }
#else
  UNUSED_PARAMETER(pParse);
  UNUSED_PARAMETER(p);
  UNUSED_PARAMETER(nEq);
#endif
  assert( pLower || pUpper );
  *pRangeDiv = 0;
  /* TUNING:  Each inequality constraint reduces the search space 4-fold.
  ** A BETWEEN operator, therefore, reduces the search space 16-fold */
  if( pLower && (pLower->wtFlags & TERM_VNULL)==0 ){
    *pRangeDiv += 20;  assert( 20==whereCost(4) );
  }
  if( pUpper ){
    *pRangeDiv += 20;  assert( 20==whereCost(4) );
  }
  return rc;
}

#ifdef SQLITE4_ENABLE_STAT3
/*
** Estimate the number of rows that will be returned based on
** an equality constraint x=VALUE and where that VALUE occurs in
2746
2747
2748
2749
2750
2751
2752
2753
2754
2755
2756
2757
2758
2759
2760
2761
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2766
2767
2768
2769
2770
2771
2772
2773
2774
2775
2776
2777
2778
2779
2780
2781
2782
2783
2784
2785
2786
2787
2788
2789
2790
2791
2792
** for a UTF conversion required for comparison.  The error is stored
** in the pParse structure.
*/
static int whereEqualScanEst(
  Parse *pParse,       /* Parsing & code generating context */
  Index *p,            /* The index whose left-most column is pTerm */
  Expr *pExpr,         /* Expression for VALUE in the x=VALUE constraint */
  double *pnRow        /* Write the revised row estimate here */
){
  sqlite4_buffer buf;
  u8 aff;                   /* Column affinity */
  int rc;                   /* Subfunction return code */
  tRowcnt a[2];             /* Statistics */

  assert( p->aSample!=0 );
  assert( p->nSample>0 );

  sqlite4_buffer_init(&buf, pParse->db->pEnv->pMM);
  aff = p->pTable->aCol[p->aiColumn[0]].affinity;
  if( pExpr ){
    KeyInfo keyinfo;
    rc = whereSampleKeyinfo(pParse, p, &keyinfo);
    if( rc==SQLITE4_OK ){
      rc = valueFromExpr(pParse, &keyinfo, pExpr, aff, &buf);
      if( buf.n==0 ) return SQLITE4_NOTFOUND;
    }
  }else{
    /* Populate the buffer with a NULL. */
    u8 aNull[2] = {0x05, 0xfa};        /* ASC, DESC */
    rc = sqlite4_buffer_set(&buf, &aNull[p->aSortOrder[0]], 1);
  }
  if( rc ) goto whereEqualScanEst_cancel;

  rc = whereKeyStats(pParse, p, &buf, 0, a);
  if( rc==SQLITE4_OK ){
    WHERETRACE(("equality scan regions: %d\n", (int)a[1]));
    *pnRow = a[1];
  }
whereEqualScanEst_cancel:
  sqlite4_buffer_clear(&buf);
  return rc;
}
#endif /* defined(SQLITE4_ENABLE_STAT3) */

#ifdef SQLITE4_ENABLE_STAT3
/*
** Estimate the number of rows that will be returned based on







|

|






<
<


<
<
<
|
|
<

<
<
|

<
|
|

|



|







2735
2736
2737
2738
2739
2740
2741
2742
2743
2744
2745
2746
2747
2748
2749
2750


2751
2752



2753
2754

2755


2756
2757

2758
2759
2760
2761
2762
2763
2764
2765
2766
2767
2768
2769
2770
2771
2772
** for a UTF conversion required for comparison.  The error is stored
** in the pParse structure.
*/
static int whereEqualScanEst(
  Parse *pParse,       /* Parsing & code generating context */
  Index *p,            /* The index whose left-most column is pTerm */
  Expr *pExpr,         /* Expression for VALUE in the x=VALUE constraint */
  tRowcnt *pnRow       /* Write the revised row estimate here */
){
  sqlite4_value *pRhs = 0;  /* VALUE on right-hand side of pTerm */
  u8 aff;                   /* Column affinity */
  int rc;                   /* Subfunction return code */
  tRowcnt a[2];             /* Statistics */

  assert( p->aSample!=0 );
  assert( p->nSample>0 );


  aff = p->pTable->aCol[p->aiColumn[0]].affinity;
  if( pExpr ){



    rc = valueFromExpr(pParse, pExpr, aff, &pRhs);
    if( rc ) goto whereEqualScanEst_cancel;

  }else{


    pRhs = sqlite4ValueNew(pParse->db);
  }

  if( pRhs==0 ) return SQLITE4_NOTFOUND;
  rc = whereKeyStats(pParse, p, pRhs, 0, a);
  if( rc==SQLITE4_OK ){
    WHERETRACE(0x100,("equality scan regions: %d\n", (int)a[1]));
    *pnRow = a[1];
  }
whereEqualScanEst_cancel:
  sqlite4ValueFree(pRhs);
  return rc;
}
#endif /* defined(SQLITE4_ENABLE_STAT3) */

#ifdef SQLITE4_ENABLE_STAT3
/*
** Estimate the number of rows that will be returned based on
2804
2805
2806
2807
2808
2809
2810
2811
2812
2813
2814
2815
2816
2817
2818
2819
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2821
2822
2823
2824
2825
2826
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2828
2829
2830
2831
2832
2833
2834
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2845
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2860
2861
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2865
2866
2867
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2873
2874
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2877
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2886
2887
2888
2889
2890
2891
2892
2893
2894
2895
2896
2897
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2908
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2911
2912
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2917
2918
2919
2920
2921
2922
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2924
2925
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2931
2932
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2935
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2937
2938
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2940
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2945
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2950
2951
2952
2953
2954
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2957
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2962
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2965
2966
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2982
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2984
2985
2986
2987
2988
2989
2990
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2994
2995
2996
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2998
2999
3000
3001
3002
3003
3004
3005
3006
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3009
3010
3011
3012
3013
3014
3015
3016
3017
3018
3019
3020
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3022
3023
3024
3025
3026
3027
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3029
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3103
3104
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3106
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3108
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3111
3112
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3114
3115
3116
3117
3118
3119
3120
3121
3122
3123
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3125
3126
3127
3128
3129
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3133
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3200
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3203
3204
3205
3206
3207
3208
3209
3210
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3214
3215
3216
3217
3218
3219
3220
3221
3222
3223
3224
3225
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3231
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3245
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3303
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3305
3306
3307
3308
3309
3310
3311
3312
3313
3314
3315
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3317
3318
3319
3320
3321
3322
3323
3324
3325
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3327
3328
3329
3330
3331
3332
3333
3334
3335
3336
3337
3338
3339
3340
3341
3342
3343
3344
3345
3346
3347
3348
3349
3350
3351
3352
3353
3354
3355
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3357
3358
3359
3360
3361
3362
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3364
3365
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3382
3383
3384
3385
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3388
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3390
3391
3392
3393
3394
3395
3396
3397
3398
3399
3400
3401
3402
3403
3404
** for a UTF conversion required for comparison.  The error is stored
** in the pParse structure.
*/
static int whereInScanEst(
  Parse *pParse,       /* Parsing & code generating context */
  Index *p,            /* The index whose left-most column is pTerm */
  ExprList *pList,     /* The value list on the RHS of "x IN (v1,v2,v3,...)" */
  double *pnRow        /* Write the revised row estimate here */
){
  int rc = SQLITE4_OK;         /* Subfunction return code */
  double nEst;                /* Number of rows for a single term */
  double nRowEst = (double)0; /* New estimate of the number of rows */
  int i;                      /* Loop counter */

  assert( p->aSample!=0 );
  for(i=0; rc==SQLITE4_OK && i<pList->nExpr; i++){
    nEst = p->aiRowEst[0];
    rc = whereEqualScanEst(pParse, p, pList->a[i].pExpr, &nEst);
    nRowEst += nEst;
  }
  if( rc==SQLITE4_OK ){
    if( nRowEst > p->aiRowEst[0] ) nRowEst = p->aiRowEst[0];
    *pnRow = nRowEst;
    WHERETRACE(("IN row estimate: est=%g\n", nRowEst));
  }
  return rc;
}
#endif /* defined(SQLITE4_ENABLE_STAT3) */

/*
** Try to find a MATCH expression that constrains the pTabItem table in the
** WHERE clause. If one exists, set *piTerm to the index in the pWC->a[] array
** and return non-zero. If no such expression exists, return 0.
*/
static int findMatchExpr(
  Parse *pParse, 
  WhereClause *pWC, 
  SrcListItem *pTabItem, 
  int *piTerm
){
  int i;
  int iCsr = pTabItem->iCursor;

  for(i=0; i<pWC->nTerm; i++){
    Expr *pMatch = pWC->a[i].pExpr;
    if( pMatch->iTable==iCsr && pMatch->op==TK_MATCH ) break;
  }
  if( i==pWC->nTerm ) return 0;

  *piTerm = i;
  return 1;
}

static int bestMatchIdx(
  Parse *pParse, 
  WhereClause *pWC, 
  SrcListItem *pTabItem, 
  Bitmask notReady, 
  WhereCost *pCost
){
  int iTerm;

  if( 0==findMatchExpr(pParse, pWC, pTabItem, &iTerm) ) return 0;

  /* Check that the MATCH expression is not composed using values from any
  ** tables that are not ready. If it does, return 0. */
  if( notReady & pWC->a[iTerm].prereqAll ) return 0;

  pCost->used = pWC->a[iTerm].prereqAll;
  pCost->rCost = 1.0;
  pCost->plan.wsFlags = WHERE_INDEXED;
  pCost->plan.nEq = 0;
  pCost->plan.nRow = 10;
  pCost->plan.u.pIdx = pWC->a[iTerm].pExpr->pIdx;
  return 1;
}

/*
** Find the best query plan for accessing a particular table.  Write the
** best query plan and its cost into the WhereCost object supplied as the
** last parameter.
**
** The lowest cost plan wins.  The cost is an estimate of the amount of
** CPU and disk I/O needed to process the requested result.
** Factors that influence cost include:
**
**    *  The estimated number of rows that will be retrieved.  (The
**       fewer the better.)
**
**    *  Whether or not sorting must occur.
**
**    *  Whether or not there must be separate lookups in the
**       index and in the main table.
**
** If there was an INDEXED BY clause (pSrc->pIndex) attached to the table in
** the SQL statement, then this function only considers plans using the 
** named index. If no such plan is found, then the returned cost is
** SQLITE4_BIG_DBL. If a plan is found that uses the named index, 
** then the cost is calculated in the usual way.
**
** If a NOT INDEXED clause (pSrc->notIndexed!=0) was attached to the table 
** in the SELECT statement, then no indexes are considered. However, the 
** selected plan may still take advantage of the built-in rowid primary key
** index.
*/
static void bestKVIndex(
  Parse *pParse,              /* The parsing context */
  WhereClause *pWC,           /* The WHERE clause */
  SrcListItem *pSrc,  /* The FROM clause term to search */
  Bitmask notReady,           /* Mask of cursors not available for indexing */
  Bitmask notValid,           /* Cursors not available for any purpose */
  ExprList *pOrderBy,         /* The ORDER BY clause */
  ExprList *pDistinct,        /* The select-list if query is DISTINCT */
  WhereCost *pCost            /* Lowest cost query plan */
){
  int iCur = pSrc->iCursor;   /* The cursor of the table to be accessed */
  Index *pProbe;              /* An index we are evaluating */
  Index *pFirst;              /* First index to evaluate */
  Index *pPk;                 /* Primary Key index */
  int eqTermMask;             /* Current mask of valid equality operators */
  int idxEqTermMask;          /* Index mask of valid equality operators */

  /* Initialize the cost to a worst-case value */
  memset(pCost, 0, sizeof(*pCost));
  pCost->rCost = SQLITE4_BIG_DBL;
  pPk = sqlite4FindPrimaryKey(pSrc->pTab, 0);

  /* If the pSrc table is the right table of a LEFT JOIN then we may not
  ** use an index to satisfy IS NULL constraints on that table.  This is
  ** because columns might end up being NULL if the table does not match -
  ** a circumstance which the index cannot help us discover.  Ticket #2177.
  */
  if( pSrc->jointype & JT_LEFT ){
    idxEqTermMask = WO_EQ|WO_IN;
  }else{
    idxEqTermMask = WO_EQ|WO_IN|WO_ISNULL;
  }

  /* Normally, this function considers all indexes attached to the table
  ** being queried. Except, if an INDEXED BY clause is specified then only
  ** the named index is considered. And if a NOT INDEXED clause was present
  ** only the PRIMARY KEY index may be considered.  
  */
  if( pSrc->notIndexed ){
    pFirst = pPk;
  }else if( pSrc->pIndex ){
    pFirst = pSrc->pIndex;
  }else{
    pFirst = pSrc->pTab->pIndex;
  }
  eqTermMask = idxEqTermMask;

  /* Loop over all indices looking for the best one to use */
  for(pProbe=pFirst; pProbe; pProbe=pProbe->pNext){
    const tRowcnt * const aiRowEst = pProbe->aiRowEst;
    double cost;                /* Cost of using pProbe */
    double nRow;                /* Estimated number of rows in result set */
    double log10N = (double)1;  /* base-10 logarithm of nRow (inexact) */
    int rev;                    /* True to scan in reverse order */
    int wsFlags = 0;
    Bitmask used = 0;

    /* The following variables are populated based on the properties of
    ** index being evaluated. They are then used to determine the expected
    ** cost and number of rows returned.
    **
    **  nEq: 
    **    Number of equality terms that can be implemented using the index.
    **    In other words, the number of initial fields in the index that
    **    are used in == or IN or NOT NULL constraints of the WHERE clause.
    **
    **  nInMul:  
    **    The "in-multiplier". This is an estimate of how many seek operations 
    **    SQLite must perform on the index in question. For example, if the 
    **    WHERE clause is:
    **
    **      WHERE a IN (1, 2, 3) AND b IN (4, 5, 6)
    **
    **    SQLite must perform 9 lookups on an index on (a, b), so nInMul is 
    **    set to 9. Given the same schema and either of the following WHERE 
    **    clauses:
    **
    **      WHERE a =  1
    **      WHERE a >= 2
    **
    **    nInMul is set to 1.
    **
    **    If there exists a WHERE term of the form "x IN (SELECT ...)", then 
    **    the sub-select is assumed to return 25 rows for the purposes of 
    **    determining nInMul.
    **
    **  bInEst:  
    **    Set to true if there was at least one "x IN (SELECT ...)" term used 
    **    in determining the value of nInMul.  Note that the RHS of the
    **    IN operator must be a SELECT, not a value list, for this variable
    **    to be true.
    **
    **  rangeDiv:
    **    An estimate of a divisor by which to reduce the search space due
    **    to inequality constraints.  In the absence of sqlite_stat3 ANALYZE
    **    data, a single inequality reduces the search space to 1/4rd its
    **    original size (rangeDiv==4).  Two inequalities reduce the search
    **    space to 1/16th of its original size (rangeDiv==16).
    **
    **  bSort:   
    **    Boolean. True if there is an ORDER BY clause that will require an 
    **    external sort (i.e. scanning the index being evaluated will not 
    **    correctly order records).
    **
    **  bLookup: 
    **    Boolean. True if a table lookup is required for each index entry
    **    visited.  In other words, true if this is not a covering index.
    **    This is always false for the rowid primary key index of a table.
    **    For other indexes, it is true unless all the columns of the table
    **    used by the SELECT statement are present in the index (such an
    **    index is sometimes described as a covering index).
    **    For example, given the index on (a, b), the second of the following 
    **    two queries requires table b-tree lookups in order to find the value
    **    of column c, but the first does not because columns a and b are
    **    both available in the index.
    **
    **             SELECT a, b    FROM tbl WHERE a = 1;
    **             SELECT a, b, c FROM tbl WHERE a = 1;
    */
    int nEq;                      /* Number of == or IN terms matching index */
    int bInEst = 0;               /* True if "x IN (SELECT...)" seen */
    int nInMul = 1;               /* Number of distinct equalities to lookup */
    double rangeDiv = (double)1;  /* Estimated reduction in search space */
    int nBound = 0;               /* Number of range constraints seen */
    int bSort = !!pOrderBy;       /* True if external sort required */
    int bDist = !!pDistinct;      /* True if index cannot help with DISTINCT */
    int bLookup = 0;              /* True if not the PK index */
    WhereTerm *pTerm;             /* A single term of the WHERE clause */
#ifdef SQLITE4_ENABLE_STAT3
    WhereTerm *pFirstTerm = 0;    /* First term matching the index */
#endif
    int nCol = pProbe->nColumn;   /* Total columns in index record */

    if( pProbe->eIndexType==SQLITE4_INDEX_FTS5 ) continue;

    /* Unless pProbe is the primary key index, then the encoded PK column 
    ** values are at the end of each record. Set variable nCol to the total
    ** number of columns encoded into each index record, including the PK  
    ** columns.  */
    if( pProbe!=pPk ) nCol += pPk->nColumn;

    /* Determine the values of nEq and nInMul */
    for(nEq=0; nEq<nCol; nEq++){
      int iCol;                   /* Table column of nEq'th index field */
      iCol = idxColumnNumber(pProbe, pPk, nEq);
      pTerm = findTerm(pWC, iCur, iCol, notReady, eqTermMask, pProbe);
      if( pTerm==0 ) break;
      wsFlags |= WHERE_COLUMN_EQ;
      testcase( pTerm->pWC!=pWC );
      if( pTerm->eOperator & WO_IN ){
        Expr *pExpr = pTerm->pExpr;
        wsFlags |= WHERE_COLUMN_IN;
        if( ExprHasProperty(pExpr, EP_xIsSelect) ){
          /* "x IN (SELECT ...)":  Assume the SELECT returns 25 rows */
          nInMul *= 25;
          bInEst = 1;
        }else if( ALWAYS(pExpr->x.pList && pExpr->x.pList->nExpr) ){
          /* "x IN (value, value, ...)" */
          nInMul *= pExpr->x.pList->nExpr;
        }
      }else if( pTerm->eOperator & WO_ISNULL ){
        wsFlags |= WHERE_COLUMN_NULL;
      }
#ifdef SQLITE4_ENABLE_STAT3
      if( nEq==0 && pProbe->aSample ) pFirstTerm = pTerm;
#endif
      used |= pTerm->prereqRight;
    }
 
    /* If the index being considered is UNIQUE, and there is an equality 
    ** constraint for all columns in the index, then this search will find
    ** at most a single row. In this case set the WHERE_UNIQUE flag to 
    ** indicate this to the caller.
    **
    ** Otherwise, if the search may find more than one row, test to see if
    ** there is a range constraint on indexed column (nEq+1) that can be 
    ** optimized using the index. 
    */
    if( nEq>=pProbe->nColumn && pProbe->onError!=OE_None ){
      testcase( wsFlags & WHERE_COLUMN_IN );
      testcase( wsFlags & WHERE_COLUMN_NULL );
      if( (wsFlags & (WHERE_COLUMN_IN|WHERE_COLUMN_NULL))==0 ){
        wsFlags |= WHERE_UNIQUE;
      }
    }else if( (pProbe->fIndex & IDX_Unordered)==0 ){
      int j = idxColumnNumber(pProbe, pPk, nEq);
      if( findTerm(pWC, iCur, j, notReady, WO_LT|WO_LE|WO_GT|WO_GE, pProbe) ){
        WhereTerm *pTop = findTerm(pWC, iCur, j, notReady, WO_LT|WO_LE, pProbe);
        WhereTerm *pBtm = findTerm(pWC, iCur, j, notReady, WO_GT|WO_GE, pProbe);
        whereRangeScanEst(pParse, pProbe, nEq, pBtm, pTop, &rangeDiv);
        if( pTop ){
          nBound = 1;
          wsFlags |= WHERE_TOP_LIMIT;
          used |= pTop->prereqRight;
          testcase( pTop->pWC!=pWC );
        }
        if( pBtm ){
          nBound++;
          wsFlags |= WHERE_BTM_LIMIT;
          used |= pBtm->prereqRight;
          testcase( pBtm->pWC!=pWC );
        }
        wsFlags |= WHERE_COLUMN_RANGE;
      }
    }

    /* If there is an ORDER BY clause and the index being considered will
    ** naturally scan rows in the required order, set the appropriate flags
    ** in wsFlags. Otherwise, if there is an ORDER BY clause but the index
    ** will scan rows in a different order, set the bSort variable.  */
    if( isSortingIndex(
          pParse, pWC->pMaskSet, pProbe, iCur, pOrderBy, nEq, wsFlags, &rev)
    ){
      bSort = 0;
      wsFlags |= WHERE_COLUMN_RANGE|WHERE_ORDERBY;
      wsFlags |= (rev ? WHERE_REVERSE : 0);
    }

    /* If there is a DISTINCT qualifier and this index will scan rows in
    ** order of the DISTINCT expressions, clear bDist and set the appropriate
    ** flags in wsFlags. */
    if( isDistinctIndex(pParse, pWC, pProbe, iCur, pDistinct, nEq) ){
      bDist = 0;
      wsFlags |= WHERE_COLUMN_RANGE|WHERE_DISTINCT;
    }

    /* If currently calculating the cost of using an index (not the PK
    ** index), determine if all required column data may be obtained without 
    ** using the main table (i.e. if the index is a covering
    ** index for this query). If it is, set the WHERE_IDX_ONLY flag in
    ** wsFlags. Otherwise, set the bLookup variable to true.  
    **
    ** TODO: Not clear if this optimization can be applied in SQLite 4. Fix
    ** this block once that is figured out.
    */
#if 0
    if( wsFlags ){
      Bitmask m = pSrc->colUsed;
      int j;
      for(j=0; j<pProbe->nColumn; j++){
        int x = pProbe->aiColumn[j];
        if( x<BMS-1 ){
          m &= ~(((Bitmask)1)<<x);
        }
      }
      if( m==0 ){
        wsFlags |= WHERE_IDX_ONLY;
      }else{
        bLookup = 1;
      }
    }
#endif
    bLookup = (pProbe->eIndexType!=SQLITE4_INDEX_PRIMARYKEY);

    /*
    ** Estimate the number of rows of output.  For an "x IN (SELECT...)"
    ** constraint, do not let the estimate exceed half the rows in the table.
    */
    nRow = (double)(aiRowEst[nEq] * nInMul);
    if( bInEst && nRow*2>aiRowEst[0] ){
      nRow = aiRowEst[0]/2;
      nInMul = (int)(nRow / aiRowEst[nEq]);
    }

#ifdef SQLITE4_ENABLE_STAT3
    /* If the constraint is of the form x=VALUE or x IN (E1,E2,...)
    ** and we do not think that values of x are unique and if histogram
    ** data is available for column x, then it might be possible
    ** to get a better estimate on the number of rows based on
    ** VALUE and how common that value is according to the histogram.
    */
    if( nRow>(double)1 && nEq==1 && pFirstTerm!=0 && aiRowEst[1]>1 ){
      assert( (pFirstTerm->eOperator & (WO_EQ|WO_ISNULL|WO_IN))!=0 );
      if( pFirstTerm->eOperator & (WO_EQ|WO_ISNULL) ){
        testcase( pFirstTerm->eOperator==WO_EQ );
        testcase( pFirstTerm->eOperator==WO_ISNULL );
        whereEqualScanEst(pParse, pProbe, pFirstTerm->pExpr->pRight, &nRow);
      }else if( bInEst==0 ){
        assert( pFirstTerm->eOperator==WO_IN );
        whereInScanEst(pParse, pProbe, pFirstTerm->pExpr->x.pList, &nRow);
      }
    }
#endif /* SQLITE4_ENABLE_STAT3 */

    /* Adjust the number of output rows and downward to reflect rows
    ** that are excluded by range constraints.
    */
    nRow = nRow/rangeDiv;
    if( nRow<1 ) nRow = 1;

    /* Experiments run on real SQLite databases show that the time needed
    ** to do a binary search to locate a row in a table or index is roughly
    ** log10(N) times the time to move from one row to the next row within
    ** a table or index.  The actual times can vary, with the size of
    ** records being an important factor.  Both moves and searches are
    ** slower with larger records, presumably because fewer records fit
    ** on one page and hence more pages have to be fetched.
    **
    ** The ANALYZE command and the sqlite_stat1 and sqlite_stat3 tables do
    ** not give us data on the relative sizes of table and index records.
    ** So this computation assumes table records are about twice as big
    ** as index records
    */
    if( (wsFlags & WHERE_NOT_FULLSCAN)==0 ){
      /* The cost of a full table scan is a number of move operations equal
      ** to the number of rows in the table.
      **
      ** We add an additional 4x penalty to full table scans.  This causes
      ** the cost function to err on the side of choosing an index over
      ** choosing a full scan.  This 4x full-scan penalty is an arguable
      ** decision and one which we expect to revisit in the future.  But
      ** it seems to be working well enough at the moment.
      */
      cost = aiRowEst[0]*4;
    }else{
      log10N = estLog(aiRowEst[0]);
      cost = nRow;
      if( bLookup ){
        /* For an index lookup followed by a table lookup:
        **    nInMul index searches to find the start of each index range
        **  + nRow steps through the index
        **  + nRow table searches to lookup the table entry using the PK
        */
        cost += (nInMul + nRow)*log10N;
      }else{
        /* For a covering index:
        **     nInMul index searches to find the initial entry 
        **   + nRow steps through the index
        */
        cost += nInMul*log10N;
      }
    }

    /* Add in the estimated cost of sorting the result.  Actual experimental
    ** measurements of sorting performance in SQLite show that sorting time
    ** adds C*N*log10(N) to the cost, where N is the number of rows to be 
    ** sorted and C is a factor between 1.95 and 4.3.  We will split the
    ** difference and select C of 3.0.
    */
    if( bSort ){
      cost += nRow*estLog(nRow)*3;
    }
    if( bDist ){
      cost += nRow*estLog(nRow)*3;
    }

    /**** Cost of using this index has now been computed ****/

    /* If there are additional constraints on this table that cannot
    ** be used with the current index, but which might lower the number
    ** of output rows, adjust the nRow value accordingly.  This only 
    ** matters if the current index is the least costly, so do not bother
    ** with this step if we already know this index will not be chosen.
    ** Also, never reduce the output row count below 2 using this step.
    **
    ** It is critical that the notValid mask be used here instead of
    ** the notReady mask.  When computing an "optimal" index, the notReady
    ** mask will only have one bit set - the bit for the current table.
    ** The notValid mask, on the other hand, always has all bits set for
    ** tables that are not in outer loops.  If notReady is used here instead
    ** of notValid, then a optimal index that depends on inner joins loops
    ** might be selected even when there exists an optimal index that has
    ** no such dependency.
    */
    if( nRow>2 && cost<=pCost->rCost ){
      int k;                       /* Loop counter */
      int nSkipEq = nEq;           /* Number of == constraints to skip */
      int nSkipRange = nBound;     /* Number of < constraints to skip */
      Bitmask thisTab;             /* Bitmap for pSrc */

      thisTab = getMask(pWC->pMaskSet, iCur);
      for(pTerm=pWC->a, k=pWC->nTerm; nRow>2 && k; k--, pTerm++){
        if( pTerm->wtFlags & TERM_VIRTUAL ) continue;
        if( (pTerm->prereqAll & notValid)!=thisTab ) continue;
        if( pTerm->eOperator & (WO_EQ|WO_IN|WO_ISNULL) ){
          if( nSkipEq ){
            /* Ignore the first nEq equality matches since the index
            ** has already accounted for these */
            nSkipEq--;
          }else{
            /* Assume each additional equality match reduces the result
            ** set size by a factor of 10 */
            nRow /= 10;
          }
        }else if( pTerm->eOperator & (WO_LT|WO_LE|WO_GT|WO_GE) ){
          if( nSkipRange ){
            /* Ignore the first nSkipRange range constraints since the index
            ** has already accounted for these */
            nSkipRange--;
          }else{
            /* Assume each additional range constraint reduces the result
            ** set size by a factor of 3.  Indexed range constraints reduce
            ** the search space by a larger factor: 4.  We make indexed range
            ** more selective intentionally because of the subjective 
            ** observation that indexed range constraints really are more
            ** selective in practice, on average. */
            nRow /= 3;
          }
        }else if( pTerm->eOperator!=WO_NOOP ){
          /* Any other expression lowers the output row count by half */
          nRow /= 2;
        }
      }
      if( nRow<2 ) nRow = 2;
    }


    WHERETRACE((
      "%s(%s): nEq=%d nInMul=%d rangeDiv=%d bSort=%d bLookup=%d wsFlags=0x%x\n"
      "         notReady=0x%llx log10N=%.1f nRow=%.1f cost=%.1f used=0x%llx\n",
      pSrc->pTab->zName, pProbe->zName,
      nEq, nInMul, (int)rangeDiv, bSort, bLookup, wsFlags,
      notReady, log10N, nRow, cost, used
    ));

    /* If this index is the best we have seen so far, then record this
    ** index and its cost in the pCost structure.
    */
    if( (pProbe==pFirst || wsFlags || pProbe==pPk)
     && (cost<pCost->rCost || (cost<=pCost->rCost && nRow<pCost->plan.nRow))
    ){
      pCost->rCost = cost;
      pCost->used = used;
      pCost->plan.nRow = nRow;
      pCost->plan.wsFlags = wsFlags;
      pCost->plan.nEq = nEq;
      pCost->plan.u.pIdx = pProbe;
    }

    /* If there was an INDEXED BY or NOT INDEXED clause, only one index is
    ** considered. */
    if( pSrc->pIndex || pSrc->notIndexed ) break;
  }

  /* If there is no ORDER BY clause and the SQLITE4_ReverseOrder flag
  ** is set, then reverse the order that the index will be scanned
  ** in. This is used for application testing, to help find cases
  ** where application behaviour depends on the (undefined) order that
  ** SQLite outputs rows in in the absence of an ORDER BY clause.  */
  if( !pOrderBy && pParse->db->flags & SQLITE4_ReverseOrder ){
    pCost->plan.wsFlags |= WHERE_REVERSE;
  }

  assert( pOrderBy || (pCost->plan.wsFlags&WHERE_ORDERBY)==0 );
  assert( pSrc->pIndex==0 
       || pCost->plan.u.pIdx==0 
       || pCost->plan.u.pIdx==pSrc->pIndex 
  );

  WHERETRACE(("best index is: %s\n", 
    ((pCost->plan.wsFlags & WHERE_NOT_FULLSCAN)==0 ? "none" : 
         pCost->plan.u.pIdx ? pCost->plan.u.pIdx->zName : "ipk")
  ));
  
  bestOrClauseIndex(pParse, pWC, pSrc, notReady, notValid, pOrderBy, pCost);
  bestAutomaticIndex(pParse, pWC, pSrc, notReady, pCost);
  pCost->plan.wsFlags |= eqTermMask;
}

/*
** Find the query plan for accessing table pSrc->pTab. Write the
** best query plan and its cost into the WhereCost object supplied 
** as the last parameter. This function may calculate the cost of
** both real and virtual table scans.
*/
static void bestIndex(
  Parse *pParse,              /* The parsing context */
  WhereClause *pWC,           /* The WHERE clause */
  SrcListItem *pSrc,  /* The FROM clause term to search */
  Bitmask notReady,           /* Mask of cursors not available for indexing */
  Bitmask notValid,           /* Cursors not available for any purpose */
  ExprList *pOrderBy,         /* The ORDER BY clause */
  WhereCost *pCost            /* Lowest cost query plan */
){
#ifndef SQLITE4_OMIT_VIRTUALTABLE
  if( IsVirtual(pSrc->pTab) ){
    sqlite4_index_info *p = 0;
    bestVirtualIndex(pParse, pWC, pSrc, notReady, notValid, pOrderBy, pCost,&p);
    if( p->needToFreeIdxStr ){
      sqlite4_free(p->idxStr);
    }
    sqlite4DbFree(pParse->db, p);
  }else
#endif
  {
    bestKVIndex(pParse, pWC, pSrc, notReady, notValid, pOrderBy, 0, pCost);
  }
}

/*
** Disable a term in the WHERE clause.  Except, do not disable the term
** if it controls a LEFT OUTER JOIN and it did not originate in the ON
** or USING clause of that join.
**
** Consider the term t2.z='ok' in the following queries:
**







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2813
2814
2815
2816
2817
2818
2819
** for a UTF conversion required for comparison.  The error is stored
** in the pParse structure.
*/
static int whereInScanEst(
  Parse *pParse,       /* Parsing & code generating context */
  Index *p,            /* The index whose left-most column is pTerm */
  ExprList *pList,     /* The value list on the RHS of "x IN (v1,v2,v3,...)" */
  tRowcnt *pnRow       /* Write the revised row estimate here */
){
  int rc = SQLITE4_OK;     /* Subfunction return code */
  tRowcnt nEst;           /* Number of rows for a single term */
  tRowcnt nRowEst = 0;    /* New estimate of the number of rows */
  int i;                  /* Loop counter */

  assert( p->aSample!=0 );
  for(i=0; rc==SQLITE4_OK && i<pList->nExpr; i++){
    nEst = p->aiRowEst[0];
    rc = whereEqualScanEst(pParse, p, pList->a[i].pExpr, &nEst);
    nRowEst += nEst;
  }
  if( rc==SQLITE4_OK ){
    if( nRowEst > p->aiRowEst[0] ) nRowEst = p->aiRowEst[0];
    *pnRow = nRowEst;
    WHERETRACE(0x100,("IN row estimate: est=%g\n", nRowEst));
  }
  return rc;
}
#endif /* defined(SQLITE4_ENABLE_STAT3) */






















































































































































































































































































































































































































































































































































































/*
** Disable a term in the WHERE clause.  Except, do not disable the term
** if it controls a LEFT OUTER JOIN and it did not originate in the ON
** or USING clause of that join.
**
** Consider the term t2.z='ok' in the following queries:
**
3486
3487
3488
3489
3490
3491
3492
3493


3494
3495
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3500
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3525

3526








3527
3528




3529
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3557
3558

3559
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3570

3571
3572
3573
3574
3575
3576
3577
3578
3579
3580
** For a constraint of the form X=expr, the expression is evaluated and its
** result is left on the stack.  For constraints of the form X IN (...)
** this routine sets up a loop that will iterate over all values of X.
*/
static int codeEqualityTerm(
  Parse *pParse,      /* The parsing context */
  WhereTerm *pTerm,   /* The term of the WHERE clause to be coded */
  WhereLevel *pLevel, /* When level of the FROM clause we are working on */


  int iTarget         /* Attempt to leave results in this register */
){
  Expr *pX = pTerm->pExpr;
  Vdbe *v = pParse->pVdbe;
  int iReg;                  /* Register holding results */

  assert( iTarget>0 );
  if( pX->op==TK_EQ ){
    iReg = sqlite4ExprCodeTarget(pParse, pX->pRight, iTarget);
  }else if( pX->op==TK_ISNULL ){
    iReg = iTarget;
    sqlite4VdbeAddOp2(v, OP_Null, 0, iReg);
#ifndef SQLITE4_OMIT_SUBQUERY
  }else{
    /* Code a loop that iterates through the set of distinct, non-null 
    ** values in the set on the right-hand-side of the IN(...) operator.
    ** There are two ways to do this:
    **
    **   * If the SELECT statement is of the form "SELECT x FROM tbl", 
    **     and column x is subject to a UNIQUE constraint, and the 
    **     default affinity and collation sequence of column "x" match
    **     those required by the comparison, iterate through the PK
    **     index.
    **
    **   * Otherwise, materialize the set into an ephemeral index using
    **     "x" as both the key and value. Then loop through the contents
    **     of the ephemeral index.
    */
    sqlite4 *db = pParse->db;
    int iTab;
    int iCol;                     /* Column to read from cursor iTab */
    struct InLoop *pIn;










    assert( pX->op==TK_IN );
    iReg = iTarget;





    if( sqlite4FindExistingInIndex(pParse, pX, 1) ){
      /* This branch is taken if the rhs of the IN is a select of the
      ** form "SELECT x FROM tble" and column x is subject to a UNIQUE 
      ** constraint that uses the same collation sequence and affinity as
      ** this IN (...) test. In this case just loop through all values of
      ** "x", skipping any NULLs.  */
      Table *pTab = pX->x.pSelect->pSrc->a[0].pTab;
      int iDb = sqlite4SchemaToIndex(db, pTab->pSchema);
      iTab = pX->iTable = pParse->nTab++;
      sqlite4OpenPrimaryKey(pParse, iTab, iDb, pTab, OP_OpenRead);
      iCol = pX->pLeft->iColumn;
    }else{
      /* Set Parse.nQueryLoop to 1 before calling sqlite4CodeSubselect().
      ** This informs the optimizer that there is no point in constructing
      ** any automatic indexes for the outer loop of the sub-select, as it
      ** will only be run once. See also bestAutomaticIndex().  */
      int nQueryLoopSave = pParse->nQueryLoop;
      pParse->nQueryLoop = (double)1;
      sqlite4CodeSubselect(pParse, pX, 0, 0);
      pParse->nQueryLoop = nQueryLoopSave;
      iTab = pX->iTable;
      iCol = 0;
    }
    sqlite4VdbeAddOp2(v, OP_Rewind, iTab, 0);
    assert( pLevel->plan.wsFlags & WHERE_IN_ABLE );

    if( pLevel->u.in.nIn==0 ) pLevel->addrNxt = sqlite4VdbeMakeLabel(v);


    pLevel->u.in.nIn++;
    pLevel->u.in.aInLoop = sqlite4DbReallocOrFree(db, pLevel->u.in.aInLoop, 

        (sizeof(pLevel->u.in.aInLoop[0])*pLevel->u.in.nIn)
    );
    pIn = pLevel->u.in.aInLoop;

    if( pIn ){
      pIn += pLevel->u.in.nIn - 1;
      pIn->iCur = iTab;
      if( iCol>=0 ){
        pIn->addrInTop = sqlite4VdbeAddOp3(v, OP_Column, iTab, iCol, iReg);
      }else{
        pIn->addrInTop = sqlite4VdbeAddOp2(v, OP_Rowid, iTab, iReg);
      }

      sqlite4VdbeAddOp1(v, OP_IsNull, iReg);
    }else{
      assert( db->mallocFailed );
      pLevel->u.in.nIn = 0;
    }
#endif
  }
  disableTerm(pLevel, pTerm);
  return iReg;
}







|
>
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2901
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2925






2926

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2945


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2968
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2974
** For a constraint of the form X=expr, the expression is evaluated and its
** result is left on the stack.  For constraints of the form X IN (...)
** this routine sets up a loop that will iterate over all values of X.
*/
static int codeEqualityTerm(
  Parse *pParse,      /* The parsing context */
  WhereTerm *pTerm,   /* The term of the WHERE clause to be coded */
  WhereLevel *pLevel, /* The level of the FROM clause we are working on */
  int iEq,            /* Index of the equality term within this level */
  int bRev,           /* True for reverse-order IN operations */
  int iTarget         /* Attempt to leave results in this register */
){
  Expr *pX = pTerm->pExpr;
  Vdbe *v = pParse->pVdbe;
  int iReg;                  /* Register holding results */

  assert( iTarget>0 );
  if( pX->op==TK_EQ ){
    iReg = sqlite4ExprCodeTarget(pParse, pX->pRight, iTarget);
  }else if( pX->op==TK_ISNULL ){
    iReg = iTarget;
    sqlite4VdbeAddOp2(v, OP_Null, 0, iReg);
#ifndef SQLITE4_OMIT_SUBQUERY
  }else{








    int eType;






    int iTab;

    struct InLoop *pIn;
    WhereLoop *pLoop = pLevel->pWLoop;

    if( (pLoop->wsFlags & WHERE_VIRTUALTABLE)==0
      && pLoop->u.btree.pIndex!=0
      && pLoop->u.btree.pIndex->aSortOrder[iEq]
    ){
      testcase( iEq==0 );
      testcase( bRev );
      bRev = !bRev;
    }
    assert( pX->op==TK_IN );
    iReg = iTarget;
    eType = sqlite4FindInIndex(pParse, pX, 0);
    if( eType==IN_INDEX_INDEX_DESC ){
      testcase( bRev );
      bRev = !bRev;
    }




















    iTab = pX->iTable;


    sqlite4VdbeAddOp2(v, bRev ? OP_Last : OP_Rewind, iTab, 0);
    assert( (pLoop->wsFlags & WHERE_MULTI_OR)==0 );
    pLoop->wsFlags |= WHERE_IN_ABLE;
    if( pLevel->u.in.nIn==0 ){
      pLevel->addrNxt = sqlite4VdbeMakeLabel(v);
    }
    pLevel->u.in.nIn++;
    pLevel->u.in.aInLoop =
       sqlite4DbReallocOrFree(pParse->db, pLevel->u.in.aInLoop,
                              sizeof(pLevel->u.in.aInLoop[0])*pLevel->u.in.nIn);

    pIn = pLevel->u.in.aInLoop;

    if( pIn ){
      pIn += pLevel->u.in.nIn - 1;
      pIn->iCur = iTab;
      if( eType==IN_INDEX_ROWID ){
        pIn->addrInTop = sqlite4VdbeAddOp2(v, OP_Rowid, iTab, iReg);
      }else{
        pIn->addrInTop = sqlite4VdbeAddOp3(v, OP_Column, iTab, 0, iReg);
      }
      pIn->eEndLoopOp = bRev ? OP_Prev : OP_Next;
      sqlite4VdbeAddOp1(v, OP_IsNull, iReg);
    }else{

      pLevel->u.in.nIn = 0;
    }
#endif
  }
  disableTerm(pLevel, pTerm);
  return iReg;
}
3617
3618
3619
3620
3621
3622
3623
3624
3625
3626
3627
3628
3629
3630
3631
3632
3633

3634
3635
3636
3637
3638
3639

3640

3641

3642
3643
3644
3645
3646
3647
3648
3649
3650
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3660
3661
3662
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3664
3665
3666
3667
3668
3669
3670
3671
3672
3673
** no conversion should be attempted before using a t2.b value as part of
** a key to search the index. Hence the first byte in the returned affinity
** string in this example would be set to SQLITE4_AFF_NONE.
*/
static int codeAllEqualityTerms(
  Parse *pParse,        /* Parsing context */
  WhereLevel *pLevel,   /* Which nested loop of the FROM we are coding */
  WhereClause *pWC,     /* The WHERE clause */
  Bitmask notReady,     /* Which parts of FROM have not yet been coded */
  int nExtraReg,        /* Number of extra registers to allocate */
  char **pzAff          /* OUT: Set to point to affinity string */
){
  int nEq = pLevel->plan.nEq;   /* The number of == or IN constraints to code */
  Vdbe *v = pParse->pVdbe;      /* The vm under construction */
  Index *pIdx;                  /* The index being used for this loop */
  int iCur = pLevel->iTabCur;   /* The cursor of the table */
  WhereTerm *pTerm;             /* A single constraint term */

  int j;                        /* Loop counter */
  int regBase;                  /* Base register */
  int nReg;                     /* Number of registers to allocate */
  char *zAff;                   /* Affinity string to return */

  /* This module is only called on query plans that use an index. */

  assert( pLevel->plan.wsFlags & WHERE_INDEXED );

  pIdx = pLevel->plan.u.pIdx;


  /* Figure out how many memory cells we will need then allocate them.
  */
  regBase = pParse->nMem + 1;
  nReg = pLevel->plan.nEq + nExtraReg;
  pParse->nMem += nReg;

  zAff = sqlite4DbStrDup(pParse->db, sqlite4IndexAffinityStr(v, pIdx));
  if( !zAff ){
    pParse->db->mallocFailed = 1;
  }

  /* Evaluate the equality constraints
  */
  assert( pIdx->nColumn>=nEq );
  for(j=0; j<nEq; j++){
    int r1;
    int k = pIdx->aiColumn[j];
    pTerm = findTerm(pWC, iCur, k, notReady, pLevel->plan.wsFlags, pIdx);
    if( NEVER(pTerm==0) ) break;
    /* The following true for indices with redundant columns. 
    ** Ex: CREATE INDEX i1 ON t1(a,b,a); SELECT * FROM t1 WHERE a=0 AND b=0; */
    testcase( (pTerm->wtFlags & TERM_CODED)!=0 );
    testcase( pTerm->wtFlags & TERM_VIRTUAL ); /* EV: R-30575-11662 */
    r1 = codeEqualityTerm(pParse, pTerm, pLevel, regBase+j);
    if( r1!=regBase+j ){
      if( nReg==1 ){
        sqlite4ReleaseTempReg(pParse, regBase);
        regBase = r1;
      }else{
        sqlite4VdbeAddOp2(v, OP_SCopy, r1, regBase+j);
      }







|
<



|


<

>






>
|
>
|
>




|









|


<
|
|




|







3011
3012
3013
3014
3015
3016
3017
3018

3019
3020
3021
3022
3023
3024

3025
3026
3027
3028
3029
3030
3031
3032
3033
3034
3035
3036
3037
3038
3039
3040
3041
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3045
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3054

3055
3056
3057
3058
3059
3060
3061
3062
3063
3064
3065
3066
3067
3068
** no conversion should be attempted before using a t2.b value as part of
** a key to search the index. Hence the first byte in the returned affinity
** string in this example would be set to SQLITE4_AFF_NONE.
*/
static int codeAllEqualityTerms(
  Parse *pParse,        /* Parsing context */
  WhereLevel *pLevel,   /* Which nested loop of the FROM we are coding */
  int bRev,             /* Reverse the order of IN operators */

  int nExtraReg,        /* Number of extra registers to allocate */
  char **pzAff          /* OUT: Set to point to affinity string */
){
  int nEq;                      /* The number of == or IN constraints to code */
  Vdbe *v = pParse->pVdbe;      /* The vm under construction */
  Index *pIdx;                  /* The index being used for this loop */

  WhereTerm *pTerm;             /* A single constraint term */
  WhereLoop *pLoop;             /* The WhereLoop object */
  int j;                        /* Loop counter */
  int regBase;                  /* Base register */
  int nReg;                     /* Number of registers to allocate */
  char *zAff;                   /* Affinity string to return */

  /* This module is only called on query plans that use an index. */
  pLoop = pLevel->pWLoop;
  assert( (pLoop->wsFlags & WHERE_VIRTUALTABLE)==0 );
  nEq = pLoop->u.btree.nEq;
  pIdx = pLoop->u.btree.pIndex;
  assert( pIdx!=0 );

  /* Figure out how many memory cells we will need then allocate them.
  */
  regBase = pParse->nMem + 1;
  nReg = pLoop->u.btree.nEq + nExtraReg;
  pParse->nMem += nReg;

  zAff = sqlite4DbStrDup(pParse->db, sqlite4IndexAffinityStr(v, pIdx));
  if( !zAff ){
    pParse->db->mallocFailed = 1;
  }

  /* Evaluate the equality constraints
  */
  assert( idxColumnCount(pIdx, sqlite4FindPrimaryKey(pIdx->pTable, 0))>=nEq );
  for(j=0; j<nEq; j++){
    int r1;

    pTerm = pLoop->aLTerm[j];
    assert( pTerm!=0 );
    /* The following true for indices with redundant columns. 
    ** Ex: CREATE INDEX i1 ON t1(a,b,a); SELECT * FROM t1 WHERE a=0 AND b=0; */
    testcase( (pTerm->wtFlags & TERM_CODED)!=0 );
    testcase( pTerm->wtFlags & TERM_VIRTUAL ); /* EV: R-30575-11662 */
    r1 = codeEqualityTerm(pParse, pTerm, pLevel, j, bRev, regBase+j);
    if( r1!=regBase+j ){
      if( nReg==1 ){
        sqlite4ReleaseTempReg(pParse, regBase);
        regBase = r1;
      }else{
        sqlite4VdbeAddOp2(v, OP_SCopy, r1, regBase+j);
      }
3727
3728
3729
3730
3731
3732
3733
3734
3735
3736
3737
3738
3739


3740
3741
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3755
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3790


3791
3792
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3794

3795
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3801
3802
3803
3804
3805
3806
3807


3808
3809
3810
3811
3812
3813
3814
3815
3816



3817

3818


3819
3820
3821
3822



3823
3824
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3826
3827
3828
3829
3830
3831
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3833
3834
3835
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3837
3838
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3840
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3844
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3859
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3861
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3868

3869
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3874
3875

3876


3877
3878
3879
3880
3881
3882
3883
**
**   "a=? AND b>?"
**
** The returned pointer points to memory obtained from sqlite4DbMalloc().
** It is the responsibility of the caller to free the buffer when it is
** no longer required.
*/
static char *explainIndexRange(sqlite4 *db, WhereLevel *pLevel, Table *pTab){
  WherePlan *pPlan = &pLevel->plan;
  Index *pPk;
  Index *pIdx = pPlan->u.pIdx;
  int nEq = pPlan->nEq;
  int i;


  StrAccum txt;

  pPk = sqlite4FindPrimaryKey(pTab, 0);
  if( nEq==0 && (pPlan->wsFlags & (WHERE_BTM_LIMIT|WHERE_TOP_LIMIT))==0 ){
    return 0;
  }
  sqlite4StrAccumInit(&txt, 0, 0, SQLITE4_MAX_LENGTH);
  txt.db = db;
  txt.pEnv = db->pEnv;

  sqlite4StrAccumAppend(&txt, " (", 2);
  for(i=0; i<nEq; i++){
    const char *zCol = tblColumnName(pTab, idxColumnNumber(pIdx, pPk, i));
    explainAppendTerm(&txt, i, zCol, "=");
  }


  if( pPlan->wsFlags&WHERE_BTM_LIMIT ){
    const char *zCol = tblColumnName(pTab, idxColumnNumber(pIdx, pPk, nEq));
    explainAppendTerm(&txt, i++, zCol, ">");
  }
  if( pPlan->wsFlags&WHERE_TOP_LIMIT ){
    const char *zCol = tblColumnName(pTab, idxColumnNumber(pIdx, pPk, nEq));
    explainAppendTerm(&txt, i, zCol, "<");
  }
  sqlite4StrAccumAppend(&txt, ")", 1);
  return sqlite4StrAccumFinish(&txt);
}

/*
** This function is a no-op unless currently processing an EXPLAIN QUERY PLAN
** command. If the query being compiled is an EXPLAIN QUERY PLAN, a single
** record is added to the output to describe the table scan strategy in 
** pLevel.
*/
static void explainOneScan(
  Parse *pParse,                  /* Parse context */
  SrcList *pTabList,              /* Table list this loop refers to */
  WhereLevel *pLevel,             /* Scan to write OP_Explain opcode for */
  int iLevel,                     /* Value for "level" column of output */
  int iFrom,                      /* Value for "from" column of output */
  u16 wctrlFlags                  /* Flags passed to sqlite4WhereBegin() */
){
  if( pParse->explain==2 ){
    u32 flags = pLevel->plan.wsFlags;
    SrcListItem *pItem = &pTabList->a[pLevel->iFrom];
    Vdbe *v = pParse->pVdbe;      /* VM being constructed */
    sqlite4 *db = pParse->db;     /* Database handle */
    char *zMsg;                   /* Text to add to EQP output */
    sqlite4_int64 nRow;           /* Expected number of rows visited by scan */
    int iId = pParse->iSelectId;  /* Select id (left-most output column) */
    int isSearch;                 /* True for a SEARCH. False for SCAN. */





    if( (flags&WHERE_MULTI_OR) || (wctrlFlags&WHERE_ONETABLE_ONLY) ) return;

    isSearch = (pLevel->plan.nEq>0)
             || (flags&(WHERE_BTM_LIMIT|WHERE_TOP_LIMIT))!=0

             || (wctrlFlags&(WHERE_ORDERBY_MIN|WHERE_ORDERBY_MAX));

    zMsg = sqlite4MPrintf(db, "%s", isSearch?"SEARCH":"SCAN");
    if( pItem->pSelect ){
      zMsg = sqlite4MAppendf(db, zMsg, "%s SUBQUERY %d", zMsg,pItem->iSelectId);
    }else{
      zMsg = sqlite4MAppendf(db, zMsg, "%s TABLE %s", zMsg, pItem->zName);
    }

    if( pItem->zAlias ){
      zMsg = sqlite4MAppendf(db, zMsg, "%s AS %s", zMsg, pItem->zAlias);
    }
    if( (flags & WHERE_INDEXED)!=0 ){


      char *zWhere = explainIndexRange(db, pLevel, pItem->pTab);
      Index *pIdx = pLevel->plan.u.pIdx;
      const char *zName = "";
      const char *zType = "INDEX";

      if( pIdx->eIndexType==SQLITE4_INDEX_PRIMARYKEY ){
        zType = "PRIMARY KEY";
      }else if( 0==(flags & WHERE_TEMP_INDEX) ){
        zName = pIdx->zName;



      }

      zMsg = sqlite4MAppendf(db, zMsg, "%s USING %s%s%s%s%s", zMsg, 


          ((flags & WHERE_TEMP_INDEX)?"AUTOMATIC ":""),
          zType, (zName[0] ? " " : ""), zName, zWhere
      );
      sqlite4DbFree(db, zWhere);



    }
#ifndef SQLITE4_OMIT_VIRTUALTABLE
    else if( (flags & WHERE_VIRTUALTABLE)!=0 ){
      sqlite4_index_info *pVtabIdx = pLevel->plan.u.pVtabIdx;
      zMsg = sqlite4MAppendf(db, zMsg, "%s VIRTUAL TABLE INDEX %d:%s", zMsg,
                  pVtabIdx->idxNum, pVtabIdx->idxStr);
    }
#endif
    if( wctrlFlags&(WHERE_ORDERBY_MIN|WHERE_ORDERBY_MAX) ){
      testcase( wctrlFlags & WHERE_ORDERBY_MIN );
      nRow = 1;
    }else{
      nRow = (sqlite4_int64)pLevel->plan.nRow;
    }
    zMsg = sqlite4MAppendf(db, zMsg, "%s (~%lld rows)", zMsg, nRow);
    sqlite4VdbeAddOp4(v, OP_Explain, iId, iLevel, iFrom, zMsg, P4_DYNAMIC);
  }
}
#else
# define explainOneScan(u,v,w,x,y,z)
#endif /* SQLITE4_OMIT_EXPLAIN */


/*
** Generate code for the start of the iLevel-th loop in the WHERE clause
** implementation described by pWInfo.
*/
static Bitmask codeOneLoopStart(
  WhereInfo *pWInfo,   /* Complete information about the WHERE clause */
  int iLevel,          /* Which level of pWInfo->a[] should be coded */
  u16 wctrlFlags,      /* One of the WHERE_* flags defined in sqliteInt.h */
  Bitmask notReady,    /* Which tables are currently available */
  Expr *pWhere         /* Complete WHERE clause */
){
  int j, k;            /* Loop counters */
  int iCur;            /* The VDBE cursor for the table */
  int addrNxt;         /* Where to jump to continue with the next IN case */

  int bRev;            /* True if we need to scan in reverse order */
  WhereLevel *pLevel;  /* The where level to be coded */

  WhereClause *pWC;    /* Decomposition of the entire WHERE clause */
  WhereTerm *pTerm;               /* A WHERE clause term */
  Parse *pParse;                  /* Parsing context */
  Vdbe *v;                        /* The prepared stmt under constructions */
  SrcListItem *pTabItem;  /* FROM clause term being coded */
  int addrBrk;                    /* Jump here to break out of the loop */
  int addrCont;                   /* Jump here to continue with next cycle */

  int iReleaseReg = 0;            /* Temp register to free before returning */


  pParse = pWInfo->pParse;
  v = pParse->pVdbe;
  pWC = pWInfo->pWC;
  pLevel = &pWInfo->a[iLevel];

  pTabItem = &pWInfo->pTabList->a[pLevel->iFrom];
  iCur = pTabItem->iCursor;

  bRev = (pLevel->plan.wsFlags & WHERE_REVERSE)!=0;



  /* Create labels for the "break" and "continue" instructions
  ** for the current loop.  Jump to addrBrk to break out of a loop.
  ** Jump to cont to go immediately to the next iteration of the
  ** loop.
  **
  ** When there is an IN operator, we also have a "addrNxt" label that







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**
**   "a=? AND b>?"
**
** The returned pointer points to memory obtained from sqlite4DbMalloc().
** It is the responsibility of the caller to free the buffer when it is
** no longer required.
*/
static char *explainIndexRange(sqlite4 *db, WhereLoop *pLoop, Table *pTab){

  Index *pIndex = pLoop->u.btree.pIndex;

  int nEq = pLoop->u.btree.nEq;
  int i, j;
  Column *aCol = pTab->aCol;
  int *aiColumn = pIndex->aiColumn;
  StrAccum txt;


  if( nEq==0 && (pLoop->wsFlags & (WHERE_BTM_LIMIT|WHERE_TOP_LIMIT))==0 ){
    return 0;
  }
  sqlite4StrAccumInit(&txt, 0, 0, SQLITE4_MAX_LENGTH);
  txt.db = db;


  sqlite4StrAccumAppend(&txt, " (", 2);
  for(i=0; i<nEq; i++){

    explainAppendTerm(&txt, i, aCol[aiColumn[i]].zName, "=");
  }

  j = i;
  if( pLoop->wsFlags&WHERE_BTM_LIMIT ){
    char *z = (j==pIndex->nColumn ) ? "rowid" : aCol[aiColumn[j]].zName;
    explainAppendTerm(&txt, i++, z, ">");
  }
  if( pLoop->wsFlags&WHERE_TOP_LIMIT ){
    char *z = (j==pIndex->nColumn ) ? "rowid" : aCol[aiColumn[j]].zName;
    explainAppendTerm(&txt, i, z, "<");
  }
  sqlite4StrAccumAppend(&txt, ")", 1);
  return sqlite4StrAccumFinish(&txt);
}

/*
** This function is a no-op unless currently processing an EXPLAIN QUERY PLAN
** command. If the query being compiled is an EXPLAIN QUERY PLAN, a single
** record is added to the output to describe the table scan strategy in 
** pLevel.
*/
static void explainOneScan(
  Parse *pParse,                  /* Parse context */
  SrcList *pTabList,              /* Table list this loop refers to */
  WhereLevel *pLevel,             /* Scan to write OP_Explain opcode for */
  int iLevel,                     /* Value for "level" column of output */
  int iFrom,                      /* Value for "from" column of output */
  u16 wctrlFlags                  /* Flags passed to sqlite4WhereBegin() */
){
  if( pParse->explain==2 ){

    struct SrcListItem *pItem = &pTabList->a[pLevel->iFrom];
    Vdbe *v = pParse->pVdbe;      /* VM being constructed */
    sqlite4 *db = pParse->db;     /* Database handle */
    char *zMsg;                   /* Text to add to EQP output */

    int iId = pParse->iSelectId;  /* Select id (left-most output column) */
    int isSearch;                 /* True for a SEARCH. False for SCAN. */
    WhereLoop *pLoop;             /* The controlling WhereLoop object */
    u32 flags;                    /* Flags that describe this loop */

    pLoop = pLevel->pWLoop;
    flags = pLoop->wsFlags;
    if( (flags&WHERE_MULTI_OR) || (wctrlFlags&WHERE_ONETABLE_ONLY) ) return;


    isSearch = (flags&(WHERE_BTM_LIMIT|WHERE_TOP_LIMIT))!=0
            || ((flags&WHERE_VIRTUALTABLE)==0 && (pLoop->u.btree.nEq>0))
            || (wctrlFlags&(WHERE_ORDERBY_MIN|WHERE_ORDERBY_MAX));

    zMsg = sqlite4MPrintf(db, "%s", isSearch?"SEARCH":"SCAN");
    if( pItem->pSelect ){
      zMsg = sqlite4MAppendf(db, zMsg, "%s SUBQUERY %d", zMsg,pItem->iSelectId);
    }else{
      zMsg = sqlite4MAppendf(db, zMsg, "%s TABLE %s", zMsg, pItem->zName);
    }

    if( pItem->zAlias ){
      zMsg = sqlite4MAppendf(db, zMsg, "%s AS %s", zMsg, pItem->zAlias);
    }
    if( (flags & (WHERE_IPK|WHERE_VIRTUALTABLE))==0
     && ALWAYS(pLoop->u.btree.pIndex!=0)
    ){
      char *zWhere = explainIndexRange(db, pLoop, pItem->pTab);

      zMsg = sqlite4MAppendf(db, zMsg,
               ((flags & WHERE_AUTO_INDEX) ? 
                   "%s USING AUTOMATIC %sINDEX%.0s%s" :
                   "%s USING %sINDEX %s%s"), 

               zMsg, ((flags & WHERE_IDX_ONLY) ? "COVERING " : ""),
               pLoop->u.btree.pIndex->zName, zWhere);
      sqlite4DbFree(db, zWhere);
    }else if( (flags & WHERE_IPK)!=0 && (flags & WHERE_CONSTRAINT)!=0 ){
      zMsg = sqlite4MAppendf(db, zMsg, "%s USING INTEGER PRIMARY KEY", zMsg);

      if( flags&(WHERE_COLUMN_EQ|WHERE_COLUMN_IN) ){
        zMsg = sqlite4MAppendf(db, zMsg, "%s (rowid=?)", zMsg);
      }else if( (flags&WHERE_BOTH_LIMIT)==WHERE_BOTH_LIMIT ){
        zMsg = sqlite4MAppendf(db, zMsg, "%s (rowid>? AND rowid<?)", zMsg);
      }else if( flags&WHERE_BTM_LIMIT ){


        zMsg = sqlite4MAppendf(db, zMsg, "%s (rowid>?)", zMsg);
      }else if( ALWAYS(flags&WHERE_TOP_LIMIT) ){
        zMsg = sqlite4MAppendf(db, zMsg, "%s (rowid<?)", zMsg);
      }
    }
#ifndef SQLITE4_OMIT_VIRTUALTABLE
    else if( (flags & WHERE_VIRTUALTABLE)!=0 ){

      zMsg = sqlite4MAppendf(db, zMsg, "%s VIRTUAL TABLE INDEX %d:%s", zMsg,
                  pLoop->u.vtab.idxNum, pLoop->u.vtab.idxStr);
    }
#endif






    zMsg = sqlite4MAppendf(db, zMsg, "%s", zMsg);
    sqlite4VdbeAddOp4(v, OP_Explain, iId, iLevel, iFrom, zMsg, P4_DYNAMIC);
  }
}
#else
# define explainOneScan(u,v,w,x,y,z)
#endif /* SQLITE4_OMIT_EXPLAIN */


/*
** Generate code for the start of the iLevel-th loop in the WHERE clause
** implementation described by pWInfo.
*/
static Bitmask codeOneLoopStart(
  WhereInfo *pWInfo,   /* Complete information about the WHERE clause */
  int iLevel,          /* Which level of pWInfo->a[] should be coded */

  Bitmask notReady     /* Which tables are currently available */

){
  int j, k;            /* Loop counters */
  int iCur;            /* The VDBE cursor for the table */
  int addrNxt;         /* Where to jump to continue with the next IN case */
  int omitTable;       /* True if we use the index only */
  int bRev;            /* True if we need to scan in reverse order */
  WhereLevel *pLevel;  /* The where level to be coded */
  WhereLoop *pLoop;    /* The WhereLoop object being coded */
  WhereClause *pWC;    /* Decomposition of the entire WHERE clause */
  WhereTerm *pTerm;               /* A WHERE clause term */
  Parse *pParse;                  /* Parsing context */
  Vdbe *v;                        /* The prepared stmt under constructions */
  struct SrcListItem *pTabItem;  /* FROM clause term being coded */
  int addrBrk;                    /* Jump here to break out of the loop */
  int addrCont;                   /* Jump here to continue with next cycle */
  int iRowidReg = 0;        /* Rowid is stored in this register, if not zero */
  int iReleaseReg = 0;      /* Temp register to free before returning */
  Bitmask newNotReady;      /* Return value */

  pParse = pWInfo->pParse;
  v = pParse->pVdbe;
  pWC = &pWInfo->sWC;
  pLevel = &pWInfo->a[iLevel];
  pLoop = pLevel->pWLoop;
  pTabItem = &pWInfo->pTabList->a[pLevel->iFrom];
  iCur = pTabItem->iCursor;
  bRev = (pWInfo->revMask>>iLevel)&1;
  omitTable = (pLoop->wsFlags & WHERE_IDX_ONLY)!=0 
           && (pWInfo->wctrlFlags & WHERE_FORCE_TABLE)==0;
  VdbeNoopComment((v, "Begin Join Loop %d", iLevel));

  /* Create labels for the "break" and "continue" instructions
  ** for the current loop.  Jump to addrBrk to break out of a loop.
  ** Jump to cont to go immediately to the next iteration of the
  ** loop.
  **
  ** When there is an IN operator, we also have a "addrNxt" label that
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  */
  if( pLevel->iFrom>0 && (pTabItem[0].jointype & JT_LEFT)!=0 ){
    pLevel->iLeftJoin = ++pParse->nMem;
    sqlite4VdbeAddOp2(v, OP_Integer, 0, pLevel->iLeftJoin);
    VdbeComment((v, "init LEFT JOIN no-match flag"));
  }

  if( (pLevel->plan.wsFlags & WHERE_INDEXED)
   && (pLevel->plan.u.pIdx->eIndexType==SQLITE4_INDEX_FTS5)
  ){
    /* Case -1:  An FTS query */
    int iTerm;
    int rMatch;
    int rFree;
    findMatchExpr(pParse, pWC, pTabItem, &iTerm);

    rMatch = sqlite4ExprCodeTemp(pParse, pWC->a[iTerm].pExpr->pRight, &rFree);
    pWC->a[iTerm].wtFlags |= TERM_CODED;
    sqlite4Fts5CodeQuery(pParse, 
        pLevel->plan.u.pIdx, pLevel->iIdxCur, addrBrk, rMatch
    );
    sqlite4ReleaseTempReg(pParse, rFree);

    pLevel->p2 = sqlite4VdbeCurrentAddr(v);
    sqlite4VdbeAddOp3(v, OP_SeekPk, iCur, 0, pLevel->iIdxCur);
    pLevel->op = OP_FtsNext;
    pLevel->p1 = pLevel->iIdxCur;
  }else 


#ifndef SQLITE4_OMIT_VIRTUALTABLE
  if(  (pLevel->plan.wsFlags & WHERE_VIRTUALTABLE)!=0 ){
    /* Case 0:  The table is a virtual-table.  Use the VFilter and VNext
    **          to access the data.
    */
    int iReg;   /* P3 Value for OP_VFilter */
    sqlite4_index_info *pVtabIdx = pLevel->plan.u.pVtabIdx;
    int nConstraint = pVtabIdx->nConstraint;
    struct sqlite4_index_constraint_usage *aUsage =
                                                pVtabIdx->aConstraintUsage;
    const struct sqlite4_index_constraint *aConstraint =
                                                pVtabIdx->aConstraint;

    sqlite4ExprCachePush(pParse);
    iReg = sqlite4GetTempRange(pParse, nConstraint+2);

    for(j=1; j<=nConstraint; j++){
      for(k=0; k<nConstraint; k++){

        if( aUsage[k].argvIndex==j ){
          int iTerm = aConstraint[k].iTermOffset;
          sqlite4ExprCode(pParse, pWC->a[iTerm].pExpr->pRight, iReg+j+1);
          break;

        }

      }
      if( k==nConstraint ) break;
    }
    sqlite4VdbeAddOp2(v, OP_Integer, pVtabIdx->idxNum, iReg);
    sqlite4VdbeAddOp2(v, OP_Integer, j-1, iReg+1);
    sqlite4VdbeAddOp4(v, OP_VFilter, iCur, addrBrk, iReg, pVtabIdx->idxStr,

                      pVtabIdx->needToFreeIdxStr ? P4_MPRINTF : P4_STATIC);
    pVtabIdx->needToFreeIdxStr = 0;
    for(j=0; j<nConstraint; j++){
      if( aUsage[j].omit ){
        int iTerm = aConstraint[j].iTermOffset;
        disableTerm(pLevel, &pWC->a[iTerm]);
      }
    }
    pLevel->op = OP_VNext;
    pLevel->p1 = iCur;
    pLevel->p2 = sqlite4VdbeCurrentAddr(v);
    sqlite4ReleaseTempRange(pParse, iReg, nConstraint+2);
    sqlite4ExprCachePop(pParse, 1);
  }else
#endif /* SQLITE4_OMIT_VIRTUALTABLE */


  if( pLevel->plan.wsFlags & (WHERE_COLUMN_RANGE|WHERE_COLUMN_EQ) ){










































































































    /* Case 3: A scan using an index.
    **
    **         The WHERE clause may contain zero or more equality 
    **         terms ("==" or "IN" operators) that refer to the N
    **         left-most columns of the index. It may also contain
    **         inequality constraints (>, <, >= or <=) on the indexed
    **         column that immediately follows the N equalities. Only 
    **         the right-most column can be an inequality - the rest must







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  */
  if( pLevel->iFrom>0 && (pTabItem[0].jointype & JT_LEFT)!=0 ){
    pLevel->iLeftJoin = ++pParse->nMem;
    sqlite4VdbeAddOp2(v, OP_Integer, 0, pLevel->iLeftJoin);
    VdbeComment((v, "init LEFT JOIN no-match flag"));
  }

#if 0


  /* Special case of a FROM clause subquery implemented as a co-routine */



  if( pTabItem->viaCoroutine ){
    int regYield = pTabItem->regReturn;


    sqlite4VdbeAddOp2(v, OP_Integer, pTabItem->addrFillSub-1, regYield);
    pLevel->p2 =  sqlite4VdbeAddOp1(v, OP_Yield, regYield);


    VdbeComment((v, "next row of co-routine %s", pTabItem->pTab->zName));

    sqlite4VdbeAddOp2(v, OP_If, regYield+1, addrBrk);
    pLevel->op = OP_Goto;

  }else
#endif

#ifndef SQLITE4_OMIT_VIRTUALTABLE
  if(  (pLoop->wsFlags & WHERE_VIRTUALTABLE)!=0 ){
    /* Case 1:  The table is a virtual-table.  Use the VFilter and VNext
    **          to access the data.
    */
    int iReg;   /* P3 Value for OP_VFilter */
    int addrNotFound;
    int nConstraint = pLoop->nLTerm;





    sqlite4ExprCachePush(pParse);
    iReg = sqlite4GetTempRange(pParse, nConstraint+2);
    addrNotFound = pLevel->addrBrk;
    for(j=0; j<nConstraint; j++){
      int iTarget = iReg+j+2;
      pTerm = pLoop->aLTerm[j];
      if( pTerm==0 ) continue;
      if( pTerm->eOperator & WO_IN ){
        codeEqualityTerm(pParse, pTerm, pLevel, j, bRev, iTarget);

        addrNotFound = pLevel->addrNxt;
      }else{
        sqlite4ExprCode(pParse, pTerm->pExpr->pRight, iTarget);
      }

    }
    sqlite4VdbeAddOp2(v, OP_Integer, pLoop->u.vtab.idxNum, iReg);
    sqlite4VdbeAddOp2(v, OP_Integer, nConstraint, iReg+1);
    sqlite4VdbeAddOp4(v, OP_VFilter, iCur, addrNotFound, iReg,
                      pLoop->u.vtab.idxStr,
                      pLoop->u.vtab.needFree ? P4_MPRINTF : P4_STATIC);
    pLoop->u.vtab.needFree = 0;
    for(j=0; j<nConstraint && j<16; j++){
      if( (pLoop->u.vtab.omitMask>>j)&1 ){

        disableTerm(pLevel, pLoop->aLTerm[j]);
      }
    }
    pLevel->op = OP_VNext;
    pLevel->p1 = iCur;
    pLevel->p2 = sqlite4VdbeCurrentAddr(v);
    sqlite4ReleaseTempRange(pParse, iReg, nConstraint+2);
    sqlite4ExprCachePop(pParse, 1);
  }else
#endif /* SQLITE4_OMIT_VIRTUALTABLE */

  if( (pLoop->wsFlags & WHERE_IPK)!=0
   && (pLoop->wsFlags & (WHERE_COLUMN_IN|WHERE_COLUMN_EQ))!=0
  ){
    assert( 0 );

    /* Case 2:  We can directly reference a single row using an
    **          equality comparison against the ROWID field.  Or
    **          we reference multiple rows using a "rowid IN (...)"
    **          construct.
    */
    assert( pLoop->u.btree.nEq==1 );
    iReleaseReg = sqlite4GetTempReg(pParse);
    pTerm = pLoop->aLTerm[0];
    assert( pTerm!=0 );
    assert( pTerm->pExpr!=0 );
    assert( omitTable==0 );
    testcase( pTerm->wtFlags & TERM_VIRTUAL ); /* EV: R-30575-11662 */
    iRowidReg = codeEqualityTerm(pParse, pTerm, pLevel, 0, bRev, iReleaseReg);
    addrNxt = pLevel->addrNxt;
    sqlite4VdbeAddOp2(v, OP_MustBeInt, iRowidReg, addrNxt);
    sqlite4VdbeAddOp3(v, OP_NotExists, iCur, addrNxt, iRowidReg);
    sqlite4ExprCacheAffinityChange(pParse, iRowidReg, 1);
    sqlite4ExprCacheStore(pParse, iCur, -1, iRowidReg);
    VdbeComment((v, "pk"));
    pLevel->op = OP_Noop;
  }else if( (pLoop->wsFlags & WHERE_IPK)!=0
         && (pLoop->wsFlags & WHERE_COLUMN_RANGE)!=0
  ){
    /* Case 3:  We have an inequality comparison against the ROWID field.
    */
    int testOp = OP_Noop;
    int start;
    int memEndValue = 0;
    WhereTerm *pStart, *pEnd;

    assert( 0 );

    assert( omitTable==0 );
    j = 0;
    pStart = pEnd = 0;
    if( pLoop->wsFlags & WHERE_BTM_LIMIT ) pStart = pLoop->aLTerm[j++];
    if( pLoop->wsFlags & WHERE_TOP_LIMIT ) pEnd = pLoop->aLTerm[j++];
    assert( pStart!=0 || pEnd!=0 );
    if( bRev ){
      pTerm = pStart;
      pStart = pEnd;
      pEnd = pTerm;
    }
    if( pStart ){
      Expr *pX;             /* The expression that defines the start bound */
      int r1, rTemp;        /* Registers for holding the start boundary */

      /* The following constant maps TK_xx codes into corresponding 
      ** seek opcodes.  It depends on a particular ordering of TK_xx
      */
      const u8 aMoveOp[] = {
           /* TK_GT */  OP_SeekGt,
           /* TK_LE */  OP_SeekLe,
           /* TK_LT */  OP_SeekLt,
           /* TK_GE */  OP_SeekGe
      };
      assert( TK_LE==TK_GT+1 );      /* Make sure the ordering.. */
      assert( TK_LT==TK_GT+2 );      /*  ... of the TK_xx values... */
      assert( TK_GE==TK_GT+3 );      /*  ... is correcct. */

      assert( (pStart->wtFlags & TERM_VNULL)==0 );
      testcase( pStart->wtFlags & TERM_VIRTUAL ); /* EV: R-30575-11662 */
      pX = pStart->pExpr;
      assert( pX!=0 );
      testcase( pStart->leftCursor!=iCur ); /* transitive constraints */
      r1 = sqlite4ExprCodeTemp(pParse, pX->pRight, &rTemp);
      sqlite4VdbeAddOp3(v, aMoveOp[pX->op-TK_GT], iCur, addrBrk, r1);
      VdbeComment((v, "pk"));
      sqlite4ExprCacheAffinityChange(pParse, r1, 1);
      sqlite4ReleaseTempReg(pParse, rTemp);
      disableTerm(pLevel, pStart);
    }else{
      sqlite4VdbeAddOp2(v, bRev ? OP_Last : OP_Rewind, iCur, addrBrk);
    }
    if( pEnd ){
      Expr *pX;
      pX = pEnd->pExpr;
      assert( pX!=0 );
      assert( (pEnd->wtFlags & TERM_VNULL)==0 );
      testcase( pEnd->leftCursor!=iCur ); /* Transitive constraints */
      testcase( pEnd->wtFlags & TERM_VIRTUAL ); /* EV: R-30575-11662 */
      memEndValue = ++pParse->nMem;
      sqlite4ExprCode(pParse, pX->pRight, memEndValue);
      if( pX->op==TK_LT || pX->op==TK_GT ){
        testOp = bRev ? OP_Le : OP_Ge;
      }else{
        testOp = bRev ? OP_Lt : OP_Gt;
      }
      disableTerm(pLevel, pEnd);
    }
    start = sqlite4VdbeCurrentAddr(v);
    pLevel->op = bRev ? OP_Prev : OP_Next;
    pLevel->p1 = iCur;
    pLevel->p2 = start;
    assert( pLevel->p5==0 );
    if( testOp!=OP_Noop ){
      iRowidReg = iReleaseReg = sqlite4GetTempReg(pParse);
      sqlite4VdbeAddOp2(v, OP_Rowid, iCur, iRowidReg);
      sqlite4ExprCacheStore(pParse, iCur, -1, iRowidReg);
      sqlite4VdbeAddOp3(v, testOp, memEndValue, addrBrk, iRowidReg);
      sqlite4VdbeChangeP5(v, SQLITE4_AFF_NUMERIC | SQLITE4_JUMPIFNULL);
    }
  }else if( pLoop->wsFlags & WHERE_INDEXED ){
    /* Case 4: A scan using an index.
    **
    **         The WHERE clause may contain zero or more equality 
    **         terms ("==" or "IN" operators) that refer to the N
    **         left-most columns of the index. It may also contain
    **         inequality constraints (>, <, >= or <=) on the indexed
    **         column that immediately follows the N equalities. Only 
    **         the right-most column can be an inequality - the rest must
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      OP_Noop,             /* 0: (!end_constraints) */
      OP_IdxGE,            /* 1: (end_constraints && !endEq && !bRev) */
      OP_IdxLE,            /* 2: (end_constraints && !endEq &&  bRev) */
      OP_IdxGT,            /* 3: (end_constraints &&  endEq && !bRev) */
      OP_IdxLT             /* 4: (end_constraints &&  endEq &&  bRev) */
    };

    int nEq = pLevel->plan.nEq;  /* Number of == or IN terms */
    int isMinQuery = 0;          /* If this is an optimized SELECT min(x).. */
    int regBase;                 /* Base register holding constraint values */
    int r1;                      /* Temp register */
    WhereTerm *pRangeStart = 0;  /* Inequality constraint at range start */
    WhereTerm *pRangeEnd = 0;    /* Inequality constraint at range end */
    int startEq;                 /* True if range start uses ==, >= or <= */
    int endEq;                   /* True if range end uses ==, >= or <= */
    int start_constraints;       /* Start of range is constrained */
    int nConstraint;             /* Number of constraint terms */
    Index *pIdx;                 /* The index we will be using */
    int iIdxCur;                 /* The VDBE cursor for the index */
    int nExtraReg = 0;           /* Number of extra registers needed */
    int op;                      /* Instruction opcode */
    char *zStartAff;             /* Affinity for start of range constraint */
    char *zEndAff;               /* Affinity for end of range constraint */
    int regEndKey;               /* Register for end-key */
    int iIneq;                   /* The table column subject to inequality */
    Index *pPk;                  /* Primary key index on same table as pIdx */

    pIdx = pLevel->plan.u.pIdx;
    pPk = sqlite4FindPrimaryKey(pIdx->pTable, 0);
    iIneq = idxColumnNumber(pIdx, pPk, nEq);
    iIdxCur = pLevel->iIdxCur;
    assert( iCur==pLevel->iTabCur );

    /* If this loop satisfies a sort order (pOrderBy) request that 
    ** was passed to this function to implement a "SELECT min(x) ..." 
    ** query, then the caller will only allow the loop to run for
    ** a single iteration. This means that the first row returned
    ** should not have a NULL value stored in 'x'. If column 'x' is
    ** the first one after the nEq equality constraints in the index,
    ** this requires some special handling.
    */
    if( (wctrlFlags&WHERE_ORDERBY_MIN)!=0
     && (pLevel->plan.wsFlags&WHERE_ORDERBY)
     && (pIdx->nColumn>nEq)
    ){
      /* assert( pOrderBy->nExpr==1 ); */
      /* assert( pOrderBy->a[0].pExpr->iColumn==pIdx->aiColumn[nEq] ); */
      isMinQuery = 1;
      nExtraReg = 1;
    }

    /* Find any inequality constraint terms for the start and end 
    ** of the range.  */


    if( pLevel->plan.wsFlags & WHERE_TOP_LIMIT ){
      pRangeEnd = findTerm(pWC, iCur, iIneq, notReady, (WO_LT|WO_LE), pIdx);
      nExtraReg = 1;
    }
    if( pLevel->plan.wsFlags & WHERE_BTM_LIMIT ){
      pRangeStart = findTerm(pWC, iCur, iIneq, notReady, (WO_GT|WO_GE), pIdx);
      nExtraReg = 1;
    }

    /* Generate code to evaluate all constraint terms using == or IN
    ** and store the values of those terms in an array of registers
    ** starting at regBase. Ensure that nExtraReg registers are allocated
    ** immediately following the array.
    */
    regBase = codeAllEqualityTerms(
        pParse, pLevel, pWC, notReady, nExtraReg, &zStartAff
    );
    assert( (regBase+nEq+nExtraReg-1)<=pParse->nMem );

    zEndAff = sqlite4DbStrDup(pParse->db, zStartAff);
    addrNxt = pLevel->addrNxt;

    /* If we are doing a reverse order scan on an ascending index, or
    ** a forward order scan on a descending index, interchange the 
    ** start and end terms (pRangeStart and pRangeEnd).  */

    if( (nEq<pIdx->nColumn && bRev==(pIdx->aSortOrder[nEq]==SQLITE4_SO_ASC))
     || (bRev && pIdx->nColumn==nEq)
    ){
      SWAP(WhereTerm *, pRangeEnd, pRangeStart);
    }

    testcase( pRangeStart && pRangeStart->eOperator & WO_LE );
    testcase( pRangeStart && pRangeStart->eOperator & WO_GE );
    testcase( pRangeEnd && pRangeEnd->eOperator & WO_LE );
    testcase( pRangeEnd && pRangeEnd->eOperator & WO_GE );
    startEq = !pRangeStart || pRangeStart->eOperator & (WO_LE|WO_GE);
    endEq =   !pRangeEnd || pRangeEnd->eOperator & (WO_LE|WO_GE);
    start_constraints = pRangeStart || nEq>0;

    /* Seek the index cursor to the start of the range. */
    nConstraint = nEq;
    if( pRangeStart ){







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      OP_Noop,             /* 0: (!end_constraints) */
      OP_IdxGE,            /* 1: (end_constraints && !endEq && !bRev) */
      OP_IdxLE,            /* 2: (end_constraints && !endEq &&  bRev) */
      OP_IdxGT,            /* 3: (end_constraints &&  endEq && !bRev) */
      OP_IdxLT             /* 4: (end_constraints &&  endEq &&  bRev) */
    };

    int nEq = pLoop->u.btree.nEq;  /* Number of == or IN terms */
    int isMinQuery = 0;            /* If this is an optimized SELECT min(x).. */
    int regBase;                 /* Base register holding constraint values */
    int r1;                      /* Temp register */
    WhereTerm *pRangeStart = 0;  /* Inequality constraint at range start */
    WhereTerm *pRangeEnd = 0;    /* Inequality constraint at range end */
    int startEq;                 /* True if range start uses ==, >= or <= */
    int endEq;                   /* True if range end uses ==, >= or <= */
    int start_constraints;       /* Start of range is constrained */
    int nConstraint;             /* Number of constraint terms */
    Index *pIdx;                 /* The index we will be using */
    int iIdxCur;                 /* The VDBE cursor for the index */
    int nExtraReg = 0;           /* Number of extra registers needed */
    int op;                      /* Instruction opcode */
    char *zStartAff;             /* Affinity for start of range constraint */
    char *zEndAff;               /* Affinity for end of range constraint */
    int regEndKey;               /* Register for end-key */
    int iIneq;                   /* The table column subject to inequality */
    Index *pPk;                  /* Primary key index on same table as pIdx */

    pIdx = pLoop->u.btree.pIndex;
    pPk = sqlite4FindPrimaryKey(pIdx->pTable, 0);
    iIneq = idxColumnNumber(pIdx, pPk, nEq);
    iIdxCur = pLevel->iIdxCur;
    assert( iCur==pLevel->iTabCur );

    /* If this loop satisfies a sort order (pOrderBy) request that 
    ** was passed to this function to implement a "SELECT min(x) ..." 
    ** query, then the caller will only allow the loop to run for
    ** a single iteration. This means that the first row returned
    ** should not have a NULL value stored in 'x'. If column 'x' is
    ** the first one after the nEq equality constraints in the index,
    ** this requires some special handling.
    */
    if( (pWInfo->wctrlFlags&WHERE_ORDERBY_MIN)!=0
     && (pWInfo->bOBSat!=0)
     && (pIdx->nColumn>nEq)
    ){
      /* assert( pOrderBy->nExpr==1 ); */
      /* assert( pOrderBy->a[0].pExpr->iColumn==pIdx->aiColumn[nEq] ); */
      isMinQuery = 1;
      nExtraReg = 1;
    }

    /* Find any inequality constraint terms for the start and end 
    ** of the range. 
    */
    j = nEq;
    if( pLoop->wsFlags & WHERE_BTM_LIMIT ){
      pRangeStart = pLoop->aLTerm[j++];
      nExtraReg = 1;
    }
    if( pLoop->wsFlags & WHERE_TOP_LIMIT ){
      pRangeEnd = pLoop->aLTerm[j++];
      nExtraReg = 1;
    }

    /* Generate code to evaluate all constraint terms using == or IN
    ** and store the values of those terms in an array of registers
    ** starting at regBase.

    */
    regBase = codeAllEqualityTerms(pParse,pLevel,bRev,nExtraReg,&zStartAff);


    assert( (regBase+nEq+nExtraReg-1)<=pParse->nMem );

    zEndAff = sqlite4DbStrDup(pParse->db, zStartAff);
    addrNxt = pLevel->addrNxt;

    /* If we are doing a reverse order scan on an ascending index, or
    ** a forward order scan on a descending index, interchange the 
    ** start and end terms (pRangeStart and pRangeEnd).
    */
    if( (nEq<pIdx->nColumn && bRev==(pIdx->aSortOrder[nEq]==SQLITE4_SO_ASC))
     || (bRev && pIdx->nColumn==nEq)
    ){
      SWAP(WhereTerm *, pRangeEnd, pRangeStart);
    }

    testcase( pRangeStart && (pRangeStart->eOperator & WO_LE)!=0 );
    testcase( pRangeStart && (pRangeStart->eOperator & WO_GE)!=0 );
    testcase( pRangeEnd && (pRangeEnd->eOperator & WO_LE)!=0 );
    testcase( pRangeEnd && (pRangeEnd->eOperator & WO_GE)!=0 );
    startEq = !pRangeStart || pRangeStart->eOperator & (WO_LE|WO_GE);
    endEq =   !pRangeEnd || pRangeEnd->eOperator & (WO_LE|WO_GE);
    start_constraints = pRangeStart || nEq>0;

    /* Seek the index cursor to the start of the range. */
    nConstraint = nEq;
    if( pRangeStart ){
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    testcase( op==OP_Rewind );
    testcase( op==OP_Last );
    testcase( op==OP_SeekGt );
    testcase( op==OP_SeekGe );
    testcase( op==OP_SeekLe );
    testcase( op==OP_SeekLt );
    sqlite4VdbeAddOp4Int(v, op, iIdxCur, addrNxt, regBase, nConstraint);
    if( (pIdx->nColumn + (pIdx==pPk ? 0 : pPk->nColumn))>nEq ){
      sqlite4VdbeChangeP5(v, OPFLAG_PARTIALKEY);
    }

    /* Set variable op to the instruction required to determine if the
    ** cursor is passed the end of the range. If the range is unbounded,
    ** then set op to OP_Noop. Nothing to do in this case.  */
    assert( (endEq==0 || endEq==1) );
    op = aEndOp[(pRangeEnd || nEq) * (1 + (endEq+endEq) + bRev)];
    testcase( op==OP_Noop );
    testcase( op==OP_IdxGE );
    testcase( op==OP_IdxLT );
    testcase( op==OP_IdxLE );
    testcase( op==OP_IdxGT );

    if( op!=OP_Noop ){
      /* If there is an inequality at the end of this range, compute its
      ** value here.  */

      nConstraint = nEq;
      if( pRangeEnd ){
        Expr *pRight = pRangeEnd->pExpr->pRight;
        sqlite4ExprCacheRemove(pParse, regBase+nEq, 1);
        sqlite4ExprCode(pParse, pRight, regBase+nEq);
        if( (pRangeEnd->wtFlags & TERM_VNULL)==0 ){
          sqlite4ExprCodeIsNullJump(v, pRight, regBase+nEq, addrNxt);
        }
        if( zEndAff ){
          if( sqlite4CompareAffinity(pRight, zEndAff[nEq])==SQLITE4_AFF_NONE){
            /* Since the comparison is to be performed with no conversions
             ** applied to the operands, set the affinity to apply to pRight to 
             ** SQLITE4_AFF_NONE.  */
            zEndAff[nEq] = SQLITE4_AFF_NONE;
          }
          if( sqlite4ExprNeedsNoAffinityChange(pRight, zEndAff[nEq]) ){
            zEndAff[nEq] = SQLITE4_AFF_NONE;
          }
        }  
        codeApplyAffinity(pParse, regBase, nEq+1, zEndAff);
        nConstraint++;
        testcase( pRangeEnd->wtFlags & TERM_VIRTUAL ); /* EV: R-30575-11662 */
      }

      /* Now compute an end-key using OP_MakeIdxKey */
      regEndKey = ++pParse->nMem;
      sqlite4VdbeAddOp4Int(
          v, OP_MakeIdxKey, iIdxCur, regBase, regEndKey, nConstraint
      );

    }

    sqlite4DbFree(pParse->db, zStartAff);
    sqlite4DbFree(pParse->db, zEndAff);

    /* Top of the loop body */
    pLevel->p2 = sqlite4VdbeCurrentAddr(v);







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    testcase( op==OP_Rewind );
    testcase( op==OP_Last );
    testcase( op==OP_SeekGt );
    testcase( op==OP_SeekGe );
    testcase( op==OP_SeekLe );
    testcase( op==OP_SeekLt );
    sqlite4VdbeAddOp4Int(v, op, iIdxCur, addrNxt, regBase, nConstraint);
    if( nEq<idxColumnCount(pIdx, pPk) ){
      sqlite4VdbeChangeP5(v, OPFLAG_PARTIALKEY);
    }

    /* Set variable op to the instruction required to determine if the
    ** cursor is passed the end of the range. If the range is unbounded,
    ** then set op to OP_Noop. Nothing to do in this case.  */
    assert( (endEq==0 || endEq==1) );
    op = aEndOp[(pRangeEnd || nEq) * (1 + (endEq+endEq) + bRev)];
    testcase( op==OP_Noop );
    testcase( op==OP_IdxGE );
    testcase( op==OP_IdxLT );
    testcase( op==OP_IdxLE );
    testcase( op==OP_IdxGT );

    if( op!=OP_Noop ){
      /* Load the value for the inequality constraint at the end of the
      ** range (if any).
      */
      nConstraint = nEq;
      if( pRangeEnd ){
        Expr *pRight = pRangeEnd->pExpr->pRight;
        sqlite4ExprCacheRemove(pParse, regBase+nEq, 1);
        sqlite4ExprCode(pParse, pRight, regBase+nEq);
        if( (pRangeEnd->wtFlags & TERM_VNULL)==0 ){
          sqlite4ExprCodeIsNullJump(v, pRight, regBase+nEq, addrNxt);
        }
        if( zEndAff ){
          if( sqlite4CompareAffinity(pRight, zEndAff[nEq])==SQLITE4_AFF_NONE){
            /* Since the comparison is to be performed with no conversions
            ** applied to the operands, set the affinity to apply to pRight to 
            ** SQLITE4_AFF_NONE.  */
            zEndAff[nEq] = SQLITE4_AFF_NONE;
          }
          if( sqlite4ExprNeedsNoAffinityChange(pRight, zEndAff[nEq]) ){
            zEndAff[nEq] = SQLITE4_AFF_NONE;
          }
        }  
        codeApplyAffinity(pParse, regBase, nEq+1, zEndAff);
        nConstraint++;
        testcase( pRangeEnd->wtFlags & TERM_VIRTUAL ); /* EV: R-30575-11662 */
      }

      /* Now compute an end-key using OP_MakeIdxKey */
      regEndKey = ++pParse->nMem;
      sqlite4VdbeAddOp4Int(
          v, OP_MakeIdxKey, iIdxCur, regBase, regEndKey, nConstraint
      );

    }

    sqlite4DbFree(pParse->db, zStartAff);
    sqlite4DbFree(pParse->db, zEndAff);

    /* Top of the loop body */
    pLevel->p2 = sqlite4VdbeCurrentAddr(v);
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    if( pIdx->eIndexType!=SQLITE4_INDEX_PRIMARYKEY
     && pIdx->eIndexType!=SQLITE4_INDEX_TEMP
    ){
      sqlite4VdbeAddOp3(v, OP_SeekPk, iCur, 0, iIdxCur);
    }

    /* If there are inequality constraints, check that the value
    ** of the table column that the inequality constrains is not NULL.
    ** If it is, jump to the next iteration of the loop.  */

    r1 = sqlite4GetTempReg(pParse);
    testcase( pLevel->plan.wsFlags & WHERE_BTM_LIMIT );
    testcase( pLevel->plan.wsFlags & WHERE_TOP_LIMIT );
    if( (pLevel->plan.wsFlags & (WHERE_BTM_LIMIT|WHERE_TOP_LIMIT))!=0 ){
      sqlite4ExprCodeGetColumnOfTable(v, pIdx->pTable, iCur, iIneq, r1);
      sqlite4VdbeAddOp2(v, OP_IsNull, r1, addrCont);
    }
    sqlite4ReleaseTempReg(pParse, r1);

    /* Record the instruction used to terminate the loop. Disable 
    ** WHERE clause terms made redundant by the index range scan.
    */
    if( pLevel->plan.wsFlags & WHERE_UNIQUE ){
      pLevel->op = OP_Noop;
    }else if( bRev ){
      pLevel->op = OP_Prev;
    }else{
      pLevel->op = OP_Next;
    }
    pLevel->p1 = iIdxCur;





  }else

#ifndef SQLITE4_OMIT_OR_OPTIMIZATION
  if( pLevel->plan.wsFlags & WHERE_MULTI_OR ){
    /* Case 4:  Two or more separately indexed terms connected by OR
    **
    ** Example:
    **
    **   CREATE TABLE t1(a,b,c,d);
    **   CREATE INDEX i1 ON t1(a);
    **   CREATE INDEX i2 ON t1(b);
    **   CREATE INDEX i3 ON t1(c);







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    if( pIdx->eIndexType!=SQLITE4_INDEX_PRIMARYKEY
     && pIdx->eIndexType!=SQLITE4_INDEX_TEMP
    ){
      sqlite4VdbeAddOp3(v, OP_SeekPk, iCur, 0, iIdxCur);
    }

    /* If there are inequality constraints, check that the value
    ** of the table column that the inequality contrains is not NULL.
    ** If it is, jump to the next iteration of the loop.
    */
    r1 = sqlite4GetTempReg(pParse);
    testcase( pLoop->wsFlags & WHERE_BTM_LIMIT );
    testcase( pLoop->wsFlags & WHERE_TOP_LIMIT );
    if( (pLoop->wsFlags & (WHERE_BTM_LIMIT|WHERE_TOP_LIMIT))!=0 ){
      sqlite4ExprCodeGetColumnOfTable(v, pIdx->pTable, iCur, iIneq, r1);
      sqlite4VdbeAddOp2(v, OP_IsNull, r1, addrCont);
    }
    sqlite4ReleaseTempReg(pParse, r1);

    /* Record the instruction used to terminate the loop. Disable 
    ** WHERE clause terms made redundant by the index range scan.
    */
    if( pLoop->wsFlags & WHERE_ONEROW ){
      pLevel->op = OP_Noop;
    }else if( bRev ){
      pLevel->op = OP_Prev;
    }else{
      pLevel->op = OP_Next;
    }
    pLevel->p1 = iIdxCur;
    if( (pLoop->wsFlags & WHERE_CONSTRAINT)==0 ){
      pLevel->p5 = SQLITE4_STMTSTATUS_FULLSCAN_STEP;
    }else{
      assert( pLevel->p5==0 );
    }
  }else

#ifndef SQLITE4_OMIT_OR_OPTIMIZATION
  if( pLoop->wsFlags & WHERE_MULTI_OR ){
    /* Case 5:  Two or more separately indexed terms connected by OR
    **
    ** Example:
    **
    **   CREATE TABLE t1(a,b,c,d);
    **   CREATE INDEX i1 ON t1(a);
    **   CREATE INDEX i2 ON t1(b);
    **   CREATE INDEX i3 ON t1(c);
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    **          Return     2                # Jump back to the Gosub
    **
    **       B: <after the loop>
    **
    */
    WhereClause *pOrWc;    /* The OR-clause broken out into subterms */
    SrcList *pOrTab;       /* Shortened table list or OR-clause generation */



    int regReturn = ++pParse->nMem;           /* Register used with OP_Gosub */
    int regKeyset = 0;                        /* Register for RowSet object */
    int regKey = 0;                           /* Register holding key */
    int iLoopBody = sqlite4VdbeMakeLabel(v);  /* Start of loop body */
    int iRetInit;                             /* Address of regReturn init */
    int untestedTerms = 0;             /* Some terms not completely tested */
    int ii;                            /* Loop counter */
    Expr *pAndExpr = 0;                /* An ".. AND (...)" expression */
   
    pTerm = pLevel->plan.u.pTerm;
    assert( pTerm!=0 );
    assert( pTerm->eOperator==WO_OR );
    assert( (pTerm->wtFlags & TERM_ORINFO)!=0 );
    pOrWc = &pTerm->u.pOrInfo->wc;
    pLevel->op = OP_Return;
    pLevel->p1 = regReturn;

    /* Set up a new SrcList in pOrTab containing the table being scanned
    ** by this loop in the a[0] slot and all notReady tables in a[1..] slots.
    ** This becomes the SrcList in the recursive call to sqlite4WhereBegin().
    */
    if( pWInfo->nLevel>1 ){
      int nNotReady;                 /* The number of notReady tables */
      SrcListItem *origSrc;     /* Original list of tables */
      nNotReady = pWInfo->nLevel - iLevel - 1;
      pOrTab = sqlite4StackAllocRaw(pParse->db,
                            sizeof(*pOrTab)+ nNotReady*sizeof(pOrTab->a[0]));
      if( pOrTab==0 ) return notReady;
      pOrTab->nAlloc = (i16)(nNotReady + 1);
      pOrTab->nSrc = pOrTab->nAlloc;
      memcpy(pOrTab->a, pTabItem, sizeof(*pTabItem));
      origSrc = pWInfo->pTabList->a;
      for(k=1; k<=nNotReady; k++){
        memcpy(&pOrTab->a[k], &origSrc[pLevel[k].iFrom], sizeof(pOrTab->a[k]));
      }
    }else{
      pOrTab = pWInfo->pTabList;
    }

    /* Initialize the keyset register to contain NULL. An SQL NULL is 
    ** equivalent to an empty rowset.
    **
    ** Also initialize regReturn to contain the address of the instruction 
    ** immediately following the OP_Return at the bottom of the loop. This
    ** is required in a few obscure LEFT JOIN cases where control jumps
    ** over the top of the loop into the body of it. In this case the 
    ** correct response for the end-of-loop code (the OP_Return) is to 
    ** fall through to the next instruction, just as an OP_Next does if
    ** called on an uninitialized cursor.
    */
    if( (wctrlFlags & WHERE_DUPLICATES_OK)==0 ){
      regKeyset = ++pParse->nMem;
      regKey = ++pParse->nMem;
      sqlite4VdbeAddOp2(v, OP_Null, 0, regKeyset);
    }
    iRetInit = sqlite4VdbeAddOp2(v, OP_Integer, 0, regReturn);

    /* If the original WHERE clause is z of the form:  (x1 OR x2 OR ...) AND y
    ** Then for every term xN, evaluate as the subexpression: xN AND z
    ** That way, terms in y that are factored into the disjunction will
    ** be picked up by the recursive calls to sqlite4WhereBegin() below.









    */
    if( pWC->nTerm>1 ){







      pAndExpr = sqlite4ExprAlloc(pParse->db, TK_AND, 0, 0);

      pAndExpr->pRight = pWhere;


    }

    for(ii=0; ii<pOrWc->nTerm; ii++){
      WhereTerm *pOrTerm = &pOrWc->a[ii];
      if( pOrTerm->leftCursor==iCur || pOrTerm->eOperator==WO_AND ){
        WhereInfo *pSubWInfo;          /* Info for single OR-term scan */
        Expr *pOrExpr = pOrTerm->pExpr;
        if( pAndExpr ){
          pAndExpr->pLeft = pOrExpr;
          pOrExpr = pAndExpr;
        }
        /* Loop through table entries that match term pOrTerm. */
        pSubWInfo = sqlite4WhereBegin(pParse, pOrTab, pOrExpr, 0, 0,
                        WHERE_OMIT_OPEN_CLOSE | WHERE_AND_ONLY |
                        WHERE_NO_AUTOINDEX | WHERE_ONETABLE_ONLY);

        if( pSubWInfo ){

          explainOneScan(
              pParse, pOrTab, &pSubWInfo->a[0], iLevel, pLevel->iFrom, 0
          );
          if( (wctrlFlags & WHERE_DUPLICATES_OK)==0 ){
            int addrJump;
            sqlite4VdbeAddOp2(v, OP_RowKey, iCur, regKey);
            addrJump = sqlite4VdbeCurrentAddr(v) + 2;
            sqlite4VdbeAddOp4Int(v, OP_RowSetTest, 
                regKeyset, addrJump, regKey, ((ii==pOrWc->nTerm-1)?-1:ii)
            );
          }
          sqlite4VdbeAddOp2(v, OP_Gosub, regReturn, iLoopBody);

          /* The pSubWInfo->untestedTerms flag means that this OR term
          ** contained one or more AND term from a notReady table.  The
          ** terms from the notReady table could not be tested and will
          ** need to be tested later.
          */
          if( pSubWInfo->untestedTerms ) untestedTerms = 1;


























          /* Finish the loop through table entries that match term pOrTerm. */
          sqlite4WhereEnd(pSubWInfo);
        }
      }
    }




    sqlite4DbFree(pParse->db, pAndExpr);

    sqlite4VdbeChangeP1(v, iRetInit, sqlite4VdbeCurrentAddr(v));
    sqlite4VdbeAddOp2(v, OP_Goto, 0, pLevel->addrBrk);
    sqlite4VdbeResolveLabel(v, iLoopBody);

    if( pWInfo->nLevel>1 ) sqlite4StackFree(pParse->db, pOrTab);
    if( !untestedTerms ) disableTerm(pLevel, pTerm);
  }else
#endif /* SQLITE4_OMIT_OR_OPTIMIZATION */

  {



    /* Case 5:  There is no usable index.  We must do a complete
    **          scan of the entire table.
    */
    static const u8 aStep[] = { OP_Next, OP_Prev };
    static const u8 aStart[] = { OP_Rewind, OP_Last };
    assert( bRev==0 || bRev==1 );
    pLevel->op = aStep[bRev];
    pLevel->p1 = iCur;
    pLevel->p2 = 1 + sqlite4VdbeAddOp2(v, aStart[bRev], iCur, addrBrk);
    pLevel->p5 = SQLITE4_STMTSTATUS_FULLSCAN_STEP;
  }
  notReady &= ~getMask(pWC->pMaskSet, iCur);

  /* Insert code to test every subexpression that can be completely
  ** computed using the current set of tables.
  **
  ** IMPLEMENTATION-OF: R-49525-50935 Terms that cannot be satisfied through
  ** the use of indices become tests that are evaluated against each row of
  ** the relevant input tables.
  */
  for(pTerm=pWC->a, j=pWC->nTerm; j>0; j--, pTerm++){
    Expr *pE;
    testcase( pTerm->wtFlags & TERM_VIRTUAL ); /* IMP: R-30575-11662 */
    testcase( pTerm->wtFlags & TERM_CODED );
    if( pTerm->wtFlags & (TERM_VIRTUAL|TERM_CODED) ) continue;
    if( (pTerm->prereqAll & notReady)!=0 ){
      testcase( pWInfo->untestedTerms==0
               && (pWInfo->wctrlFlags & WHERE_ONETABLE_ONLY)!=0 );
      pWInfo->untestedTerms = 1;
      continue;
    }
    pE = pTerm->pExpr;
    assert( pE!=0 );
    if( pLevel->iLeftJoin && !ExprHasProperty(pE, EP_FromJoin) ){
      continue;
    }
    sqlite4ExprIfFalse(pParse, pE, addrCont, SQLITE4_JUMPIFNULL);
    pTerm->wtFlags |= TERM_CODED;
  }































  /* For a LEFT OUTER JOIN, generate code that will record the fact that
  ** at least one row of the right table has matched the left table.  
  */
  if( pLevel->iLeftJoin ){
    pLevel->addrFirst = sqlite4VdbeCurrentAddr(v);
    sqlite4VdbeAddOp2(v, OP_Integer, 1, pLevel->iLeftJoin);
    VdbeComment((v, "record LEFT JOIN hit"));
    sqlite4ExprCacheClear(pParse);
    for(pTerm=pWC->a, j=0; j<pWC->nTerm; j++, pTerm++){
      testcase( pTerm->wtFlags & TERM_VIRTUAL );  /* IMP: R-30575-11662 */
      testcase( pTerm->wtFlags & TERM_CODED );
      if( pTerm->wtFlags & (TERM_VIRTUAL|TERM_CODED) ) continue;
      if( (pTerm->prereqAll & notReady)!=0 ){
        assert( pWInfo->untestedTerms );
        continue;
      }
      assert( pTerm->pExpr );
      sqlite4ExprIfFalse(pParse, pTerm->pExpr, addrCont, SQLITE4_JUMPIFNULL);
      pTerm->wtFlags |= TERM_CODED;
    }
  }
  sqlite4ReleaseTempReg(pParse, iReleaseReg);

  return notReady;
}







































































#if defined(SQLITE4_TEST)
/*







** The following variable holds a text description of query plan generated




** by the most recent call to sqlite4WhereBegin().  Each call to WhereBegin










** overwrites the previous.  This information is used for testing and
** analysis only.


*/
char sqlite4_query_plan[BMS*2*40];  /* Text of the join */





static int nQPlan = 0;              /* Next free slow in _query_plan[] */



#endif /* SQLITE4_TEST */










/*
** Free a WhereInfo structure
*/
static void whereInfoFree(sqlite4 *db, WhereInfo *pWInfo){
  if( ALWAYS(pWInfo) ){
    int i;
    for(i=0; i<pWInfo->nLevel; i++){
      sqlite4_index_info *pInfo = pWInfo->a[i].pIdxInfo;
      if( pInfo ){
        /* assert( pInfo->needToFreeIdxStr==0 || db->mallocFailed ); */
        if( pInfo->needToFreeIdxStr ){
          sqlite4_free(db->pEnv, pInfo->idxStr);
        }
        sqlite4DbFree(db, pInfo);
      }
      if( pWInfo->a[i].plan.wsFlags & WHERE_TEMP_INDEX ){
        Index *pIdx = pWInfo->a[i].plan.u.pIdx;
        if( pIdx ){
          assert( pIdx->eIndexType==SQLITE4_INDEX_TEMP );
          sqlite4DbFree(db, pIdx->zColAff);
          sqlite4DbFree(db, pIdx);
        }
      }
    }
    whereClauseClear(pWInfo->pWC);
    sqlite4DbFree(db, pWInfo);
  }
}





























































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































/*
** Generate the beginning of the loop used for WHERE clause processing.
** The return value is a pointer to an opaque structure that contains
** information needed to terminate the loop.  Later, the calling routine
** should invoke sqlite4WhereEnd() with the return value of this function
** in order to complete the WHERE clause processing.







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    **          Return     2                # Jump back to the Gosub
    **
    **       B: <after the loop>
    **
    */
    WhereClause *pOrWc;    /* The OR-clause broken out into subterms */
    SrcList *pOrTab;       /* Shortened table list or OR-clause generation */
    Index *pCov = 0;             /* Potential covering index (or NULL) */
    int iCovCur = pParse->nTab++;  /* Cursor used for index scans (if any) */

    int regReturn = ++pParse->nMem;           /* Register used with OP_Gosub */
    int regKeyset = 0;                        /* Register for RowSet object */
    int regKey = 0;                           /* Register holding key */
    int iLoopBody = sqlite4VdbeMakeLabel(v);  /* Start of loop body */
    int iRetInit;                             /* Address of regReturn init */
    int untestedTerms = 0;             /* Some terms not completely tested */
    int ii;                            /* Loop counter */
    Expr *pAndExpr = 0;                /* An ".. AND (...)" expression */
   
    pTerm = pLoop->aLTerm[0];
    assert( pTerm!=0 );
    assert( pTerm->eOperator & WO_OR );
    assert( (pTerm->wtFlags & TERM_ORINFO)!=0 );
    pOrWc = &pTerm->u.pOrInfo->wc;
    pLevel->op = OP_Return;
    pLevel->p1 = regReturn;

    /* Set up a new SrcList in pOrTab containing the table being scanned
    ** by this loop in the a[0] slot and all notReady tables in a[1..] slots.
    ** This becomes the SrcList in the recursive call to sqlite4WhereBegin().
    */
    if( pWInfo->nLevel>1 ){
      int nNotReady;                 /* The number of notReady tables */
      struct SrcListItem *origSrc;     /* Original list of tables */
      nNotReady = pWInfo->nLevel - iLevel - 1;
      pOrTab = sqlite4StackAllocRaw(pParse->db,
                            sizeof(*pOrTab)+ nNotReady*sizeof(pOrTab->a[0]));
      if( pOrTab==0 ) return notReady;
      pOrTab->nAlloc = (u8)(nNotReady + 1);
      pOrTab->nSrc = pOrTab->nAlloc;
      memcpy(pOrTab->a, pTabItem, sizeof(*pTabItem));
      origSrc = pWInfo->pTabList->a;
      for(k=1; k<=nNotReady; k++){
        memcpy(&pOrTab->a[k], &origSrc[pLevel[k].iFrom], sizeof(pOrTab->a[k]));
      }
    }else{
      pOrTab = pWInfo->pTabList;
    }

    /* Initialize the keyset register to contain NULL. An SQL NULL is 
    ** equivalent to an empty keyset.
    **
    ** Also initialize regReturn to contain the address of the instruction 
    ** immediately following the OP_Return at the bottom of the loop. This
    ** is required in a few obscure LEFT JOIN cases where control jumps
    ** over the top of the loop into the body of it. In this case the 
    ** correct response for the end-of-loop code (the OP_Return) is to 
    ** fall through to the next instruction, just as an OP_Next does if
    ** called on an uninitialized cursor.
    */
    if( (pWInfo->wctrlFlags & WHERE_DUPLICATES_OK)==0 ){
      regKeyset = ++pParse->nMem;
      regKey = ++pParse->nMem;
      sqlite4VdbeAddOp2(v, OP_Null, 0, regKeyset);
    }
    iRetInit = sqlite4VdbeAddOp2(v, OP_Integer, 0, regReturn);

    /* If the original WHERE clause is z of the form:  (x1 OR x2 OR ...) AND y
    ** Then for every term xN, evaluate as the subexpression: xN AND z
    ** That way, terms in y that are factored into the disjunction will
    ** be picked up by the recursive calls to sqlite4WhereBegin() below.
    **
    ** Actually, each subexpression is converted to "xN AND w" where w is
    ** the "interesting" terms of z - terms that did not originate in the
    ** ON or USING clause of a LEFT JOIN, and terms that are usable as 
    ** indices.
    **
    ** This optimization also only applies if the (x1 OR x2 OR ...) term
    ** is not contained in the ON clause of a LEFT JOIN.
    ** See ticket http://www.sqlite.org/src/info/f2369304e4
    */
    if( pWC->nTerm>1 ){
      int iTerm;
      for(iTerm=0; iTerm<pWC->nTerm; iTerm++){
        Expr *pExpr = pWC->a[iTerm].pExpr;
        if( ExprHasProperty(pExpr, EP_FromJoin) ) continue;
        if( pWC->a[iTerm].wtFlags & (TERM_VIRTUAL|TERM_ORINFO) ) continue;
        if( (pWC->a[iTerm].eOperator & WO_ALL)==0 ) continue;
        pExpr = sqlite4ExprDup(pParse->db, pExpr, 0);
        pAndExpr = sqlite4ExprAnd(pParse->db, pAndExpr, pExpr);
      }
      if( pAndExpr ){
        pAndExpr = sqlite4PExpr(pParse, TK_AND, 0, pAndExpr, 0);
      }
    }

    for(ii=0; ii<pOrWc->nTerm; ii++){
      WhereTerm *pOrTerm = &pOrWc->a[ii];
      if( pOrTerm->leftCursor==iCur || (pOrTerm->eOperator & WO_AND)!=0 ){
        WhereInfo *pSubWInfo;          /* Info for single OR-term scan */
        Expr *pOrExpr = pOrTerm->pExpr;
        if( pAndExpr && !ExprHasProperty(pOrExpr, EP_FromJoin) ){
          pAndExpr->pLeft = pOrExpr;
          pOrExpr = pAndExpr;
        }
        /* Loop through table entries that match term pOrTerm. */
        pSubWInfo = sqlite4WhereBegin(pParse, pOrTab, pOrExpr, 0, 0,
                        WHERE_OMIT_OPEN_CLOSE | WHERE_AND_ONLY |
                        WHERE_FORCE_TABLE | WHERE_ONETABLE_ONLY, iCovCur);
        assert( pSubWInfo || pParse->nErr || pParse->db->mallocFailed );
        if( pSubWInfo ){
          WhereLoop *pSubLoop;
          explainOneScan(
              pParse, pOrTab, &pSubWInfo->a[0], iLevel, pLevel->iFrom, 0
          );
          if( (pWInfo->wctrlFlags & WHERE_DUPLICATES_OK)==0 ){
            int iSet = ((ii==pOrWc->nTerm-1)?-1:ii);
            sqlite4VdbeAddOp2(v, OP_RowKey, iCur, regKey);

            sqlite4VdbeAddOp4Int(v, OP_RowSetTest, regKeyset,
                                 sqlite4VdbeCurrentAddr(v)+2, regKey, iSet);

          }
          sqlite4VdbeAddOp2(v, OP_Gosub, regReturn, iLoopBody);

          /* The pSubWInfo->untestedTerms flag means that this OR term
          ** contained one or more AND term from a notReady table.  The
          ** terms from the notReady table could not be tested and will
          ** need to be tested later.
          */
          if( pSubWInfo->untestedTerms ) untestedTerms = 1;

          /* If all of the OR-connected terms are optimized using the same
          ** index, and the index is opened using the same cursor number
          ** by each call to sqlite4WhereBegin() made by this loop, it may
          ** be possible to use that index as a covering index.
          **
          ** If the call to sqlite4WhereBegin() above resulted in a scan that
          ** uses an index, and this is either the first OR-connected term
          ** processed or the index is the same as that used by all previous
          ** terms, set pCov to the candidate covering index. Otherwise, set 
          ** pCov to NULL to indicate that no candidate covering index will 
          ** be available.
          */
#if 0
          pSubLoop = pSubWInfo->a[0].pWLoop;
          assert( (pSubLoop->wsFlags & WHERE_AUTO_INDEX)==0 );
          if( (pSubLoop->wsFlags & WHERE_INDEXED)!=0
           && (ii==0 || pSubLoop->u.btree.pIndex==pCov)
          ){
            assert( pSubWInfo->a[0].iIdxCur==iCovCur );
            pCov = pSubLoop->u.btree.pIndex;
          }else{
            pCov = 0;
          }
#endif

          /* Finish the loop through table entries that match term pOrTerm. */
          sqlite4WhereEnd(pSubWInfo);
        }
      }
    }
    pLevel->u.pCovidx = pCov;
    if( pCov ) pLevel->iIdxCur = iCovCur;
    if( pAndExpr ){
      pAndExpr->pLeft = 0;
      sqlite4ExprDelete(pParse->db, pAndExpr);
    }
    sqlite4VdbeChangeP1(v, iRetInit, sqlite4VdbeCurrentAddr(v));
    sqlite4VdbeAddOp2(v, OP_Goto, 0, pLevel->addrBrk);
    sqlite4VdbeResolveLabel(v, iLoopBody);

    if( pWInfo->nLevel>1 ) sqlite4StackFree(pParse->db, pOrTab);
    if( !untestedTerms ) disableTerm(pLevel, pTerm);
  }else
#endif /* SQLITE4_OMIT_OR_OPTIMIZATION */

  {
    /* TODO: This case is currently being used. Why can't it use the 
    ** index case instead? */ 

    /* Case 6:  There is no usable index.  We must do a complete
    **          scan of the entire table.
    */
    static const u8 aStep[] = { OP_Next, OP_Prev };
    static const u8 aStart[] = { OP_Rewind, OP_Last };
    assert( bRev==0 || bRev==1 );
    pLevel->op = aStep[bRev];
    pLevel->p1 = iCur;
    pLevel->p2 = 1 + sqlite4VdbeAddOp2(v, aStart[bRev], iCur, addrBrk);
    pLevel->p5 = SQLITE4_STMTSTATUS_FULLSCAN_STEP;
  }
  newNotReady = notReady & ~getMask(&pWInfo->sMaskSet, iCur);

  /* Insert code to test every subexpression that can be completely
  ** computed using the current set of tables.
  **
  ** IMPLEMENTATION-OF: R-49525-50935 Terms that cannot be satisfied through
  ** the use of indices become tests that are evaluated against each row of
  ** the relevant input tables.
  */
  for(pTerm=pWC->a, j=pWC->nTerm; j>0; j--, pTerm++){
    Expr *pE;
    testcase( pTerm->wtFlags & TERM_VIRTUAL ); /* IMP: R-30575-11662 */
    testcase( pTerm->wtFlags & TERM_CODED );
    if( pTerm->wtFlags & (TERM_VIRTUAL|TERM_CODED) ) continue;
    if( (pTerm->prereqAll & newNotReady)!=0 ){
      testcase( pWInfo->untestedTerms==0
               && (pWInfo->wctrlFlags & WHERE_ONETABLE_ONLY)!=0 );
      pWInfo->untestedTerms = 1;
      continue;
    }
    pE = pTerm->pExpr;
    assert( pE!=0 );
    if( pLevel->iLeftJoin && !ExprHasProperty(pE, EP_FromJoin) ){
      continue;
    }
    sqlite4ExprIfFalse(pParse, pE, addrCont, SQLITE4_JUMPIFNULL);
    pTerm->wtFlags |= TERM_CODED;
  }

  /* Insert code to test for implied constraints based on transitivity
  ** of the "==" operator.
  **
  ** Example: If the WHERE clause contains "t1.a=t2.b" and "t2.b=123"
  ** and we are coding the t1 loop and the t2 loop has not yet coded,
  ** then we cannot use the "t1.a=t2.b" constraint, but we can code
  ** the implied "t1.a=123" constraint.
  */
  for(pTerm=pWC->a, j=pWC->nTerm; j>0; j--, pTerm++){
    Expr *pE;
    WhereTerm *pAlt;
    Expr sEq;
    if( pTerm->wtFlags & (TERM_VIRTUAL|TERM_CODED) ) continue;
    if( pTerm->eOperator!=(WO_EQUIV|WO_EQ) ) continue;
    if( pTerm->leftCursor!=iCur ) continue;
    if( pLevel->iLeftJoin ) continue;
    pE = pTerm->pExpr;
    assert( !ExprHasProperty(pE, EP_FromJoin) );
    assert( (pTerm->prereqRight & newNotReady)!=0 );
    pAlt = findTerm(pWC, iCur, pTerm->u.leftColumn, notReady, WO_EQ|WO_IN, 0);
    if( pAlt==0 ) continue;
    if( pAlt->wtFlags & (TERM_CODED) ) continue;
    testcase( pAlt->eOperator & WO_EQ );
    testcase( pAlt->eOperator & WO_IN );
    VdbeNoopComment((v, "begin transitive constraint"));
    sEq = *pAlt->pExpr;
    sEq.pLeft = pE->pLeft;
    sqlite4ExprIfFalse(pParse, &sEq, addrCont, SQLITE4_JUMPIFNULL);
  }

  /* For a LEFT OUTER JOIN, generate code that will record the fact that
  ** at least one row of the right table has matched the left table.  
  */
  if( pLevel->iLeftJoin ){
    pLevel->addrFirst = sqlite4VdbeCurrentAddr(v);
    sqlite4VdbeAddOp2(v, OP_Integer, 1, pLevel->iLeftJoin);
    VdbeComment((v, "record LEFT JOIN hit"));
    sqlite4ExprCacheClear(pParse);
    for(pTerm=pWC->a, j=0; j<pWC->nTerm; j++, pTerm++){
      testcase( pTerm->wtFlags & TERM_VIRTUAL );  /* IMP: R-30575-11662 */
      testcase( pTerm->wtFlags & TERM_CODED );
      if( pTerm->wtFlags & (TERM_VIRTUAL|TERM_CODED) ) continue;
      if( (pTerm->prereqAll & newNotReady)!=0 ){
        assert( pWInfo->untestedTerms );
        continue;
      }
      assert( pTerm->pExpr );
      sqlite4ExprIfFalse(pParse, pTerm->pExpr, addrCont, SQLITE4_JUMPIFNULL);
      pTerm->wtFlags |= TERM_CODED;
    }
  }
  sqlite4ReleaseTempReg(pParse, iReleaseReg);

  return newNotReady;
}

#ifdef WHERETRACE_ENABLED
/*
** Print a WhereLoop object for debugging purposes
*/
static void whereLoopPrint(WhereLoop *p, SrcList *pTabList){
  int nb = 1+(pTabList->nSrc+7)/8;
  struct SrcListItem *pItem = pTabList->a + p->iTab;
  Table *pTab = pItem->pTab;
  sqlite4DebugPrintf("%c%2d.%0*llx.%0*llx", p->cId,
                     p->iTab, nb, p->maskSelf, nb, p->prereq);
  sqlite4DebugPrintf(" %12s",
                     pItem->zAlias ? pItem->zAlias : pTab->zName);
  if( (p->wsFlags & WHERE_VIRTUALTABLE)==0 ){
    if( p->u.btree.pIndex ){
      const char *zName = p->u.btree.pIndex->zName;
      if( zName==0 ) zName = "ipk";
      if( strncmp(zName, "sqlite_autoindex_", 17)==0 ){
        int i = sqlite4Strlen30(zName) - 1;
        while( zName[i]!='_' ) i--;
        zName += i;
      }
      sqlite4DebugPrintf(".%-16s %2d", zName, p->u.btree.nEq);
    }else{
      sqlite4DebugPrintf("%20s","");
    }
  }else{
    char *z;
    if( p->u.vtab.idxStr ){
      z = sqlite4_mprintf(0, "(%d,\"%s\",%x)",
                p->u.vtab.idxNum, p->u.vtab.idxStr, p->u.vtab.omitMask);
    }else{
      z = sqlite4_mprintf(0, "(%d,%x)", p->u.vtab.idxNum, p->u.vtab.omitMask);
    }
    sqlite4DebugPrintf(" %-19s", z);
    sqlite4_free(0, z);
  }
  sqlite4DebugPrintf(" f %04x N %d", p->wsFlags, p->nLTerm);
  sqlite4DebugPrintf(" cost %d,%d,%d\n", p->rSetup, p->rRun, p->nOut);
}
#endif

/*
** Convert bulk memory into a valid WhereLoop that can be passed
** to whereLoopClear harmlessly.
*/
static void whereLoopInit(WhereLoop *p){
  p->aLTerm = p->aLTermSpace;
  p->nLTerm = 0;
  p->nLSlot = ArraySize(p->aLTermSpace);
  p->wsFlags = 0;
}

/*
** Clear the WhereLoop.u union.  Leave WhereLoop.pLTerm intact.
*/
static void whereLoopClearUnion(sqlite4 *db, WhereLoop *p){
  if( p->wsFlags & (WHERE_VIRTUALTABLE|WHERE_AUTO_INDEX) ){
    if( (p->wsFlags & WHERE_VIRTUALTABLE)!=0 && p->u.vtab.needFree ){
#if 0
      sqlite4_free(p->u.vtab.idxStr);
#endif
      p->u.vtab.needFree = 0;
      p->u.vtab.idxStr = 0;
    }else if( (p->wsFlags & WHERE_AUTO_INDEX)!=0 && p->u.btree.pIndex!=0 ){
      sqlite4DbFree(db, p->u.btree.pIndex->zColAff);
      sqlite4DbFree(db, p->u.btree.pIndex);
      p->u.btree.pIndex = 0;
    }
  }
}

/*
** Deallocate internal memory used by a WhereLoop object
*/
static void whereLoopClear(sqlite4 *db, WhereLoop *p){
  if( p->aLTerm!=p->aLTermSpace ) sqlite4DbFree(db, p->aLTerm);
  whereLoopClearUnion(db, p);
  whereLoopInit(p);
}

/*
** Increase the memory allocation for pLoop->aLTerm[] to be at least n.
*/
static int whereLoopResize(sqlite4 *db, WhereLoop *p, int n){
  WhereTerm **paNew;
  if( p->nLSlot>=n ) return SQLITE4_OK;
  n = (n+7)&~7;
  paNew = sqlite4DbMallocRaw(db, sizeof(p->aLTerm[0])*n);
  if( paNew==0 ) return SQLITE4_NOMEM;
  memcpy(paNew, p->aLTerm, sizeof(p->aLTerm[0])*p->nLSlot);
  if( p->aLTerm!=p->aLTermSpace ) sqlite4DbFree(db, p->aLTerm);
  p->aLTerm = paNew;
  p->nLSlot = n;
  return SQLITE4_OK;
}


/*
** Transfer content from the second pLoop into the first.
*/
static int whereLoopXfer(sqlite4 *db, WhereLoop *pTo, WhereLoop *pFrom){
  if( whereLoopResize(db, pTo, pFrom->nLTerm) ) return SQLITE4_NOMEM;
  whereLoopClearUnion(db, pTo);
  memcpy(pTo, pFrom, WHERE_LOOP_XFER_SZ);
  memcpy(pTo->aLTerm, pFrom->aLTerm, pTo->nLTerm*sizeof(pTo->aLTerm[0]));
  if( pFrom->wsFlags & WHERE_VIRTUALTABLE ){
    pFrom->u.vtab.needFree = 0;
  }else if( (pFrom->wsFlags & WHERE_AUTO_INDEX)!=0 ){
    pFrom->u.btree.pIndex = 0;
  }
  return SQLITE4_OK;
}

/*
** Delete a WhereLoop object
*/
static void whereLoopDelete(sqlite4 *db, WhereLoop *p){
  whereLoopClear(db, p);
  sqlite4DbFree(db, p);
}

/*
** Free a WhereInfo structure
*/
static void whereInfoFree(sqlite4 *db, WhereInfo *pWInfo){
  if( ALWAYS(pWInfo) ){

    whereClauseClear(&pWInfo->sWC);
    while( pWInfo->pLoops ){







      WhereLoop *p = pWInfo->pLoops;
      pWInfo->pLoops = p->pNextLoop;



      whereLoopDelete(db, p);
    }



    sqlite4DbFree(db, pWInfo);
  }
}

/*
** Insert or replace a WhereLoop entry using the template supplied.
**
** An existing WhereLoop entry might be overwritten if the new template
** is better and has fewer dependencies.  Or the template will be ignored
** and no insert will occur if an existing WhereLoop is faster and has
** fewer dependencies than the template.  Otherwise a new WhereLoop is
** added based on the template.
**
** If pBuilder->pBest is not NULL then we only care about the very
** best template and that template should be stored in pBuilder->pBest.
** If pBuilder->pBest is NULL then a list of the best templates are stored
** in pBuilder->pWInfo->pLoops.
**
** When accumulating multiple loops (when pBuilder->pBest is NULL) we
** still might overwrite similar loops with the new template if the
** template is better.  Loops may be overwritten if the following 
** conditions are met:
**
**    (1)  They have the same iTab.
**    (2)  They have the same iSortIdx.
**    (3)  The template has same or fewer dependencies than the current loop
**    (4)  The template has the same or lower cost than the current loop
**    (5)  The template uses more terms of the same index but has no additional
**         dependencies          
*/
static int whereLoopInsert(WhereLoopBuilder *pBuilder, WhereLoop *pTemplate){
  WhereLoop **ppPrev, *p, *pNext = 0;
  WhereInfo *pWInfo = pBuilder->pWInfo;
  sqlite4 *db = pWInfo->pParse->db;

  assert( pTemplate->u.btree.pIndex || !(pTemplate->wsFlags & WHERE_INDEXED) );

  /* If pBuilder->pBest is defined, then only keep track of the single
  ** best WhereLoop.  pBuilder->pBest->maskSelf==0 indicates that no
  ** prior WhereLoops have been evaluated and that the current pTemplate
  ** is therefore the first and hence the best and should be retained.
  */
  if( (p = pBuilder->pBest)!=0 ){
    if( p->maskSelf!=0 ){
      WhereCost rCost = whereCostAdd(p->rRun,p->rSetup);
      WhereCost rTemplate = whereCostAdd(pTemplate->rRun,pTemplate->rSetup);
      if( rCost < rTemplate ){
        testcase( rCost==rTemplate-1 );
        goto whereLoopInsert_noop;
      }
      if( rCost==rTemplate && (p->prereq & pTemplate->prereq)==p->prereq ){
        goto whereLoopInsert_noop;
      }
    }
#if WHERETRACE_ENABLED
    if( sqlite4WhereTrace & 0x8 ){
      sqlite4DebugPrintf(p->maskSelf==0 ? "ins-init: " : "ins-best: ");
      whereLoopPrint(pTemplate, pWInfo->pTabList);
    }
#endif
    whereLoopXfer(db, p, pTemplate);
    return SQLITE4_OK;
  }

  /* Search for an existing WhereLoop to overwrite, or which takes
  ** priority over pTemplate.
  */
  for(ppPrev=&pWInfo->pLoops, p=*ppPrev; p; ppPrev=&p->pNextLoop, p=*ppPrev){
    if( p->iTab!=pTemplate->iTab || p->iSortIdx!=pTemplate->iSortIdx ){
      /* If either the iTab or iSortIdx values for two WhereLoop are different
      ** then those WhereLoops need to be considered separately.  Neither is
      ** a candidate to replace the other. */
      continue;
    }
    /* In the current implementation, the rSetup value is either zero
    ** or the cost of building an automatic index (NlogN) and the NlogN
    ** is the same for compatible WhereLoops. */
    assert( p->rSetup==0 || pTemplate->rSetup==0 
                 || p->rSetup==pTemplate->rSetup );

    /* whereLoopAddBtree() always generates and inserts the automatic index
    ** case first.  Hence compatible candidate WhereLoops never have a larger
    ** rSetup. Call this SETUP-INVARIANT */
    assert( p->rSetup>=pTemplate->rSetup );

    if( (p->prereq & pTemplate->prereq)==p->prereq
     && p->rSetup<=pTemplate->rSetup
     && p->rRun<=pTemplate->rRun
    ){
      /* This branch taken when p is equal or better than pTemplate in 
      ** all of (1) dependences (2) setup-cost, and (3) run-cost. */
      assert( p->rSetup==pTemplate->rSetup );
      if( p->nLTerm<pTemplate->nLTerm
       && (p->wsFlags & WHERE_INDEXED)!=0
       && (pTemplate->wsFlags & WHERE_INDEXED)!=0
       && p->u.btree.pIndex==pTemplate->u.btree.pIndex
       && p->prereq==pTemplate->prereq
      ){
        /* Overwrite an existing WhereLoop with an similar one that uses
        ** more terms of the index */
        pNext = p->pNextLoop;
        break;
      }else{
        /* pTemplate is not helpful.
        ** Return without changing or adding anything */
        goto whereLoopInsert_noop;
      }
    }
    if( (p->prereq & pTemplate->prereq)==pTemplate->prereq
     && p->rRun>=pTemplate->rRun
     && ALWAYS(p->rSetup>=pTemplate->rSetup) /* See SETUP-INVARIANT above */
    ){
      /* Overwrite an existing WhereLoop with a better one: one that is
      ** better at one of (1) dependences, (2) setup-cost, or (3) run-cost
      ** and is no worse in any of those categories. */
      pNext = p->pNextLoop;
      break;
    }
  }

  /* If we reach this point it means that either p[] should be overwritten
  ** with pTemplate[] if p[] exists, or if p==NULL then allocate a new
  ** WhereLoop and insert it.
  */
#if WHERETRACE_ENABLED
  if( sqlite4WhereTrace & 0x8 ){
    if( p!=0 ){
      sqlite4DebugPrintf("ins-del:  ");
      whereLoopPrint(p, pWInfo->pTabList);
    }
    sqlite4DebugPrintf("ins-new:  ");
    whereLoopPrint(pTemplate, pWInfo->pTabList);
  }
#endif
  if( p==0 ){
    p = sqlite4DbMallocRaw(db, sizeof(WhereLoop));
    if( p==0 ) return SQLITE4_NOMEM;
    whereLoopInit(p);
  }
  whereLoopXfer(db, p, pTemplate);
  p->pNextLoop = pNext;
  *ppPrev = p;
  if( (p->wsFlags & WHERE_VIRTUALTABLE)==0 ){
    Index *pIndex = p->u.btree.pIndex;
    if( pIndex && pIndex->tnum==0 ){
      p->u.btree.pIndex = 0;
    }
  }
  return SQLITE4_OK;

  /* Jump here if the insert is a no-op */
whereLoopInsert_noop:
#if WHERETRACE_ENABLED
  if( sqlite4WhereTrace & 0x8 ){
    sqlite4DebugPrintf(pBuilder->pBest ? "ins-skip: " : "ins-noop: ");
    whereLoopPrint(pTemplate, pWInfo->pTabList);
  }
#endif
  return SQLITE4_OK;  
}


/*
** We have so far matched pBuilder->pNew->u.btree.nEq terms of the index pIndex.
** Try to match one more.
*/
static int whereLoopAddBtreeIndex(
  WhereLoopBuilder *pBuilder,     /* The WhereLoop factory */
  struct SrcListItem *pSrc,      /* FROM clause term being analyzed */
  Index *pProbe,                  /* An index on pSrc */
  WhereCost nInMul                /* log(Number of iterations due to IN) */
){
  WhereInfo *pWInfo = pBuilder->pWInfo;  /* WHERE analyse context */
  Parse *pParse = pWInfo->pParse;        /* Parsing context */
  sqlite4 *db = pParse->db;       /* Database connection malloc context */
  WhereLoop *pNew;                /* Template WhereLoop under construction */
  WhereTerm *pTerm;               /* A WhereTerm under consideration */
  int opMask;                     /* Valid operators for constraints */
  WhereScan scan;                 /* Iterator for WHERE terms */
  Bitmask saved_prereq;           /* Original value of pNew->prereq */
  u16 saved_nLTerm;               /* Original value of pNew->nLTerm */
  int saved_nEq;                  /* Original value of pNew->u.btree.nEq */
  u32 saved_wsFlags;              /* Original value of pNew->wsFlags */
  WhereCost saved_nOut;           /* Original value of pNew->nOut */
  int iCol;                       /* Index of the column in the table */
  int rc = SQLITE4_OK;             /* Return code */
  WhereCost nRowEst;              /* Estimated index selectivity */
  WhereCost rLogSize;             /* Logarithm of table size */
  WhereTerm *pTop = 0, *pBtm = 0; /* Top and bottom range constraints */

  assert( pProbe->eIndexType==SQLITE4_INDEX_USER
       || pProbe->eIndexType==SQLITE4_INDEX_UNIQUE
       || pProbe->eIndexType==SQLITE4_INDEX_PRIMARYKEY
  );

  pNew = pBuilder->pNew;
  if( db->mallocFailed ) return SQLITE4_NOMEM;

  assert( (pNew->wsFlags & WHERE_VIRTUALTABLE)==0 );
  assert( (pNew->wsFlags & WHERE_TOP_LIMIT)==0 );
  if( pNew->wsFlags & WHERE_BTM_LIMIT ){
    opMask = WO_LT|WO_LE;
  }else if( pProbe->tnum<=0 || (pSrc->jointype & JT_LEFT)!=0 ){
    opMask = WO_EQ|WO_IN|WO_GT|WO_GE|WO_LT|WO_LE;
  }else{
    opMask = WO_EQ|WO_IN|WO_ISNULL|WO_GT|WO_GE|WO_LT|WO_LE;
  }
  if( pProbe->bUnordered ) opMask &= ~(WO_GT|WO_GE|WO_LT|WO_LE);

  if( pNew->u.btree.nEq < pProbe->nColumn ){
    iCol = pProbe->aiColumn[pNew->u.btree.nEq];
    nRowEst = whereCost(pProbe->aiRowEst[pNew->u.btree.nEq+1]);
    if( nRowEst==0 && pProbe->onError==OE_None ) nRowEst = 1;
  }else if( pProbe->eIndexType!=SQLITE4_INDEX_PRIMARYKEY ){
    Index *pPk;
    pPk = sqlite4FindPrimaryKey(pProbe->pTable, 0);
    iCol = idxColumnNumber(pProbe, pPk, pNew->u.btree.nEq);
    nRowEst = 0;
  }else{
    return SQLITE4_OK;
  }
  assert( iCol>=-1 );
  pTerm = whereScanInit(&scan, pBuilder->pWC, pSrc->iCursor, iCol,
                        opMask, pProbe);
  saved_nEq = pNew->u.btree.nEq;
  saved_nLTerm = pNew->nLTerm;
  saved_wsFlags = pNew->wsFlags;
  saved_prereq = pNew->prereq;
  saved_nOut = pNew->nOut;
  pNew->rSetup = 0;
  rLogSize = estLog(whereCost(pProbe->aiRowEst[0]));
  for(; rc==SQLITE4_OK && pTerm!=0; pTerm = whereScanNext(&scan)){
    int nIn = 0;
    if( pTerm->prereqRight & pNew->maskSelf ) continue;
#ifdef SQLITE4_ENABLE_STAT3
    if( (pTerm->wtFlags & TERM_VNULL)!=0 && pSrc->pTab->aCol[iCol].notNull ){
      continue; /* skip IS NOT NULL constraints on a NOT NULL column */
    }
#endif
    pNew->wsFlags = saved_wsFlags;
    pNew->u.btree.nEq = saved_nEq;
    pNew->nLTerm = saved_nLTerm;
    if( whereLoopResize(db, pNew, pNew->nLTerm+1) ) break; /* OOM */
    pNew->aLTerm[pNew->nLTerm++] = pTerm;
    pNew->prereq = (saved_prereq | pTerm->prereqRight) & ~pNew->maskSelf;
    pNew->rRun = rLogSize; /* Baseline cost is log2(N).  Adjustments below */
    if( pTerm->eOperator & WO_IN ){
      Expr *pExpr = pTerm->pExpr;
      pNew->wsFlags |= WHERE_COLUMN_IN;
      if( ExprHasProperty(pExpr, EP_xIsSelect) ){
        /* "x IN (SELECT ...)":  TUNING: the SELECT returns 25 rows */
        nIn = 46;  assert( 46==whereCost(25) );
      }else if( ALWAYS(pExpr->x.pList && pExpr->x.pList->nExpr) ){
        /* "x IN (value, value, ...)" */
        nIn = whereCost(pExpr->x.pList->nExpr);
      }
      pNew->rRun += nIn;
      pNew->u.btree.nEq++;
      pNew->nOut = nRowEst + nInMul + nIn;
    }else if( pTerm->eOperator & (WO_EQ) ){
      assert( (pNew->wsFlags & (WHERE_COLUMN_NULL|WHERE_COLUMN_IN))!=0
                  || nInMul==0 );
      pNew->wsFlags |= WHERE_COLUMN_EQ;
      if( iCol<0  
       || (pProbe->onError!=OE_None && nInMul==0
           && pNew->u.btree.nEq==pProbe->nColumn-1)
      ){
        assert( (pNew->wsFlags & WHERE_COLUMN_IN)==0 || iCol<0 );
        pNew->wsFlags |= WHERE_ONEROW;
      }
      pNew->u.btree.nEq++;
      pNew->nOut = nRowEst + nInMul;
    }else if( pTerm->eOperator & (WO_ISNULL) ){
      pNew->wsFlags |= WHERE_COLUMN_NULL;
      pNew->u.btree.nEq++;
      /* TUNING: IS NULL selects 2 rows */
      nIn = 10;  assert( 10==whereCost(2) );
      pNew->nOut = nRowEst + nInMul + nIn;
    }else if( pTerm->eOperator & (WO_GT|WO_GE) ){
      testcase( pTerm->eOperator & WO_GT );
      testcase( pTerm->eOperator & WO_GE );
      pNew->wsFlags |= WHERE_COLUMN_RANGE|WHERE_BTM_LIMIT;
      pBtm = pTerm;
      pTop = 0;
    }else{
      assert( pTerm->eOperator & (WO_LT|WO_LE) );
      testcase( pTerm->eOperator & WO_LT );
      testcase( pTerm->eOperator & WO_LE );
      pNew->wsFlags |= WHERE_COLUMN_RANGE|WHERE_TOP_LIMIT;
      pTop = pTerm;
      pBtm = (pNew->wsFlags & WHERE_BTM_LIMIT)!=0 ?
                     pNew->aLTerm[pNew->nLTerm-2] : 0;
    }
    if( pNew->wsFlags & WHERE_COLUMN_RANGE ){
      /* Adjust nOut and rRun for STAT3 range values */
      WhereCost rDiv;
      whereRangeScanEst(pParse, pProbe, pNew->u.btree.nEq,
                        pBtm, pTop, &rDiv);
      pNew->nOut = saved_nOut>rDiv+10 ? saved_nOut - rDiv : 10;
    }
#ifdef SQLITE4_ENABLE_STAT3
    if( pNew->u.btree.nEq==1 && pProbe->nSample
     &&  OptimizationEnabled(db, SQLITE4_Stat3) ){
      tRowcnt nOut = 0;
      if( (pTerm->eOperator & (WO_EQ|WO_ISNULL))!=0 ){
        testcase( pTerm->eOperator & WO_EQ );
        testcase( pTerm->eOperator & WO_ISNULL );
        rc = whereEqualScanEst(pParse, pProbe, pTerm->pExpr->pRight, &nOut);
      }else if( (pTerm->eOperator & WO_IN)
             &&  !ExprHasProperty(pTerm->pExpr, EP_xIsSelect)  ){
        rc = whereInScanEst(pParse, pProbe, pTerm->pExpr->x.pList, &nOut);
      }
      if( rc==SQLITE4_OK ) pNew->nOut = whereCost(nOut);
    }
#endif
    if( (pNew->wsFlags & (WHERE_IDX_ONLY|WHERE_IPK))==0 ){
      /* Each row involves a step of the index, then a binary search of
      ** the main table */
      pNew->rRun =  whereCostAdd(pNew->rRun, rLogSize>27 ? rLogSize-17 : 10);
    }
    /* Step cost for each output row */
    pNew->rRun = whereCostAdd(pNew->rRun, pNew->nOut);
    /* TBD: Adjust nOut for additional constraints */
    rc = whereLoopInsert(pBuilder, pNew);
    if( (pNew->wsFlags & WHERE_TOP_LIMIT)==0
     && pNew->u.btree.nEq<(pProbe->nColumn + (pProbe->zName!=0))
    ){
      whereLoopAddBtreeIndex(pBuilder, pSrc, pProbe, nInMul+nIn);
    }
  }
  pNew->prereq = saved_prereq;
  pNew->u.btree.nEq = saved_nEq;
  pNew->wsFlags = saved_wsFlags;
  pNew->nOut = saved_nOut;
  pNew->nLTerm = saved_nLTerm;
  return rc;
}

/*
** Return True if it is possible that pIndex might be useful in
** implementing the ORDER BY clause in pBuilder.
**
** Return False if pBuilder does not contain an ORDER BY clause or
** if there is no way for pIndex to be useful in implementing that
** ORDER BY clause.
*/
static int indexMightHelpWithOrderBy(
  WhereLoopBuilder *pBuilder,
  Index *pIndex,
  int iCursor
){
  ExprList *pOB;
  int ii, jj;

  if( pIndex->bUnordered ) return 0;
  if( (pOB = pBuilder->pWInfo->pOrderBy)==0 ) return 0;
  for(ii=0; ii<pOB->nExpr; ii++){
    Expr *pExpr = sqlite4ExprSkipCollate(pOB->a[ii].pExpr);
    if( pExpr->op!=TK_COLUMN ) return 0;
    if( pExpr->iTable==iCursor ){
      for(jj=0; jj<pIndex->nColumn; jj++){
        if( pExpr->iColumn==pIndex->aiColumn[jj] ) return 1;
      }
    }
  }
  return 0;
}

/*
** Return a bitmask where 1s indicate that the corresponding column of
** the table is used by an index.  Only the first 63 columns are considered.
*/
static Bitmask columnsInIndex(Index *pIdx){
  Bitmask m = 0;
  int j;
  for(j=pIdx->nColumn-1; j>=0; j--){
    int x = pIdx->aiColumn[j];
    testcase( x==BMS-1 );
    testcase( x==BMS-2 );
    if( x<BMS-1 ) m |= MASKBIT(x);
  }
  return m;
}


/*
** Add all WhereLoop objects for a single table of the join where the table
** is idenfied by pBuilder->pNew->iTab.  That table is guaranteed to be
** a b-tree table, not a virtual table.
*/
static int whereLoopAddBtree(
  WhereLoopBuilder *pBuilder, /* WHERE clause information */
  Bitmask mExtra              /* Extra prerequesites for using this table */
){
  WhereInfo *pWInfo;          /* WHERE analysis context */
  Index *pProbe;              /* An index we are evaluating */
  Index *pPk;                 /* Primary key index for table pSrc */
  tRowcnt aiRowEstPk[2];      /* The aiRowEst[] value for the sPk index */
  int aiColumnPk = -1;        /* The aColumn[] value for the sPk index */
  SrcList *pTabList;          /* The FROM clause */
  struct SrcListItem *pSrc;   /* The FROM clause btree term to add */
  WhereLoop *pNew;            /* Template WhereLoop object */
  int rc = SQLITE4_OK;        /* Return code */
  int iSortIdx = 1;           /* Index number */
  int b;                      /* A boolean value */
  WhereCost rSize;            /* number of rows in the table */
  WhereCost rLogSize;         /* Logarithm of the number of rows in the table */
  
  pNew = pBuilder->pNew;
  pWInfo = pBuilder->pWInfo;
  pTabList = pWInfo->pTabList;
  pSrc = pTabList->a + pNew->iTab;
  assert( !IsVirtual(pSrc->pTab) );
  pPk = sqlite4FindPrimaryKey(pSrc->pTab, 0);

  if( pSrc->pIndex ){
    /* An INDEXED BY clause specifies a particular index to use */
    pProbe = pSrc->pIndex;
  }else if( pSrc->notIndexed ){
    /* A NOT INDEXED clause means use the PK index */
    pProbe = pPk;
  }else{
    /* Otherwise, consider all indexes */
    pProbe = pSrc->pTab->pIndex;
  }

  rSize = whereCost(pSrc->pTab->nRowEst);
  rLogSize = estLog(rSize);

#ifndef SQLITE4_OMIT_AUTOMATIC_INDEX
  /* Automatic indexes */
  if( !pBuilder->pBest
   && (pWInfo->pParse->db->flags & SQLITE4_AutoIndex)!=0
   && pSrc->pIndex==0
#if 0
   && !pSrc->viaCoroutine
#endif
   && !pSrc->notIndexed
   && !pSrc->isCorrelated
  ){
    /* Generate auto-index WhereLoops */
    WhereClause *pWC = pBuilder->pWC;
    WhereTerm *pTerm;
    WhereTerm *pWCEnd = pWC->a + pWC->nTerm;
    for(pTerm=pWC->a; rc==SQLITE4_OK && pTerm<pWCEnd; pTerm++){
      if( pTerm->prereqRight & pNew->maskSelf ) continue;
      if( termCanDriveIndex(pTerm, pSrc, 0) ){
        pNew->u.btree.nEq = 1;
        pNew->u.btree.pIndex = 0;
        pNew->nLTerm = 1;
        pNew->aLTerm[0] = pTerm;
        /* TUNING: One-time cost for computing the automatic index is
        ** approximately 7*N*log2(N) where N is the number of rows in
        ** the table being indexed. */
        pNew->rSetup = rLogSize + rSize + 28;  assert( 28==whereCost(7) );
        /* TUNING: Each index lookup yields 20 rows in the table.  This
        ** is more than the usual guess of 10 rows, since we have no way
        ** of knowning how selective the index will ultimately be.  It would
        ** not be unreasonable to make this value much larger. */
        pNew->nOut = 43;  assert( 43==whereCost(20) );
        pNew->rRun = whereCostAdd(rLogSize,pNew->nOut);
        pNew->wsFlags = WHERE_AUTO_INDEX;
        pNew->prereq = mExtra | pTerm->prereqRight;
        rc = whereLoopInsert(pBuilder, pNew);
      }
    }
  }
#endif /* ifndef SQLITE4_OMIT_AUTOMATIC_INDEX */

  /* If this table has no primary key, then it is either a materialized
  ** view or ephemeral table. Either way, add a WhereLoop for a full-scan 
  ** of it.  */
  if( pPk==0 ){
    assert( pSrc->pTab->pSelect || (pSrc->pTab->tabFlags & TF_Ephemeral) );
    pNew->u.btree.nEq = 0;
    pNew->nLTerm = 0;
    pNew->iSortIdx = 0;
    pNew->rSetup = 0;
    pNew->prereq = mExtra;
    pNew->nOut = rSize;
    pNew->u.btree.pIndex = 0;
    pNew->wsFlags = 0;
    pNew->rRun = whereCostAdd(rSize,rLogSize) + 16;
    rc = whereLoopInsert(pBuilder, pNew);
  }

  /* Loop through the set of indices being considered. */
  for(; rc==SQLITE4_OK && pProbe; pProbe=pProbe->pNext, iSortIdx++){

    if( pProbe->eIndexType==SQLITE4_INDEX_FTS5 ) continue;
    assert( pProbe->tnum>0 );

    pNew->u.btree.nEq = 0;
    pNew->nLTerm = 0;
    pNew->rSetup = 0;
    pNew->prereq = mExtra;
    pNew->nOut = rSize;
    pNew->u.btree.pIndex = pProbe;
    pNew->wsFlags = WHERE_INDEXED;

    b = indexMightHelpWithOrderBy(pBuilder, pProbe, pSrc->iCursor);
    /* The ONEPASS_DESIRED flags never occurs together with ORDER BY */
    assert( (pWInfo->wctrlFlags & WHERE_ONEPASS_DESIRED)==0 || b==0 );
    pNew->iSortIdx = b ? iSortIdx : 0;

    if( pProbe==pPk || b ){
      /* Add a WhereLoop for full-scan via primary key index. */

      /* TUNING: Cost of full table scan is 3*(N + log2(N)).
      **  +  The extra 3 factor is to encourage the use of indexed lookups
      **     over full scans.  A smaller constant 2 is used for covering
      **     index scans so that a covering index scan will be favored over
      **     a table scan. */
      /* TODO: Fix tuning for src4 as described in comment immediately above. */
      pNew->rRun = whereCostAdd(rSize,rLogSize) + 16;
      rc = whereLoopInsert(pBuilder, pNew);
      if( rc ) break;
    }

    rc = whereLoopAddBtreeIndex(pBuilder, pSrc, pProbe, 0);

    /* If there was an INDEXED BY or NOT INDEXED clause, then only one
    ** index is considered. */
    if( pSrc->pIndex || pSrc->notIndexed ) break;
  }
  return rc;
}

#ifndef SQLITE4_OMIT_VIRTUALTABLE
/*
** Add all WhereLoop objects for a table of the join identified by
** pBuilder->pNew->iTab.  That table is guaranteed to be a virtual table.
*/
static int whereLoopAddVirtual(
  WhereLoopBuilder *pBuilder   /* WHERE clause information */
){
  WhereInfo *pWInfo;           /* WHERE analysis context */
  Parse *pParse;               /* The parsing context */
  WhereClause *pWC;            /* The WHERE clause */
  struct SrcListItem *pSrc;   /* The FROM clause term to search */
  Table *pTab;
  sqlite4 *db;
  sqlite4_index_info *pIdxInfo;
  struct sqlite4_index_constraint *pIdxCons;
  struct sqlite4_index_constraint_usage *pUsage;
  WhereTerm *pTerm;
  int i, j;
  int iTerm, mxTerm;
  int nConstraint;
  int seenIn = 0;              /* True if an IN operator is seen */
  int seenVar = 0;             /* True if a non-constant constraint is seen */
  int iPhase;                  /* 0: const w/o IN, 1: const, 2: no IN,  2: IN */
  WhereLoop *pNew;
  int rc = SQLITE4_OK;

  pWInfo = pBuilder->pWInfo;
  pParse = pWInfo->pParse;
  db = pParse->db;
  pWC = pBuilder->pWC;
  pNew = pBuilder->pNew;
  pSrc = &pWInfo->pTabList->a[pNew->iTab];
  pTab = pSrc->pTab;
  assert( IsVirtual(pTab) );
  pIdxInfo = allocateIndexInfo(pParse, pWC, pSrc, pBuilder->pOrderBy);
  if( pIdxInfo==0 ) return SQLITE4_NOMEM;
  pNew->prereq = 0;
  pNew->rSetup = 0;
  pNew->wsFlags = WHERE_VIRTUALTABLE;
  pNew->nLTerm = 0;
  pNew->u.vtab.needFree = 0;
  pUsage = pIdxInfo->aConstraintUsage;
  nConstraint = pIdxInfo->nConstraint;
  if( whereLoopResize(db, pNew, nConstraint) ){
    sqlite4DbFree(db, pIdxInfo);
    return SQLITE4_NOMEM;
  }

  for(iPhase=0; iPhase<=3; iPhase++){
    if( !seenIn && (iPhase&1)!=0 ){
      iPhase++;
      if( iPhase>3 ) break;
    }
    if( !seenVar && iPhase>1 ) break;
    pIdxCons = *(struct sqlite4_index_constraint**)&pIdxInfo->aConstraint;
    for(i=0; i<pIdxInfo->nConstraint; i++, pIdxCons++){
      j = pIdxCons->iTermOffset;
      pTerm = &pWC->a[j];
      switch( iPhase ){
        case 0:    /* Constants without IN operator */
          pIdxCons->usable = 0;
          if( (pTerm->eOperator & WO_IN)!=0 ){
            seenIn = 1;
          }
          if( pTerm->prereqRight!=0 ){
            seenVar = 1;
          }else if( (pTerm->eOperator & WO_IN)==0 ){
            pIdxCons->usable = 1;
          }
          break;
        case 1:    /* Constants with IN operators */
          assert( seenIn );
          pIdxCons->usable = (pTerm->prereqRight==0);
          break;
        case 2:    /* Variables without IN */
          assert( seenVar );
          pIdxCons->usable = (pTerm->eOperator & WO_IN)==0;
          break;
        default:   /* Variables with IN */
          assert( seenVar && seenIn );
          pIdxCons->usable = 1;
          break;
      }
    }
    memset(pUsage, 0, sizeof(pUsage[0])*pIdxInfo->nConstraint);
    if( pIdxInfo->needToFreeIdxStr ) sqlite4_free(pIdxInfo->idxStr);
    pIdxInfo->idxStr = 0;
    pIdxInfo->idxNum = 0;
    pIdxInfo->needToFreeIdxStr = 0;
    pIdxInfo->orderByConsumed = 0;
    pIdxInfo->estimatedCost = SQLITE4_BIG_DBL / (double)2;
    rc = vtabBestIndex(pParse, pTab, pIdxInfo);
    if( rc ) goto whereLoopAddVtab_exit;
    pIdxCons = *(struct sqlite4_index_constraint**)&pIdxInfo->aConstraint;
    pNew->prereq = 0;
    mxTerm = -1;
    assert( pNew->nLSlot>=nConstraint );
    for(i=0; i<nConstraint; i++) pNew->aLTerm[i] = 0;
    pNew->u.vtab.omitMask = 0;
    for(i=0; i<nConstraint; i++, pIdxCons++){
      if( (iTerm = pUsage[i].argvIndex - 1)>=0 ){
        j = pIdxCons->iTermOffset;
        if( iTerm>=nConstraint
         || j<0
         || j>=pWC->nTerm
         || pNew->aLTerm[iTerm]!=0
        ){
          rc = SQLITE4_ERROR;
          sqlite4ErrorMsg(pParse, "%s.xBestIndex() malfunction", pTab->zName);
          goto whereLoopAddVtab_exit;
        }
        testcase( iTerm==nConstraint-1 );
        testcase( j==0 );
        testcase( j==pWC->nTerm-1 );
        pTerm = &pWC->a[j];
        pNew->prereq |= pTerm->prereqRight;
        assert( iTerm<pNew->nLSlot );
        pNew->aLTerm[iTerm] = pTerm;
        if( iTerm>mxTerm ) mxTerm = iTerm;
        testcase( iTerm==15 );
        testcase( iTerm==16 );
        if( iTerm<16 && pUsage[i].omit ) pNew->u.vtab.omitMask |= 1<<iTerm;
        if( (pTerm->eOperator & WO_IN)!=0 ){
          if( pUsage[i].omit==0 ){
            /* Do not attempt to use an IN constraint if the virtual table
            ** says that the equivalent EQ constraint cannot be safely omitted.
            ** If we do attempt to use such a constraint, some rows might be
            ** repeated in the output. */
            break;
          }
          /* A virtual table that is constrained by an IN clause may not
          ** consume the ORDER BY clause because (1) the order of IN terms
          ** is not necessarily related to the order of output terms and
          ** (2) Multiple outputs from a single IN value will not merge
          ** together.  */
          pIdxInfo->orderByConsumed = 0;
        }
      }
    }
    if( i>=nConstraint ){
      pNew->nLTerm = mxTerm+1;
      assert( pNew->nLTerm<=pNew->nLSlot );
      pNew->u.vtab.idxNum = pIdxInfo->idxNum;
      pNew->u.vtab.needFree = pIdxInfo->needToFreeIdxStr;
      pIdxInfo->needToFreeIdxStr = 0;
      pNew->u.vtab.idxStr = pIdxInfo->idxStr;
      pNew->u.vtab.isOrdered = (u8)((pIdxInfo->nOrderBy!=0)
                                     && pIdxInfo->orderByConsumed);
      pNew->rSetup = 0;
      pNew->rRun = whereCostFromDouble(pIdxInfo->estimatedCost);
      /* TUNING: Every virtual table query returns 25 rows */
      pNew->nOut = 46;  assert( 46==whereCost(25) );
      whereLoopInsert(pBuilder, pNew);
      if( pNew->u.vtab.needFree ){
        sqlite4_free(pNew->u.vtab.idxStr);
        pNew->u.vtab.needFree = 0;
      }
    }
  }  

whereLoopAddVtab_exit:
  if( pIdxInfo->needToFreeIdxStr ) sqlite4_free(pIdxInfo->idxStr);
  sqlite4DbFree(db, pIdxInfo);
  return rc;
}
#endif /* SQLITE4_OMIT_VIRTUALTABLE */

/*
** Add WhereLoop entries to handle OR terms.  This works for either
** btrees or virtual tables.
*/
static int whereLoopAddOr(WhereLoopBuilder *pBuilder, Bitmask mExtra){
  WhereInfo *pWInfo = pBuilder->pWInfo;
  WhereClause *pWC;
  WhereLoop *pNew;
  WhereTerm *pTerm, *pWCEnd;
  int rc = SQLITE4_OK;
  int iCur;
  WhereClause tempWC;
  WhereLoopBuilder sSubBuild;
  WhereLoop sBest;
  struct SrcListItem *pItem;
  
  pWC = pBuilder->pWC;
  if( pWInfo->wctrlFlags & WHERE_AND_ONLY ) return SQLITE4_OK;
  pWCEnd = pWC->a + pWC->nTerm;
  pNew = pBuilder->pNew;

  for(pTerm=pWC->a; pTerm<pWCEnd && rc==SQLITE4_OK; pTerm++){
    if( (pTerm->eOperator & WO_OR)!=0
     && (pTerm->u.pOrInfo->indexable & pNew->maskSelf)!=0 
    ){
      WhereClause * const pOrWC = &pTerm->u.pOrInfo->wc;
      WhereTerm * const pOrWCEnd = &pOrWC->a[pOrWC->nTerm];
      WhereTerm *pOrTerm;
      WhereCost rTotal = 0;
      WhereCost nRow = 0;
      Bitmask prereq = mExtra;
    
      whereLoopInit(&sBest);
      pItem = pWInfo->pTabList->a + pNew->iTab;
      iCur = pItem->iCursor;
      sSubBuild = *pBuilder;
      sSubBuild.pOrderBy = 0;
      sSubBuild.pBest = &sBest;

      for(pOrTerm=pOrWC->a; pOrTerm<pOrWCEnd; pOrTerm++){
        if( (pOrTerm->eOperator & WO_AND)!=0 ){
          sSubBuild.pWC = &pOrTerm->u.pAndInfo->wc;
        }else if( pOrTerm->leftCursor==iCur ){
          tempWC.pWInfo = pWC->pWInfo;
          tempWC.pOuter = pWC;
          tempWC.op = TK_AND;
          tempWC.nTerm = 1;
          tempWC.a = pOrTerm;
          sSubBuild.pWC = &tempWC;
        }else{
          continue;
        }
        sBest.maskSelf = 0;
        sBest.rSetup = 0;
        sBest.rRun = 0;
#ifndef SQLITE4_OMIT_VIRTUALTABLE
        if( IsVirtual(pItem->pTab) ){
          rc = whereLoopAddVirtual(&sSubBuild);
        }else
#endif
        {
          rc = whereLoopAddBtree(&sSubBuild, mExtra);
        }
        /* sBest.maskSelf is always zero if an error occurs */
        assert( rc==SQLITE4_OK || sBest.maskSelf==0 );
        if( sBest.maskSelf==0 ) break;
        assert( sBest.rSetup==0 );
        rTotal = whereCostAdd(rTotal, sBest.rRun);
        nRow = whereCostAdd(nRow, sBest.nOut);
        prereq |= sBest.prereq;
      }
      assert( pNew->nLSlot>=1 );
      if( sBest.maskSelf ){
        pNew->nLTerm = 1;
        pNew->aLTerm[0] = pTerm;
        pNew->wsFlags = WHERE_MULTI_OR;
        pNew->rSetup = 0;
        /* TUNING: Multiple by 3.5 for the secondary table lookup */
        pNew->rRun = rTotal + 18; assert( 18==whereCost(7)-whereCost(2) );
        pNew->nOut = nRow;
        pNew->prereq = prereq;
        memset(&pNew->u, 0, sizeof(pNew->u));
        rc = whereLoopInsert(pBuilder, pNew);
      }
      whereLoopClear(pWInfo->pParse->db, &sBest);
    }
  }
  return rc;
}

/*
** Add all WhereLoop objects for all tables 
*/
static int whereLoopAddAll(WhereLoopBuilder *pBuilder){
  WhereInfo *pWInfo = pBuilder->pWInfo;
  Bitmask mExtra = 0;
  Bitmask mPrior = 0;
  int iTab;
  SrcList *pTabList = pWInfo->pTabList;
  struct SrcListItem *pItem;
  sqlite4 *db = pWInfo->pParse->db;
  int nTabList = pWInfo->nLevel;
  int rc = SQLITE4_OK;
  u8 priorJoinType = 0;
  WhereLoop *pNew;

  /* Loop over the tables in the join, from left to right */
  pNew = pBuilder->pNew;
  whereLoopInit(pNew);
  for(iTab=0, pItem=pTabList->a; iTab<nTabList; iTab++, pItem++){
    pNew->iTab = iTab;
    pNew->maskSelf = getMask(&pWInfo->sMaskSet, pItem->iCursor);
    if( ((pItem->jointype|priorJoinType) & (JT_LEFT|JT_CROSS))!=0 ){
      mExtra = mPrior;
    }
    priorJoinType = pItem->jointype;
#ifndef SQLITE4_OMIT_VIRTUALTABLE
    if( IsVirtual(pItem->pTab) ){
      rc = whereLoopAddVirtual(pBuilder);
    }else
#endif
    {
      rc = whereLoopAddBtree(pBuilder, mExtra);
    }
    if( rc==SQLITE4_OK ){
      rc = whereLoopAddOr(pBuilder, mExtra);
    }
    mPrior |= pNew->maskSelf;
    if( rc || db->mallocFailed ) break;
  }
  whereLoopClear(db, pNew);
  return rc;
}

/*
** Examine a WherePath (with the addition of the extra WhereLoop of the 5th
** parameters) to see if it outputs rows in the requested ORDER BY
** (or GROUP BY) without requiring a separate sort operation.  Return:
** 
**    0:  ORDER BY is not satisfied.  Sorting required
**    1:  ORDER BY is satisfied.      Omit sorting
**   -1:  Unknown at this time
**
** Note that processing for WHERE_GROUPBY and WHERE_DISTINCTBY is not as
** strict.  With GROUP BY and DISTINCT the only requirement is that
** equivalent rows appear immediately adjacent to one another.  GROUP BY
** and DISTINT do not require rows to appear in any particular order as long
** as equivelent rows are grouped together.  Thus for GROUP BY and DISTINCT
** the pOrderBy terms can be matched in any order.  With ORDER BY, the 
** pOrderBy terms must be matched in strict left-to-right order.
*/
static int wherePathSatisfiesOrderBy(
  WhereInfo *pWInfo,    /* The WHERE clause */
  ExprList *pOrderBy,   /* ORDER BY or GROUP BY or DISTINCT clause to check */
  WherePath *pPath,     /* The WherePath to check */
  u16 wctrlFlags,       /* Might contain WHERE_GROUPBY or WHERE_DISTINCTBY */
  u16 nLoop,            /* Number of entries in pPath->aLoop[] */
  WhereLoop *pLast,     /* Add this WhereLoop to the end of pPath->aLoop[] */
  Bitmask *pRevMask     /* OUT: Mask of WhereLoops to run in reverse order */
){
  u8 revSet;            /* True if rev is known */
  u8 rev;               /* Composite sort order */
  u8 revIdx;            /* Index sort order */
  u8 isOrderDistinct;   /* All prior WhereLoops are order-distinct */
  u8 isMatch;           /* iColumn matches a term of the ORDER BY clause */
  u16 nColumn;          /* Number of columns in pIndex */
  u16 nOrderBy;         /* Number terms in the ORDER BY clause */
  int iLoop;            /* Index of WhereLoop in pPath being processed */
  int i, j;             /* Loop counters */
  int iCur;             /* Cursor number for current WhereLoop */
  int iColumn;          /* A column number within table iCur */
  WhereLoop *pLoop = 0; /* Current WhereLoop being processed. */
  WhereTerm *pTerm;     /* A single term of the WHERE clause */
  Expr *pOBExpr;        /* An expression from the ORDER BY clause */
  CollSeq *pColl;       /* COLLATE function from an ORDER BY clause term */
  Index *pIndex;        /* The index associated with pLoop */
  sqlite4 *db = pWInfo->pParse->db;  /* Database connection */
  Bitmask obSat = 0;    /* Mask of ORDER BY terms satisfied so far */
  Bitmask obDone;       /* Mask of all ORDER BY terms */
  Bitmask orderDistinctMask;  /* Mask of all well-ordered loops */
  Bitmask ready;              /* Mask of inner loops */

  /*
  ** We say the WhereLoop is "one-row" if it generates no more than one
  ** row of output.  A WhereLoop is one-row if all of the following are true:
  **  (a) All index columns match with WHERE_COLUMN_EQ.
  **  (b) The index is unique
  ** Any WhereLoop with an WHERE_COLUMN_EQ constraint on the rowid is one-row.
  ** Every one-row WhereLoop will have the WHERE_ONEROW bit set in wsFlags.
  **
  ** We say the WhereLoop is "order-distinct" if the set of columns from
  ** that WhereLoop that are in the ORDER BY clause are different for every
  ** row of the WhereLoop.  Every one-row WhereLoop is automatically
  ** order-distinct.   A WhereLoop that has no columns in the ORDER BY clause
  ** is not order-distinct. To be order-distinct is not quite the same as being
  ** UNIQUE since a UNIQUE column or index can have multiple rows that 
  ** are NULL and NULL values are equivalent for the purpose of order-distinct.
  ** To be order-distinct, the columns must be UNIQUE and NOT NULL.
  **
  ** The rowid for a table is always UNIQUE and NOT NULL so whenever the
  ** rowid appears in the ORDER BY clause, the corresponding WhereLoop is
  ** automatically order-distinct.
  */

  assert( pOrderBy!=0 );

  /* Sortability of virtual tables is determined by the xBestIndex method
  ** of the virtual table itself */
  if( pLast->wsFlags & WHERE_VIRTUALTABLE ){
    testcase( nLoop>0 );  /* True when outer loops are one-row and match 
                          ** no ORDER BY terms */
    return pLast->u.vtab.isOrdered;
  }
  if( nLoop && OptimizationDisabled(db, SQLITE4_OrderByIdxJoin) ) return 0;

  nOrderBy = pOrderBy->nExpr;
  testcase( nOrderBy==BMS-1 );
  if( nOrderBy>BMS-1 ) return 0;  /* Cannot optimize overly large ORDER BYs */
  isOrderDistinct = 1;
  obDone = MASKBIT(nOrderBy)-1;
  orderDistinctMask = 0;
  ready = 0;
  for(iLoop=0; isOrderDistinct && obSat<obDone && iLoop<=nLoop; iLoop++){
    if( iLoop>0 ) ready |= pLoop->maskSelf;
    pLoop = iLoop<nLoop ? pPath->aLoop[iLoop] : pLast;
    assert( (pLoop->wsFlags & WHERE_VIRTUALTABLE)==0 );
    iCur = pWInfo->pTabList->a[pLoop->iTab].iCursor;

    /* Mark off any ORDER BY term X that is a column in the table of
    ** the current loop for which there is term in the WHERE
    ** clause of the form X IS NULL or X=? that reference only outer
    ** loops.
    */
    for(i=0; i<nOrderBy; i++){
      if( MASKBIT(i) & obSat ) continue;
      pOBExpr = sqlite4ExprSkipCollate(pOrderBy->a[i].pExpr);
      if( pOBExpr->op!=TK_COLUMN ) continue;
      if( pOBExpr->iTable!=iCur ) continue;
      pTerm = findTerm(&pWInfo->sWC, iCur, pOBExpr->iColumn,
                       ~ready, WO_EQ|WO_ISNULL, 0);
      if( pTerm==0 ) continue;
      if( (pTerm->eOperator&WO_EQ)!=0 && pOBExpr->iColumn>=0 ){
        const char *z1, *z2;
        pColl = sqlite4ExprCollSeq(pWInfo->pParse, pOrderBy->a[i].pExpr);
        if( !pColl ) pColl = db->pDfltColl;
        z1 = pColl->zName;
        pColl = sqlite4ExprCollSeq(pWInfo->pParse, pTerm->pExpr);
        if( !pColl ) pColl = db->pDfltColl;
        z2 = pColl->zName;
        if( sqlite4_stricmp(z1, z2)!=0 ) continue;
      }
      obSat |= MASKBIT(i);
    }

    if( (pLoop->wsFlags & WHERE_ONEROW)==0 ){
      Index *pPk = 0;
      if( pLoop->wsFlags & WHERE_IPK ){
        pIndex = 0;
        nColumn = 0;
      }else if( (pIndex = pLoop->u.btree.pIndex)==0 || pIndex->bUnordered ){
        return 0;
      }else{
        isOrderDistinct = pIndex->onError!=OE_None;
        pPk = sqlite4FindPrimaryKey(pIndex->pTable, 0);
        nColumn = idxColumnCount(pIndex, pPk);
      }

      /* Loop through all columns of the index and deal with the ones
      ** that are not constrained by == or IN.
      */
      rev = revSet = 0;
      for(j=0; j<nColumn; j++){
        u8 bOnce;   /* True to run the ORDER BY search loop */

        /* Skip over == and IS NULL terms */
        if( j<pLoop->u.btree.nEq
         && ((i = pLoop->aLTerm[j]->eOperator) & (WO_EQ|WO_ISNULL))!=0
        ){
          if( i & WO_ISNULL ){
            testcase( isOrderDistinct );
            isOrderDistinct = 0;
          }
          continue;  
        }

        /* Get the column number in the table (iColumn) and sort order
        ** (revIdx) for the j-th column of the index.
        */
        if( j<nColumn ){
          /* Normal index columns */
          iColumn = idxColumnNumber(pIndex, pPk, j);
          revIdx = idxColumnSortOrder(pIndex, pPk, j);
        }else{
          /* The ROWID column at the end */
          assert( j==nColumn );
          iColumn = -1;
          revIdx = 0;
        }

        /* An unconstrained column that might be NULL means that this
        ** WhereLoop is not well-ordered 
        */
        if( isOrderDistinct
         && iColumn>=0
         && j>=pLoop->u.btree.nEq
         && pIndex->pTable->aCol[iColumn].notNull==0
        ){
          isOrderDistinct = 0;
        }

        /* Find the ORDER BY term that corresponds to the j-th column
        ** of the index and and mark that ORDER BY term off 
        */
        bOnce = 1;
        isMatch = 0;
        for(i=0; bOnce && i<nOrderBy; i++){
          if( MASKBIT(i) & obSat ) continue;
          pOBExpr = sqlite4ExprSkipCollate(pOrderBy->a[i].pExpr);
          testcase( wctrlFlags & WHERE_GROUPBY );
          testcase( wctrlFlags & WHERE_DISTINCTBY );
          if( (wctrlFlags & (WHERE_GROUPBY|WHERE_DISTINCTBY))==0 ) bOnce = 0;
          if( pOBExpr->op!=TK_COLUMN ) continue;
          if( pOBExpr->iTable!=iCur ) continue;
          if( pOBExpr->iColumn!=iColumn ) continue;
          if( iColumn>=0 ){
            const char *zIdxColl;
            pColl = sqlite4ExprCollSeq(pWInfo->pParse, pOrderBy->a[i].pExpr);
            if( !pColl ) pColl = db->pDfltColl;
            zIdxColl = idxColumnCollation(pIndex, pPk, j);
            if( sqlite4_stricmp(pColl->zName, zIdxColl)!=0 ) continue;
          }
          isMatch = 1;
          break;
        }
        if( isMatch ){
          obSat |= MASKBIT(i);
          if( (pWInfo->wctrlFlags & WHERE_GROUPBY)==0 ){
            /* Make sure the sort order is compatible in an ORDER BY clause.
            ** Sort order is irrelevant for a GROUP BY clause. */
            if( revSet ){
              if( (rev ^ revIdx)!=pOrderBy->a[i].sortOrder ) return 0;
            }else{
              rev = revIdx ^ pOrderBy->a[i].sortOrder;
              if( rev ) *pRevMask |= MASKBIT(iLoop);
              revSet = 1;
            }
          }
        }else{
          /* No match found */
          if( j==0 || j<nColumn ){
            testcase( isOrderDistinct!=0 );
            isOrderDistinct = 0;
          }
          break;
        }
      } /* end Loop over all index columns */

      /* If (j==nColumn), then each column of the index, including any 
      ** appended PK columns, corresponds to either an ORDER BY term or 
      ** equality constraint. Since the PK columns are collectively UNIQUE
      ** and NOT NULL, consider the loop order-distinct.  */
      if( j==nColumn ){
        testcase( isOrderDistinct==0 );
        isOrderDistinct = 1;
      }
    } /* end-if not one-row */

    /* Mark off any other ORDER BY terms that reference pLoop */
    if( isOrderDistinct ){
      orderDistinctMask |= pLoop->maskSelf;
      for(i=0; i<nOrderBy; i++){
        Expr *p;
        if( MASKBIT(i) & obSat ) continue;
        p = pOrderBy->a[i].pExpr;
        if( (exprTableUsage(&pWInfo->sMaskSet, p)&~orderDistinctMask)==0 ){
          obSat |= MASKBIT(i);
        }
      }
    }
  } /* End the loop over all WhereLoops from outer-most down to inner-most */
  if( obSat==obDone ) return 1;
  if( !isOrderDistinct ) return 0;
  return -1;
}

#ifdef WHERETRACE_ENABLED
/* For debugging use only: */
static const char *wherePathName(WherePath *pPath, int nLoop, WhereLoop *pLast){
  static char zName[65];
  int i;
  for(i=0; i<nLoop; i++){ zName[i] = pPath->aLoop[i]->cId; }
  if( pLast ) zName[i++] = pLast->cId;
  zName[i] = 0;
  return zName;
}
#endif


/*
** Given the list of WhereLoop objects at pWInfo->pLoops, this routine
** attempts to find the lowest cost path that visits each WhereLoop
** once.  This path is then loaded into the pWInfo->a[].pWLoop fields.
**
** Assume that the total number of output rows that will need to be sorted
** will be nRowEst (in the 10*log2 representation).  Or, ignore sorting
** costs if nRowEst==0.
**
** Return SQLITE4_OK on success or SQLITE4_NOMEM of a memory allocation
** error occurs.
*/
static int wherePathSolver(WhereInfo *pWInfo, WhereCost nRowEst){
  int mxChoice;             /* Maximum number of simultaneous paths tracked */
  int nLoop;                /* Number of terms in the join */
  Parse *pParse;            /* Parsing context */
  sqlite4 *db;              /* The database connection */
  int iLoop;                /* Loop counter over the terms of the join */
  int ii, jj;               /* Loop counters */
  WhereCost rCost;             /* Cost of a path */
  WhereCost mxCost = 0;        /* Maximum cost of a set of paths */
  WhereCost rSortCost;         /* Cost to do a sort */
  int nTo, nFrom;           /* Number of valid entries in aTo[] and aFrom[] */
  WherePath *aFrom;         /* All nFrom paths at the previous level */
  WherePath *aTo;           /* The nTo best paths at the current level */
  WherePath *pFrom;         /* An element of aFrom[] that we are working on */
  WherePath *pTo;           /* An element of aTo[] that we are working on */
  WhereLoop *pWLoop;        /* One of the WhereLoop objects */
  WhereLoop **pX;           /* Used to divy up the pSpace memory */
  char *pSpace;             /* Temporary memory used by this routine */

  pParse = pWInfo->pParse;
  db = pParse->db;
  nLoop = pWInfo->nLevel;
  /* TUNING: For simple queries, only the best path is tracked.
  ** For 2-way joins, the 5 best paths are followed.
  ** For joins of 3 or more tables, track the 10 best paths */
  mxChoice = (nLoop==1) ? 1 : (nLoop==2 ? 5 : 10);
  assert( nLoop<=pWInfo->pTabList->nSrc );
  WHERETRACE(0x002, ("---- begin solver\n"));

  /* Allocate and initialize space for aTo and aFrom */
  ii = (sizeof(WherePath)+sizeof(WhereLoop*)*nLoop)*mxChoice*2;
  pSpace = sqlite4DbMallocRaw(db, ii);
  if( pSpace==0 ) return SQLITE4_NOMEM;
  aTo = (WherePath*)pSpace;
  aFrom = aTo+mxChoice;
  memset(aFrom, 0, sizeof(aFrom[0]));
  pX = (WhereLoop**)(aFrom+mxChoice);
  for(ii=mxChoice*2, pFrom=aTo; ii>0; ii--, pFrom++, pX += nLoop){
    pFrom->aLoop = pX;
  }

  /* Seed the search with a single WherePath containing zero WhereLoops.
  **
  ** TUNING: Do not let the number of iterations go above 25.  If the cost
  ** of computing an automatic index is not paid back within the first 25
  ** rows, then do not use the automatic index. */
  aFrom[0].nRow = MIN(pParse->nQueryLoop, 46);  assert( 46==whereCost(25) );
  nFrom = 1;

  /* Precompute the cost of sorting the final result set, if the caller
  ** to sqlite4WhereBegin() was concerned about sorting */
  rSortCost = 0;
  if( pWInfo->pOrderBy==0 || nRowEst==0 ){
    aFrom[0].isOrderedValid = 1;
  }else{
    /* TUNING: Estimated cost of sorting is N*log2(N) where N is the
    ** number of output rows. */
    rSortCost = nRowEst + estLog(nRowEst);
    WHERETRACE(0x002,("---- sort cost=%-3d\n", rSortCost));
  }

  /* Compute successively longer WherePaths using the previous generation
  ** of WherePaths as the basis for the next.  Keep track of the mxChoice
  ** best paths at each generation */
  for(iLoop=0; iLoop<nLoop; iLoop++){
    nTo = 0;
    for(ii=0, pFrom=aFrom; ii<nFrom; ii++, pFrom++){
      for(pWLoop=pWInfo->pLoops; pWLoop; pWLoop=pWLoop->pNextLoop){
        Bitmask maskNew;
        Bitmask revMask = 0;
        u8 isOrderedValid = pFrom->isOrderedValid;
        u8 isOrdered = pFrom->isOrdered;
        if( (pWLoop->prereq & ~pFrom->maskLoop)!=0 ) continue;
        if( (pWLoop->maskSelf & pFrom->maskLoop)!=0 ) continue;
        /* At this point, pWLoop is a candidate to be the next loop. 
        ** Compute its cost */
        rCost = whereCostAdd(pWLoop->rSetup,pWLoop->rRun + pFrom->nRow);
        rCost = whereCostAdd(rCost, pFrom->rCost);
        maskNew = pFrom->maskLoop | pWLoop->maskSelf;
        if( !isOrderedValid ){
          switch( wherePathSatisfiesOrderBy(pWInfo,
                       pWInfo->pOrderBy, pFrom, pWInfo->wctrlFlags,
                       iLoop, pWLoop, &revMask) ){
            case 1:  /* Yes.  pFrom+pWLoop does satisfy the ORDER BY clause */
              isOrdered = 1;
              isOrderedValid = 1;
              break;
            case 0:  /* No.  pFrom+pWLoop will require a separate sort */
              isOrdered = 0;
              isOrderedValid = 1;
              rCost = whereCostAdd(rCost, rSortCost);
              break;
            default: /* Cannot tell yet.  Try again on the next iteration */
              break;
          }
        }else{
          revMask = pFrom->revLoop;
        }
        /* Check to see if pWLoop should be added to the mxChoice best so far */
        for(jj=0, pTo=aTo; jj<nTo; jj++, pTo++){
          if( pTo->maskLoop==maskNew && pTo->isOrderedValid==isOrderedValid ){
            testcase( jj==nTo-1 );
            break;
          }
        }
        if( jj>=nTo ){
          if( nTo>=mxChoice && rCost>=mxCost ){
#ifdef WHERETRACE_ENABLED
            if( sqlite4WhereTrace&0x4 ){
              sqlite4DebugPrintf("Skip   %s cost=%3d order=%c\n",
                  wherePathName(pFrom, iLoop, pWLoop), rCost,
                  isOrderedValid ? (isOrdered ? 'Y' : 'N') : '?');
            }
#endif
            continue;
          }
          /* Add a new Path to the aTo[] set */
          if( nTo<mxChoice ){
            /* Increase the size of the aTo set by one */
            jj = nTo++;
          }else{
            /* New path replaces the prior worst to keep count below mxChoice */
            for(jj=nTo-1; aTo[jj].rCost<mxCost; jj--){ assert(jj>0); }
          }
          pTo = &aTo[jj];
#ifdef WHERETRACE_ENABLED
          if( sqlite4WhereTrace&0x4 ){
            sqlite4DebugPrintf("New    %s cost=%-3d order=%c\n",
                wherePathName(pFrom, iLoop, pWLoop), rCost,
                isOrderedValid ? (isOrdered ? 'Y' : 'N') : '?');
          }
#endif
        }else{
          if( pTo->rCost<=rCost ){
#ifdef WHERETRACE_ENABLED
            if( sqlite4WhereTrace&0x4 ){
              sqlite4DebugPrintf(
                  "Skip   %s cost=%-3d order=%c",
                  wherePathName(pFrom, iLoop, pWLoop), rCost,
                  isOrderedValid ? (isOrdered ? 'Y' : 'N') : '?');
              sqlite4DebugPrintf("   vs %s cost=%-3d order=%c\n",
                  wherePathName(pTo, iLoop+1, 0), pTo->rCost,
                  pTo->isOrderedValid ? (pTo->isOrdered ? 'Y' : 'N') : '?');
            }
#endif
            testcase( pTo->rCost==rCost );
            continue;
          }
          testcase( pTo->rCost==rCost+1 );
          /* A new and better score for a previously created equivalent path */
#ifdef WHERETRACE_ENABLED
          if( sqlite4WhereTrace&0x4 ){
            sqlite4DebugPrintf(
                "Update %s cost=%-3d order=%c",
                wherePathName(pFrom, iLoop, pWLoop), rCost,
                isOrderedValid ? (isOrdered ? 'Y' : 'N') : '?');
            sqlite4DebugPrintf("  was %s cost=%-3d order=%c\n",
                wherePathName(pTo, iLoop+1, 0), pTo->rCost,
                pTo->isOrderedValid ? (pTo->isOrdered ? 'Y' : 'N') : '?');
          }
#endif
        }
        /* pWLoop is a winner.  Add it to the set of best so far */
        pTo->maskLoop = pFrom->maskLoop | pWLoop->maskSelf;
        pTo->revLoop = revMask;
        pTo->nRow = pFrom->nRow + pWLoop->nOut;
        pTo->rCost = rCost;
        pTo->isOrderedValid = isOrderedValid;
        pTo->isOrdered = isOrdered;
        memcpy(pTo->aLoop, pFrom->aLoop, sizeof(WhereLoop*)*iLoop);
        pTo->aLoop[iLoop] = pWLoop;
        if( nTo>=mxChoice ){
          mxCost = aTo[0].rCost;
          for(jj=1, pTo=&aTo[1]; jj<mxChoice; jj++, pTo++){
            if( pTo->rCost>mxCost ) mxCost = pTo->rCost;
          }
        }
      }
    }

#ifdef WHERETRACE_ENABLED
    if( sqlite4WhereTrace>=2 ){
      sqlite4DebugPrintf("---- after round %d ----\n", iLoop);
      for(ii=0, pTo=aTo; ii<nTo; ii++, pTo++){
        sqlite4DebugPrintf(" %s cost=%-3d nrow=%-3d order=%c",
           wherePathName(pTo, iLoop+1, 0), pTo->rCost, pTo->nRow,
           pTo->isOrderedValid ? (pTo->isOrdered ? 'Y' : 'N') : '?');
        if( pTo->isOrderedValid && pTo->isOrdered ){
          sqlite4DebugPrintf(" rev=0x%llx\n", pTo->revLoop);
        }else{
          sqlite4DebugPrintf("\n");
        }
      }
    }
#endif

    /* Swap the roles of aFrom and aTo for the next generation */
    pFrom = aTo;
    aTo = aFrom;
    aFrom = pFrom;
    nFrom = nTo;
  }

  if( nFrom==0 ){
    sqlite4ErrorMsg(pParse, "no query solution");
    sqlite4DbFree(db, pSpace);
    return SQLITE4_ERROR;
  }
  
  /* Find the lowest cost path.  pFrom will be left pointing to that path */
  pFrom = aFrom;
  assert( nFrom==1 );
#if 0 /* The following is needed if nFrom is ever more than 1 */
  for(ii=1; ii<nFrom; ii++){
    if( pFrom->rCost>aFrom[ii].rCost ) pFrom = &aFrom[ii];
  }
#endif
  assert( pWInfo->nLevel==nLoop );
  /* Load the lowest cost path into pWInfo */
  for(iLoop=0; iLoop<nLoop; iLoop++){
    WhereLevel *pLevel = pWInfo->a + iLoop;
    pLevel->pWLoop = pWLoop = pFrom->aLoop[iLoop];
    pLevel->iFrom = pWLoop->iTab;
    pLevel->iTabCur = pWInfo->pTabList->a[pLevel->iFrom].iCursor;
  }
  if( (pWInfo->wctrlFlags & WHERE_WANT_DISTINCT)!=0
   && (pWInfo->wctrlFlags & WHERE_DISTINCTBY)==0
   && pWInfo->eDistinct==WHERE_DISTINCT_NOOP
   && nRowEst
  ){
    Bitmask notUsed;
    int rc = wherePathSatisfiesOrderBy(pWInfo, pWInfo->pResultSet, pFrom,
                 WHERE_DISTINCTBY, nLoop-1, pFrom->aLoop[nLoop-1], &notUsed);
    if( rc==1 ) pWInfo->eDistinct = WHERE_DISTINCT_ORDERED;
  }
  if( pFrom->isOrdered ){
    if( pWInfo->wctrlFlags & WHERE_DISTINCTBY ){
      pWInfo->eDistinct = WHERE_DISTINCT_ORDERED;
    }else{
      pWInfo->bOBSat = 1;
      pWInfo->revMask = pFrom->revLoop;
    }
  }
  pWInfo->nRowOut = pFrom->nRow;

  /* Free temporary memory and return success */
  sqlite4DbFree(db, pSpace);
  return SQLITE4_OK;
}

/*
** Most queries use only a single table (they are not joins) and have
** simple == constraints against indexed fields.  This routine attempts
** to plan those simple cases using much less ceremony than the
** general-purpose query planner, and thereby yield faster sqlite4_prepare()
** times for the common case.
**
** Return non-zero on success, if this query can be handled by this
** no-frills query planner.  Return zero if this query needs the 
** general-purpose query planner.
*/
static int whereShortCut(WhereLoopBuilder *pBuilder){
  WhereInfo *pWInfo;
  struct SrcListItem *pItem;
  WhereClause *pWC;
  WhereTerm *pTerm;
  WhereLoop *pLoop;
  int iCur;
  int j;
  Table *pTab;
  Index *pIdx;

  return 0;
  
  pWInfo = pBuilder->pWInfo;
  if( pWInfo->wctrlFlags & WHERE_FORCE_TABLE ) return 0;
  assert( pWInfo->pTabList->nSrc>=1 );
  pItem = pWInfo->pTabList->a;
  pTab = pItem->pTab;
  if( IsVirtual(pTab) ) return 0;
  if( pItem->zIndex ) return 0;
  iCur = pItem->iCursor;
  pWC = &pWInfo->sWC;
  pLoop = pBuilder->pNew;
  pLoop->wsFlags = 0;
  pTerm = findTerm(pWC, iCur, -1, 0, WO_EQ, 0);
  if( pTerm ){
    assert( 0 );
    pLoop->wsFlags = WHERE_COLUMN_EQ|WHERE_IPK|WHERE_ONEROW;
    pLoop->aLTerm[0] = pTerm;
    pLoop->nLTerm = 1;
    pLoop->u.btree.nEq = 1;
    /* TUNING: Cost of a rowid lookup is 10 */
    pLoop->rRun = 33;  /* 33==whereCost(10) */
  }else{
    for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
      if( pIdx->onError==OE_None ) continue;
      for(j=0; j<pIdx->nColumn; j++){
        pTerm = findTerm(pWC, iCur, pIdx->aiColumn[j], 0, WO_EQ, pIdx);
        if( pTerm==0 ) break;
        whereLoopResize(pWInfo->pParse->db, pLoop, j);
        pLoop->aLTerm[j] = pTerm;
      }
      if( j!=pIdx->nColumn ) continue;
      pLoop->wsFlags = WHERE_COLUMN_EQ|WHERE_ONEROW|WHERE_INDEXED;
      if( (pItem->colUsed & ~columnsInIndex(pIdx))==0 ){
        pLoop->wsFlags |= WHERE_IDX_ONLY;
      }
      pLoop->nLTerm = j;
      pLoop->u.btree.nEq = j;
      pLoop->u.btree.pIndex = pIdx;
      /* TUNING: Cost of a unique index lookup is 15 */
      pLoop->rRun = 39;  /* 39==whereCost(15) */
      break;
    }
  }
  if( pLoop->wsFlags ){
    pLoop->nOut = (WhereCost)1;
    pWInfo->a[0].pWLoop = pLoop;
    pLoop->maskSelf = getMask(&pWInfo->sMaskSet, iCur);
    pWInfo->a[0].iTabCur = iCur;
    pWInfo->nRowOut = 1;
    if( pWInfo->pOrderBy ) pWInfo->bOBSat =  1;
    if( pWInfo->wctrlFlags & WHERE_WANT_DISTINCT ){
      pWInfo->eDistinct = WHERE_DISTINCT_UNIQUE;
    }
#ifdef SQLITE4_DEBUG
    pLoop->cId = '0';
#endif
    return 1;
  }
  return 0;
}

/*
** Generate the beginning of the loop used for WHERE clause processing.
** The return value is a pointer to an opaque structure that contains
** information needed to terminate the loop.  Later, the calling routine
** should invoke sqlite4WhereEnd() with the return value of this function
** in order to complete the WHERE clause processing.
4527
4528
4529
4530
4531
4532
4533
4534
4535
4536
4537
4538
4539
4540
4541
**
** Note that the loops might not be nested in the order in which they
** appear in the FROM clause if a different order is better able to make
** use of indices.  Note also that when the IN operator appears in
** the WHERE clause, it might result in additional nested loops for
** scanning through all values on the right-hand side of the IN.
**
** There are cursors associated with each table.  t1 uses cursor
** number pTabList->a[0].iCursor.  t2 uses the cursor pTabList->a[1].iCursor.
** And so forth.  This routine generates code to open those VDBE cursors
** and sqlite4WhereEnd() generates the code to close them.
**
** The code that sqlite4WhereBegin() generates leaves the cursors named
** in pTabList pointing at their appropriate entries.  The [...] code
** can use OP_Column and OP_Rowid opcodes on these cursors to extract







|







5643
5644
5645
5646
5647
5648
5649
5650
5651
5652
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5655
5656
5657
**
** Note that the loops might not be nested in the order in which they
** appear in the FROM clause if a different order is better able to make
** use of indices.  Note also that when the IN operator appears in
** the WHERE clause, it might result in additional nested loops for
** scanning through all values on the right-hand side of the IN.
**
** There are Btree cursors associated with each table.  t1 uses cursor
** number pTabList->a[0].iCursor.  t2 uses the cursor pTabList->a[1].iCursor.
** And so forth.  This routine generates code to open those VDBE cursors
** and sqlite4WhereEnd() generates the code to close them.
**
** The code that sqlite4WhereBegin() generates leaves the cursors named
** in pTabList pointing at their appropriate entries.  The [...] code
** can use OP_Column and OP_Rowid opcodes on these cursors to extract
4570
4571
4572
4573
4574
4575
4576
4577

4578
4579
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4597
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4603

4604
4605
4606
4607
4608
4609
4610















4611
4612
4613
4614
4615
4616
4617
**        move the row2 cursor to a null row
**        goto start
**      fi
**    end
**
** ORDER BY CLAUSE PROCESSING
**
** *ppOrderBy is a pointer to the ORDER BY clause of a SELECT statement,

** if there is one.  If there is no ORDER BY clause or if this routine
** is called from an UPDATE or DELETE statement, then ppOrderBy is NULL.
**
** If an index can be used so that the natural output order of the table
** scan is correct for the ORDER BY clause, then that index is used and
** *ppOrderBy is set to NULL.  This is an optimization that prevents an
** unnecessary sort of the result set if an index appropriate for the
** ORDER BY clause already exists.
**
** If the where clause loops cannot be arranged to provide the correct
** output order, then the *ppOrderBy is unchanged.
*/
WhereInfo *sqlite4WhereBegin(
  Parse *pParse,        /* The parser context */
  SrcList *pTabList,    /* A list of all tables to be scanned */
  Expr *pWhere,         /* The WHERE clause */
  ExprList **ppOrderBy, /* An ORDER BY clause, or NULL */
  ExprList *pDistinct,  /* The select-list for DISTINCT queries - or NULL */
  u16 wctrlFlags        /* One of the WHERE_* flags defined in sqliteInt.h */

){
  int i;                     /* Loop counter */
  int nByteWInfo;            /* Num. bytes allocated for WhereInfo struct */
  int nTabList;              /* Number of elements in pTabList */
  WhereInfo *pWInfo;         /* Will become the return value of this function */
  Vdbe *v = pParse->pVdbe;   /* The virtual database engine */
  Bitmask notReady;          /* Cursors that are not yet positioned */

  WhereMaskSet *pMaskSet;    /* The expression mask set */
  WhereClause *pWC;               /* Decomposition of the WHERE clause */
  SrcListItem *pTabItem;  /* A single entry from pTabList */
  WhereLevel *pLevel;             /* A single level in the pWInfo list */
  int iFrom;                      /* First unused FROM clause element */
  int andFlags;              /* AND-ed combination of all pWC->a[].wtFlags */
  sqlite4 *db;               /* Database connection */
















  /* The number of tables in the FROM clause is limited by the number of
  ** bits in a Bitmask 
  */
  testcase( pTabList->nSrc==BMS );
  if( pTabList->nSrc>BMS ){
    sqlite4ErrorMsg(pParse, "at most %d tables in a join", BMS);







|
>

|
<
<
<
<
<
<
<
<
<



|

|
|
|
>

<





>

<
<
|
|
|

>
>
>
>
>
>
>
>
>
>
>
>
>
>
>







5686
5687
5688
5689
5690
5691
5692
5693
5694
5695
5696









5697
5698
5699
5700
5701
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5703
5704
5705
5706

5707
5708
5709
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5714
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5737
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5739
**        move the row2 cursor to a null row
**        goto start
**      fi
**    end
**
** ORDER BY CLAUSE PROCESSING
**
** pOrderBy is a pointer to the ORDER BY clause (or the GROUP BY clause
** if the WHERE_GROUPBY flag is set in wctrlFlags) of a SELECT statement
** if there is one.  If there is no ORDER BY clause or if this routine
** is called from an UPDATE or DELETE statement, then pOrderBy is NULL.









*/
WhereInfo *sqlite4WhereBegin(
  Parse *pParse,        /* The parser context */
  SrcList *pTabList,    /* FROM clause: A list of all tables to be scanned */
  Expr *pWhere,         /* The WHERE clause */
  ExprList *pOrderBy,   /* An ORDER BY clause, or NULL */
  ExprList *pResultSet, /* Result set of the query */
  u16 wctrlFlags,       /* One of the WHERE_* flags defined in sqliteInt.h */
  int iIdxCur           /* If WHERE_ONETABLE_ONLY is set, index cursor number */
){

  int nByteWInfo;            /* Num. bytes allocated for WhereInfo struct */
  int nTabList;              /* Number of elements in pTabList */
  WhereInfo *pWInfo;         /* Will become the return value of this function */
  Vdbe *v = pParse->pVdbe;   /* The virtual database engine */
  Bitmask notReady;          /* Cursors that are not yet positioned */
  WhereLoopBuilder sWLB;     /* The WhereLoop builder */
  WhereMaskSet *pMaskSet;    /* The expression mask set */


  WhereLevel *pLevel;        /* A single level in pWInfo->a[] */
  WhereLoop *pLoop;          /* Pointer to a single WhereLoop object */
  int ii;                    /* Loop counter */
  sqlite4 *db;               /* Database connection */
  int rc;                    /* Return code */

  /* src4: In SQLite3, the caller would set this flag. */
  if( pResultSet ) wctrlFlags |= WHERE_WANT_DISTINCT;

  /* Variable initialization */
  db = pParse->db;
  memset(&sWLB, 0, sizeof(sWLB));
  sWLB.pOrderBy = pOrderBy;

  /* Disable the DISTINCT optimization if SQLITE4_DistinctOpt is set via
  ** sqlite4_test_ctrl(SQLITE4_TESTCTRL_OPTIMIZATIONS,...) */
  if( OptimizationDisabled(db, SQLITE4_DistinctOpt) ){
    wctrlFlags &= ~WHERE_WANT_DISTINCT;
  }

  /* The number of tables in the FROM clause is limited by the number of
  ** bits in a Bitmask 
  */
  testcase( pTabList->nSrc==BMS );
  if( pTabList->nSrc>BMS ){
    sqlite4ErrorMsg(pParse, "at most %d tables in a join", BMS);
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4674









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4729



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4785

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4807



4808
4809



4810
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4818
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4821
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4856
4857
4858




4859
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4896






4897
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4901
4902

4903



4904
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4906
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4908
4909

4910
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4917

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4932

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4945
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4947

4948
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4955

4956
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4960
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4963

4964
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4973
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  /* Allocate and initialize the WhereInfo structure that will become the
  ** return value. A single allocation is used to store the WhereInfo
  ** struct, the contents of WhereInfo.a[], the WhereClause structure
  ** and the WhereMaskSet structure. Since WhereClause contains an 8-byte
  ** field (type Bitmask) it must be aligned on an 8-byte boundary on
  ** some architectures. Hence the ROUND8() below.
  */
  db = pParse->db;
  nByteWInfo = ROUND8(sizeof(WhereInfo)+(nTabList-1)*sizeof(WhereLevel));
  pWInfo = sqlite4DbMallocZero(db, 
      nByteWInfo + 
      sizeof(WhereClause) +
      sizeof(WhereMaskSet)
  );
  if( db->mallocFailed ){
    sqlite4DbFree(db, pWInfo);
    pWInfo = 0;
    goto whereBeginError;
  }
  pWInfo->nLevel = nTabList;
  pWInfo->pParse = pParse;
  pWInfo->pTabList = pTabList;


  pWInfo->iBreak = sqlite4VdbeMakeLabel(v);
  pWInfo->pWC = pWC = (WhereClause *)&((u8 *)pWInfo)[nByteWInfo];
  pWInfo->wctrlFlags = wctrlFlags;
  pWInfo->savedNQueryLoop = pParse->nQueryLoop;
  pMaskSet = (WhereMaskSet*)&pWC[1];

  /* Disable the DISTINCT optimization if SQLITE4_DistinctOpt is set via
  ** sqlite4_test_ctrl(SQLITE4_TESTCTRL_OPTIMIZATIONS,...) */


  if( db->flags & SQLITE4_DistinctOpt ) pDistinct = 0;



  /* Split the WHERE clause into separate subexpressions where each
  ** subexpression is separated by an AND operator.
  */
  initMaskSet(pMaskSet);
  whereClauseInit(pWC, pParse, pMaskSet, wctrlFlags);
  sqlite4ExprCodeConstants(pParse, pWhere);
  whereSplit(pWC, pWhere, TK_AND);   /* IMP: R-15842-53296 */

    
  /* Special case: a WHERE clause that is constant.  Evaluate the
  ** expression and either jump over all of the code or fall thru.
  */
  if( pWhere && (nTabList==0 || sqlite4ExprIsConstantNotJoin(pWhere)) ){
    sqlite4ExprIfFalse(pParse, pWhere, pWInfo->iBreak, SQLITE4_JUMPIFNULL);
    pWhere = 0;
  }










  /* Assign a bit from the bitmask to every term in the FROM clause.
  **
  ** When assigning bitmask values to FROM clause cursors, it must be
  ** the case that if X is the bitmask for the N-th FROM clause term then
  ** the bitmask for all FROM clause terms to the left of the N-th term
  ** is (X-1).   An expression from the ON clause of a LEFT JOIN can use
  ** its Expr.iRightJoinTable value to find the bitmask of the right table
  ** of the join.  Subtracting one from the right table bitmask gives a
  ** bitmask for all tables to the left of the join.  Knowing the bitmask
  ** for all tables to the left of a left join is important.  Ticket #3015.
  **
  ** Configure the WhereClause.vmask variable so that bits that correspond
  ** to virtual table cursors are set. This is used to selectively disable 
  ** the OR-to-IN transformation in exprAnalyzeOrTerm(). It is not helpful 
  ** with virtual tables.
  **
  ** Note that bitmasks are created for all pTabList->nSrc tables in
  ** pTabList, not just the first nTabList tables.  nTabList is normally
  ** equal to pTabList->nSrc but might be shortened to 1 if the
  ** WHERE_ONETABLE_ONLY flag is set.
  */
  assert( pWC->vmask==0 && pMaskSet->n==0 );
  for(i=0; i<pTabList->nSrc; i++){
    createMask(pMaskSet, pTabList->a[i].iCursor);
#ifndef SQLITE4_OMIT_VIRTUALTABLE
    if( ALWAYS(pTabList->a[i].pTab) && IsVirtual(pTabList->a[i].pTab) ){
      pWC->vmask |= ((Bitmask)1 << i);
    }
#endif
  }
#ifndef NDEBUG
  {
    Bitmask toTheLeft = 0;
    for(i=0; i<pTabList->nSrc; i++){
      Bitmask m = getMask(pMaskSet, pTabList->a[i].iCursor);
      assert( (m-1)==toTheLeft );
      toTheLeft |= m;
    }
  }
#endif

  /* Analyze all of the subexpressions. */




  exprAnalyzeAll(pTabList, pWC);
  if( db->mallocFailed ){
    goto whereBeginError;
  }

  /* Check if the DISTINCT qualifier, if there is one, is redundant. 
  ** If it is, then set pDistinct to NULL and WhereInfo.eDistinct to
  ** WHERE_DISTINCT_UNIQUE to tell the caller to ignore the DISTINCT.
  */
  if( pDistinct && isDistinctRedundant(pParse, pTabList, pWC, pDistinct) ){
    pDistinct = 0;


    pWInfo->eDistinct = WHERE_DISTINCT_UNIQUE;



  }

  /* Chose the best index to use for each table in the FROM clause.
  **
  ** This loop fills in the following fields:
  **
  **   pWInfo->a[].pIdx      The index to use for this level of the loop.
  **   pWInfo->a[].wsFlags   WHERE_xxx flags associated with pIdx
  **   pWInfo->a[].nEq       The number of == and IN constraints
  **   pWInfo->a[].iFrom     Which term of the FROM clause is being coded
  **   pWInfo->a[].iTabCur   The VDBE cursor for the database table
  **   pWInfo->a[].iIdxCur   The VDBE cursor for the index
  **   pWInfo->a[].pTerm     When wsFlags==WO_OR, the OR-clause term
  **
  ** This loop also figures out the nesting order of tables in the FROM
  ** clause.
  */
  notReady = ~(Bitmask)0;
  andFlags = ~0;
  WHERETRACE(("*** Optimizer Start ***\n"));
  for(i=iFrom=0, pLevel=pWInfo->a; i<nTabList; i++, pLevel++){
    WhereCost bestPlan;         /* Most efficient plan seen so far */

    Index *pIdx;                /* Index for FROM table at pTabItem */
    int j;                      /* For looping over FROM tables */

    int bestJ = -1;             /* The value of j */
    Bitmask m;                  /* Bitmask value for j or bestJ */
    int isOptimal;              /* Iterator for optimal/non-optimal search */
    int nUnconstrained;         /* Number tables without INDEXED BY */
    Bitmask notIndexed;         /* Mask of tables that cannot use an index */



    memset(&bestPlan, 0, sizeof(bestPlan));
    bestPlan.rCost = SQLITE4_BIG_DBL;
    WHERETRACE(("*** Begin search for loop %d ***\n", i));

    /* Loop through the remaining entries in the FROM clause to find the
    ** next nested loop. The loop tests all FROM clause entries
    ** either once or twice. 
    **
    ** The first test is always performed if there are two or more entries
    ** remaining and never performed if there is only one FROM clause entry
    ** to choose from.  The first test looks for an "optimal" scan.  In
    ** this context an optimal scan is one that uses the same strategy
    ** for the given FROM clause entry as would be selected if the entry
    ** were used as the innermost nested loop.  In other words, a table
    ** is chosen such that the cost of running that table cannot be reduced
    ** by waiting for other tables to run first.  This "optimal" test works
    ** by first assuming that the FROM clause is on the inner loop and finding
    ** its query plan, then checking to see if that query plan uses any
    ** other FROM clause terms that are notReady.  If no notReady terms are
    ** used then the "optimal" query plan works.
    **
    ** Note that the WhereCost.nRow parameter for an optimal scan might
    ** not be as small as it would be if the table really were the innermost
    ** join.  The nRow value can be reduced by WHERE clause constraints
    ** that do not use indices.  But this nRow reduction only happens if the
    ** table really is the innermost join.  

    **
    ** The second loop iteration is only performed if no optimal scan
    ** strategies were found by the first iteration. This second iteration
    ** is used to search for the lowest cost scan overall.
    **
    ** Previous versions of SQLite performed only the second iteration -
    ** the next outermost loop was always that with the lowest overall
    ** cost. However, this meant that SQLite could select the wrong plan
    ** for scripts such as the following:
    **   
    **   CREATE TABLE t1(a, b); 
    **   CREATE TABLE t2(c, d);
    **   SELECT * FROM t2, t1 WHERE t2.rowid = t1.a;

    **
    ** The best strategy is to iterate through table t1 first. However it
    ** is not possible to determine this with a simple greedy algorithm.
    ** Since the cost of a linear scan through table t2 is the same 
    ** as the cost of a linear scan through table t1, a simple greedy 
    ** algorithm may choose to use t2 for the outer loop, which is a much
    ** costlier approach.
    */
    nUnconstrained = 0;



    notIndexed = 0;
    for(isOptimal=(iFrom<nTabList-1); isOptimal>=0 && bestJ<0; isOptimal--){



      Bitmask mask;             /* Mask of tables not yet ready */
      for(j=iFrom, pTabItem=&pTabList->a[j]; j<nTabList; j++, pTabItem++){
        int doNotReorder;    /* True if this table should not be reordered */
        WhereCost sCost;     /* Cost information from best[Virtual]Index() */
        ExprList *pOrderBy;  /* ORDER BY clause for index to optimize */
        ExprList *pDist;     /* DISTINCT clause for index to optimize */
  
        doNotReorder =  (pTabItem->jointype & (JT_LEFT|JT_CROSS))!=0;

        if( j!=iFrom && doNotReorder ) break;
        m = getMask(pMaskSet, pTabItem->iCursor);
        if( (m & notReady)==0 ){

          if( j==iFrom ) iFrom++;
          continue;
        }
        mask = (isOptimal ? m : notReady);
        pOrderBy = ((i==0 && ppOrderBy )?*ppOrderBy:0);
        pDist = (i==0 ? pDistinct : 0);
        if( pTabItem->pIndex==0 ) nUnconstrained++;
  
        WHERETRACE(("=== trying table %d with isOptimal=%d ===\n",
                    j, isOptimal));
        assert( pTabItem->pTab );



        if( bestMatchIdx(pParse, pWC, pTabItem, notReady, &sCost) ){
          /* no-op */
        }else
#ifndef SQLITE4_OMIT_VIRTUALTABLE
        if( IsVirtual(pTabItem->pTab) ){
          sqlite4_index_info **pp = &pWInfo->a[j].pIdxInfo;
          bestVirtualIndex(pParse, pWC, pTabItem, mask, notReady, pOrderBy,
                           &sCost, pp);
        }else 
#endif
        {
          bestKVIndex(pParse, pWC, pTabItem, mask, notReady, pOrderBy,
              pDist, &sCost);
        }

        assert( isOptimal || (sCost.used&notReady)==0 );

        /* If an INDEXED BY clause is present, then the plan must use that
        ** index if it uses any index at all */


        assert( pTabItem->pIndex==0 
                  || (sCost.plan.wsFlags & WHERE_NOT_FULLSCAN)==0
                  || sCost.plan.u.pIdx==pTabItem->pIndex );

        if( isOptimal && (sCost.plan.wsFlags & WHERE_NOT_FULLSCAN)==0 ){
          notIndexed |= m;
        }





        /* Conditions under which this table becomes the best so far:
        **
        **   (1) The table must not depend on other tables that have not
        **       yet run.
        **
        **   (2) A full-table-scan plan cannot supercede indexed plan unless
        **       the full-table-scan is an "optimal" plan as defined above.
        **
        **   (3) All tables have an INDEXED BY clause or this table lacks an
        **       INDEXED BY clause or this table uses the specific
        **       index specified by its INDEXED BY clause.  This rule ensures
        **       that a best-so-far is always selected even if an impossible
        **       combination of INDEXED BY clauses are given.  The error
        **       will be detected and relayed back to the application later.
        **       The NEVER() comes about because rule (2) above prevents
        **       An indexable full-table-scan from reaching rule (3).
        **
        **   (4) The plan cost must be lower than prior plans or else the
        **       cost must be the same and the number of rows must be lower.
        */
        if( (sCost.used&notReady)==0                       /* (1) */
            && (bestJ<0 || (notIndexed&m)!=0               /* (2) */
                || (bestPlan.plan.wsFlags & WHERE_NOT_FULLSCAN)==0
                || (sCost.plan.wsFlags & WHERE_NOT_FULLSCAN)!=0)
            && (nUnconstrained==0 || pTabItem->pIndex==0   /* (3) */
                || NEVER((sCost.plan.wsFlags & WHERE_NOT_FULLSCAN)!=0))
            && (bestJ<0 || sCost.rCost<bestPlan.rCost      /* (4) */
                || (sCost.rCost<=bestPlan.rCost 
                 && sCost.plan.nRow<bestPlan.plan.nRow))
        ){
          WHERETRACE(("=== table %d is best so far"
                      " with cost=%g and nRow=%g\n",
                      j, sCost.rCost, sCost.plan.nRow));
          bestPlan = sCost;

          bestJ = j;
        }


        if( doNotReorder ) break;






      }
    }
    assert( bestJ>=0 );
    assert( notReady & getMask(pMaskSet, pTabList->a[bestJ].iCursor) );
    WHERETRACE(("*** Optimizer selects table %d for loop %d"
                " with cost=%g and nRow=%g\n",

                bestJ, pLevel-pWInfo->a, bestPlan.rCost, bestPlan.plan.nRow));



    /* The ALWAYS() that follows was added to hush up clang scan-build */
    if( (bestPlan.plan.wsFlags & WHERE_ORDERBY)!=0 && ALWAYS(ppOrderBy) ){
      *ppOrderBy = 0;
    }
    if( (bestPlan.plan.wsFlags & WHERE_DISTINCT)!=0 ){
      assert( pWInfo->eDistinct==0 );

      pWInfo->eDistinct = WHERE_DISTINCT_ORDERED;
    }
    andFlags &= bestPlan.plan.wsFlags;
    pLevel->plan = bestPlan.plan;

    testcase( bestPlan.plan.wsFlags & WHERE_INDEXED );
    testcase( bestPlan.plan.wsFlags & WHERE_TEMP_INDEX );
    if( bestPlan.plan.wsFlags & (WHERE_INDEXED|WHERE_TEMP_INDEX) ){
      pLevel->iIdxCur = pParse->nTab++;

    }else{
      pLevel->iIdxCur = -1;
    }
    notReady &= ~getMask(pMaskSet, pTabList->a[bestJ].iCursor);
    pLevel->iFrom = (u8)bestJ;
    if( bestPlan.plan.nRow>=(double)1 ){
      pParse->nQueryLoop *= bestPlan.plan.nRow;
    }

    /* Check that if the table scanned by this loop iteration had an
    ** INDEXED BY clause attached to it, that the named index is being
    ** used for the scan. If not, then query compilation has failed.
    ** Return an error.
    */
    pIdx = pTabList->a[bestJ].pIndex;

    if( pIdx ){
      if( (bestPlan.plan.wsFlags & WHERE_INDEXED)==0 ){
        sqlite4ErrorMsg(pParse, "cannot use index: %s", pIdx->zName);
        goto whereBeginError;
      }else{
        /* If an INDEXED BY clause is used, the bestIndex() function is
        ** guaranteed to find the index specified in the INDEXED BY clause
        ** if it find an index at all. */
        assert( bestPlan.plan.u.pIdx==pIdx );
      }
    }
  }

  WHERETRACE(("*** Optimizer Finished ***\n"));
  if( pParse->nErr || db->mallocFailed ){
    goto whereBeginError;

  }

  /* If the total query only selects a single row, then the ORDER BY
  ** clause is irrelevant.
  */
  if( (andFlags & WHERE_UNIQUE)!=0 && ppOrderBy ){
    *ppOrderBy = 0;
  }


  /* If the caller is an UPDATE or DELETE statement that is requesting
  ** to use a one-pass algorithm, determine if this is appropriate.
  ** The one-pass algorithm only works if the WHERE clause constraints
  ** the statement to update a single row.
  */
  assert( (wctrlFlags & WHERE_ONEPASS_DESIRED)==0 || pWInfo->nLevel==1 );
  if( (wctrlFlags & WHERE_ONEPASS_DESIRED)!=0 && (andFlags & WHERE_UNIQUE)!=0 ){

    pWInfo->okOnePass = 1;
    pWInfo->a[0].plan.wsFlags &= ~WHERE_IDX_ONLY;
  }

  /* Open all tables in the pTabList and any indices selected for
  ** searching those tables.
  */
  sqlite4CodeVerifySchema(pParse, -1); /* Insert the cookie verifier Goto */
  notReady = ~(Bitmask)0;
  pWInfo->nRowOut = (double)1;
  for(i=0, pLevel=pWInfo->a; i<nTabList; i++, pLevel++){
    Table *pTab;     /* Table to open */
    int iDb;         /* Index of database containing table/index */


    pTabItem = &pTabList->a[pLevel->iFrom];
    pTab = pTabItem->pTab;
    pLevel->iTabCur = pTabItem->iCursor;
    pWInfo->nRowOut *= pLevel->plan.nRow;
    iDb = sqlite4SchemaToIndex(db, pTab->pSchema);

    if( (pTab->tabFlags & TF_Ephemeral)!=0 || pTab->pSelect ){
      /* Do nothing */
    }else
#ifndef SQLITE4_OMIT_VIRTUALTABLE
    if( (pLevel->plan.wsFlags & WHERE_VIRTUALTABLE)!=0 ){
      const char *pVTab = (const char *)sqlite4GetVTable(db, pTab);
      int iCur = pTabItem->iCursor;
      sqlite4VdbeAddOp4(v, OP_VOpen, iCur, 0, 0, pVTab, P4_VTAB);


    }else
#endif
    if( (pLevel->plan.wsFlags & WHERE_IDX_ONLY)==0
         && (wctrlFlags & WHERE_OMIT_OPEN_CLOSE)==0 ){
      int op = pWInfo->okOnePass ? OP_OpenWrite : OP_OpenRead;
      sqlite4OpenPrimaryKey(pParse, pTabItem->iCursor, iDb, pTab, op);
      testcase( pTab->nCol==BMS-1 );
      testcase( pTab->nCol==BMS );








    }







#ifndef SQLITE4_OMIT_AUTOMATIC_INDEX
    if( (pLevel->plan.wsFlags & WHERE_TEMP_INDEX)!=0 ){
      constructAutomaticIndex(pParse, pWC, pTabItem, notReady, pLevel);
    }else
#endif
    if( (pLevel->plan.wsFlags & WHERE_INDEXED)!=0 ){
      Index *pIx = pLevel->plan.u.pIdx;
      if( pIx->eIndexType==SQLITE4_INDEX_PRIMARYKEY ){
        pLevel->iIdxCur = pTabItem->iCursor;

      }else if( pIx->eIndexType!=SQLITE4_INDEX_FTS5 ){
        KeyInfo *pKey = sqlite4IndexKeyinfo(pParse, pIx);

        int iIdxCur = pLevel->iIdxCur;
        assert( pIx->pSchema==pTab->pSchema );
        assert( iIdxCur>=0 );
        sqlite4VdbeAddOp4(v, OP_OpenRead, iIdxCur, pIx->tnum, iDb,
            (char*)pKey, P4_KEYINFO_HANDOFF);
        VdbeComment((v, "%s", pIx->zName));
      }
    }
    sqlite4CodeVerifySchema(pParse, iDb);
    notReady &= ~getMask(pWC->pMaskSet, pTabItem->iCursor);
  }
  pWInfo->iTop = sqlite4VdbeCurrentAddr(v);
  if( db->mallocFailed ) goto whereBeginError;

  /* Generate the code to do the search.  Each iteration of the for
  ** loop below generates code for a single nested loop of the VM
  ** program.
  */
  notReady = ~(Bitmask)0;
  for(i=0; i<nTabList; i++){
    pLevel = &pWInfo->a[i];
    explainOneScan(pParse, pTabList, pLevel, i, pLevel->iFrom, wctrlFlags);
    notReady = codeOneLoopStart(pWInfo, i, wctrlFlags, notReady, pWhere);
    pWInfo->iContinue = pLevel->addrCont;
  }

#ifdef SQLITE4_TEST  /* For testing and debugging use only */
  /* Record in the query plan information about the current table
  ** and the index used to access it (if any).  If the table itself
  ** is not used, its name is just '{}'.  If no index is used
  ** the index is listed as "{}".  If the primary key is used the
  ** index name is '*'.
  */
  for(i=0; i<nTabList; i++){
    char *z;
    int n;
    pLevel = &pWInfo->a[i];
    pTabItem = &pTabList->a[pLevel->iFrom];
    z = pTabItem->zAlias;
    if( z==0 ) z = pTabItem->pTab->zName;
    n = sqlite4Strlen30(z);
    if( n+nQPlan < sizeof(sqlite4_query_plan)-10 ){
      if( pLevel->plan.wsFlags & WHERE_IDX_ONLY ){
        memcpy(&sqlite4_query_plan[nQPlan], "{}", 2);
        nQPlan += 2;
      }else{
        memcpy(&sqlite4_query_plan[nQPlan], z, n);
        nQPlan += n;
      }
      sqlite4_query_plan[nQPlan++] = ' ';
    }
    if( (pLevel->plan.wsFlags & WHERE_INDEXED)!=0 ){
      n = sqlite4Strlen30(pLevel->plan.u.pIdx->zName);
      if( n+nQPlan < sizeof(sqlite4_query_plan)-2 ){
        memcpy(&sqlite4_query_plan[nQPlan], pLevel->plan.u.pIdx->zName, n);
        nQPlan += n;
        sqlite4_query_plan[nQPlan++] = ' ';
      }
    }else{
      memcpy(&sqlite4_query_plan[nQPlan], "{} ", 3);
      nQPlan += 3;
    }
  }
  while( nQPlan>0 && sqlite4_query_plan[nQPlan-1]==' ' ){
    sqlite4_query_plan[--nQPlan] = 0;
  }
  sqlite4_query_plan[nQPlan] = 0;
  nQPlan = 0;
#endif /* SQLITE4_TEST // Testing and debugging use only */

  /* Record the continuation address in the WhereInfo structure. Then
  ** clean up and return.
  */
  return pWInfo;

  /* Jump here if malloc fails */
whereBeginError:
  if( pWInfo ){
    pParse->nQueryLoop = pWInfo->savedNQueryLoop;
    whereInfoFree(db, pWInfo);
  }
  return 0;
}

/*
** Generate the end of the WHERE loop.  See comments on 
** sqlite4WhereBegin() for additional information.
*/
void sqlite4WhereEnd(WhereInfo *pWInfo){
  Parse *pParse = pWInfo->pParse;
  Vdbe *v = pParse->pVdbe;
  int i;
  WhereLevel *pLevel;

  SrcList *pTabList = pWInfo->pTabList;
  sqlite4 *db = pParse->db;

  /* Generate loop termination code.
  */
  sqlite4ExprCacheClear(pParse);
  for(i=pWInfo->nLevel-1; i>=0; i--){
    pLevel = &pWInfo->a[i];

    sqlite4VdbeResolveLabel(v, pLevel->addrCont);
    if( pLevel->op!=OP_Noop ){
      sqlite4VdbeAddOp2(v, pLevel->op, pLevel->p1, pLevel->p2);
      sqlite4VdbeChangeP5(v, pLevel->p5);
    }
    if( pLevel->plan.wsFlags & WHERE_IN_ABLE && pLevel->u.in.nIn>0 ){
      struct InLoop *pIn;
      int j;
      sqlite4VdbeResolveLabel(v, pLevel->addrNxt);
      for(j=pLevel->u.in.nIn, pIn=&pLevel->u.in.aInLoop[j-1]; j>0; j--, pIn--){
        sqlite4VdbeJumpHere(v, pIn->addrInTop+1);
        sqlite4VdbeAddOp2(v, OP_Next, pIn->iCur, pIn->addrInTop);
        sqlite4VdbeJumpHere(v, pIn->addrInTop-1);
      }
      sqlite4DbFree(db, pLevel->u.in.aInLoop);
    }
    sqlite4VdbeResolveLabel(v, pLevel->addrBrk);
    if( pLevel->iLeftJoin ){
      int addr;
      addr = sqlite4VdbeAddOp1(v, OP_IfPos, pLevel->iLeftJoin);
      assert( (pLevel->plan.wsFlags & WHERE_IDX_ONLY)==0
           || (pLevel->plan.wsFlags & WHERE_INDEXED)!=0 );
      if( (pLevel->plan.wsFlags & WHERE_IDX_ONLY)==0 ){
        sqlite4VdbeAddOp1(v, OP_NullRow, pTabList->a[i].iCursor);
      }
      if( pLevel->iIdxCur>=0 ){
        sqlite4VdbeAddOp1(v, OP_NullRow, pLevel->iIdxCur);
      }
      if( pLevel->op==OP_Return ){
        sqlite4VdbeAddOp2(v, OP_Gosub, pLevel->p1, pLevel->addrFirst);
      }else{
        sqlite4VdbeAddOp2(v, OP_Goto, 0, pLevel->addrFirst);
      }
      sqlite4VdbeJumpHere(v, addr);
    }
  }

  /* The "break" point is here, just past the end of the outer loop.
  ** Set it.
  */
  sqlite4VdbeResolveLabel(v, pWInfo->iBreak);

  /* Close all of the cursors that were opened by sqlite4WhereBegin.
  */
  assert( pWInfo->nLevel==1 || pWInfo->nLevel==pTabList->nSrc );
  for(i=0, pLevel=pWInfo->a; i<pWInfo->nLevel; i++, pLevel++){
    SrcListItem *pTabItem = &pTabList->a[pLevel->iFrom];
    Table *pTab = pTabItem->pTab;
    assert( pTab!=0 );

    if( (pTab->tabFlags & TF_Ephemeral)==0
     && pTab->pSelect==0
     && (pWInfo->wctrlFlags & WHERE_OMIT_OPEN_CLOSE)==0
    ){
      int ws = pLevel->plan.wsFlags;
      if( !pWInfo->okOnePass && (ws & WHERE_IDX_ONLY)==0 ){
        sqlite4VdbeAddOp1(v, OP_Close, pTabItem->iCursor);
      }
      if( (ws & WHERE_INDEXED)!=0 && (ws & WHERE_TEMP_INDEX)==0 ){
        if( pLevel->iIdxCur!=pTabItem->iCursor ){
          sqlite4VdbeAddOp1(v, OP_Close, pLevel->iIdxCur);
        }
      }
    }

    /* If this scan uses an index, make code substitutions to read data
    ** from the index in preference to the table. Sometimes, this means

    ** the table need never be read from. This is a performance boost,
    ** as the vdbe level waits until the table is read before actually
    ** seeking the table cursor to the record corresponding to the current
    ** position in the index.
    ** 
    ** Calls to the code generator in between sqlite4WhereBegin and
    ** sqlite4WhereEnd will have created code that references the table
    ** directly.  This loop scans all that code looking for opcodes
    ** that reference the table and converts them into opcodes that
    ** reference the index.
    */
    if( (pLevel->plan.wsFlags & WHERE_TEMP_INDEX) && !db->mallocFailed ){

      VdbeOp *pOp;
      VdbeOp *pEnd;

      assert( pLevel->plan.u.pIdx );
      assert( pLevel->iTabCur!=pLevel->iIdxCur );
      pOp = sqlite4VdbeGetOp(v, pWInfo->iTop);
      pEnd = &pOp[sqlite4VdbeCurrentAddr(v) - pWInfo->iTop];

      while( pOp<pEnd ){
        if( pOp->p1==pLevel->iTabCur && pOp->opcode==OP_Column ){



          pOp->p1 = pLevel->iIdxCur;
        }
        pOp++;
      }
    }

    if( (pLevel->plan.wsFlags & WHERE_INDEXED)
     && (pLevel->plan.u.pIdx->eIndexType==SQLITE4_INDEX_FTS5)
    ){
      VdbeOp *pOp;
      VdbeOp *pEnd;

      assert( pLevel->iTabCur!=pLevel->iIdxCur );
      pOp = sqlite4VdbeGetOp(v, pWInfo->iTop);
      pEnd = &pOp[sqlite4VdbeCurrentAddr(v) - pWInfo->iTop];

      while( pOp<pEnd ){

        if( pOp->p1==pLevel->iTabCur && pOp->opcode==OP_Mifunction ){
          pOp->p1 = pLevel->iIdxCur;

        }
        pOp++;
      }
    }
  }

  /* Final cleanup
  */
  pParse->nQueryLoop = pWInfo->savedNQueryLoop;
  whereInfoFree(db, pWInfo);
  return;
}







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  /* Allocate and initialize the WhereInfo structure that will become the
  ** return value. A single allocation is used to store the WhereInfo
  ** struct, the contents of WhereInfo.a[], the WhereClause structure
  ** and the WhereMaskSet structure. Since WhereClause contains an 8-byte
  ** field (type Bitmask) it must be aligned on an 8-byte boundary on
  ** some architectures. Hence the ROUND8() below.
  */

  nByteWInfo = ROUND8(sizeof(WhereInfo)+(nTabList-1)*sizeof(WhereLevel));
  pWInfo = sqlite4DbMallocZero(db, nByteWInfo + sizeof(WhereLoop));




  if( db->mallocFailed ){
    sqlite4DbFree(db, pWInfo);
    pWInfo = 0;
    goto whereBeginError;
  }
  pWInfo->nLevel = nTabList;
  pWInfo->pParse = pParse;
  pWInfo->pTabList = pTabList;
  pWInfo->pOrderBy = pOrderBy;
  pWInfo->pResultSet = pResultSet;
  pWInfo->iBreak = sqlite4VdbeMakeLabel(v);

  pWInfo->wctrlFlags = wctrlFlags;
  pWInfo->savedNQueryLoop = pParse->nQueryLoop;
  pMaskSet = &pWInfo->sMaskSet;
  sWLB.pWInfo = pWInfo;

  sWLB.pWC = &pWInfo->sWC;
  sWLB.pNew = (WhereLoop*)&pWInfo->a[nTabList];
  whereLoopInit(sWLB.pNew);
#ifdef SQLITE4_DEBUG
  sWLB.pNew->cId = '*';
#endif

  /* Split the WHERE clause into separate subexpressions where each
  ** subexpression is separated by an AND operator.
  */
  initMaskSet(pMaskSet);
  whereClauseInit(&pWInfo->sWC, pWInfo);
  sqlite4ExprCodeConstants(pParse, pWhere);
  whereSplit(&pWInfo->sWC, pWhere, TK_AND);   /* IMP: R-15842-53296 */
  sqlite4CodeVerifySchema(pParse, -1); /* Insert the cookie verifier Goto */
    
  /* Special case: a WHERE clause that is constant.  Evaluate the
  ** expression and either jump over all of the code or fall thru.
  */
  if( pWhere && (nTabList==0 || sqlite4ExprIsConstantNotJoin(pWhere)) ){
    sqlite4ExprIfFalse(pParse, pWhere, pWInfo->iBreak, SQLITE4_JUMPIFNULL);
    pWhere = 0;
  }

  /* Special case: No FROM clause
  */
  if( nTabList==0 ){
    if( pOrderBy ) pWInfo->bOBSat = 1;
    if( wctrlFlags & WHERE_WANT_DISTINCT ){
      pWInfo->eDistinct = WHERE_DISTINCT_UNIQUE;
    }
  }

  /* Assign a bit from the bitmask to every term in the FROM clause.
  **
  ** When assigning bitmask values to FROM clause cursors, it must be
  ** the case that if X is the bitmask for the N-th FROM clause term then
  ** the bitmask for all FROM clause terms to the left of the N-th term
  ** is (X-1).   An expression from the ON clause of a LEFT JOIN can use
  ** its Expr.iRightJoinTable value to find the bitmask of the right table
  ** of the join.  Subtracting one from the right table bitmask gives a
  ** bitmask for all tables to the left of the join.  Knowing the bitmask
  ** for all tables to the left of a left join is important.  Ticket #3015.
  **





  ** Note that bitmasks are created for all pTabList->nSrc tables in
  ** pTabList, not just the first nTabList tables.  nTabList is normally
  ** equal to pTabList->nSrc but might be shortened to 1 if the
  ** WHERE_ONETABLE_ONLY flag is set.
  */

  for(ii=0; ii<pTabList->nSrc; ii++){
    createMask(pMaskSet, pTabList->a[ii].iCursor);





  }
#ifndef NDEBUG
  {
    Bitmask toTheLeft = 0;
    for(ii=0; ii<pTabList->nSrc; ii++){
      Bitmask m = getMask(pMaskSet, pTabList->a[ii].iCursor);
      assert( (m-1)==toTheLeft );
      toTheLeft |= m;
    }
  }
#endif

  /* Analyze all of the subexpressions.  Note that exprAnalyze() might
  ** add new virtual terms onto the end of the WHERE clause.  We do not
  ** want to analyze these virtual terms, so start analyzing at the end
  ** and work forward so that the added virtual terms are never processed.
  */
  exprAnalyzeAll(pTabList, &pWInfo->sWC);
  if( db->mallocFailed ){
    goto whereBeginError;
  }

  /* If the ORDER BY (or GROUP BY) clause contains references to general
  ** expressions, then we won't be able to satisfy it using indices, so
  ** go ahead and disable it now.
  */
  if( pOrderBy && (wctrlFlags & WHERE_WANT_DISTINCT)!=0 ){
    for(ii=0; ii<pOrderBy->nExpr; ii++){
      Expr *pExpr = sqlite4ExprSkipCollate(pOrderBy->a[ii].pExpr);
      if( pExpr->op!=TK_COLUMN ){
        pWInfo->pOrderBy = pOrderBy = 0;
        break;
      }else if( pExpr->iColumn<0 ){
        break;
      }
    }




















  }

  if( wctrlFlags & WHERE_WANT_DISTINCT ){
    if( isDistinctRedundant(pParse, pTabList, &pWInfo->sWC, pResultSet) ){
      /* The DISTINCT marking is pointless.  Ignore it. */

      pWInfo->eDistinct = WHERE_DISTINCT_UNIQUE;
    }else if( pOrderBy==0 ){
      /* Try to ORDER BY the result set to make distinct processing easier */
      pWInfo->wctrlFlags |= WHERE_DISTINCTBY;
      pWInfo->pOrderBy = pResultSet;
    }



  }


















  /* Construct the WhereLoop objects */
  WHERETRACE(0xffff,("*** Optimizer Start ***\n"));
  if( nTabList!=1 || whereShortCut(&sWLB)==0 ){
    rc = whereLoopAddAll(&sWLB);
    if( rc ) goto whereBeginError;
  

    /* Display all of the WhereLoop objects if wheretrace is enabled */









#ifdef WHERETRACE_ENABLED
    if( sqlite4WhereTrace ){
      WhereLoop *p;







      int i;
      static char zLabel[] = "0123456789abcdefghijklmnopqrstuvwyxz"
                                       "ABCDEFGHIJKLMNOPQRSTUVWYXZ";
      for(p=pWInfo->pLoops, i=0; p; p=p->pNextLoop, i++){
        p->cId = zLabel[i%sizeof(zLabel)];
        whereLoopPrint(p, pTabList);
      }
    }
#endif






  

    wherePathSolver(pWInfo, 0);
    if( db->mallocFailed ) goto whereBeginError;

    if( pWInfo->pOrderBy ){
       wherePathSolver(pWInfo, pWInfo->nRowOut+1);
       if( db->mallocFailed ) goto whereBeginError;

    }




  }



  if( pWInfo->pOrderBy==0 && (db->flags & SQLITE4_ReverseOrder)!=0 ){
     pWInfo->revMask = (Bitmask)(-1);
  }






  if( pParse->nErr || NEVER(db->mallocFailed) ){
    goto whereBeginError;





  }
#ifdef WHERETRACE_ENABLED

  if( sqlite4WhereTrace ){


    int ii;
    sqlite4DebugPrintf("---- Solution nRow=%d", pWInfo->nRowOut);
    if( pWInfo->bOBSat ){


      sqlite4DebugPrintf(" ORDERBY=0x%llx", pWInfo->revMask);


    }
    switch( pWInfo->eDistinct ){
      case WHERE_DISTINCT_UNIQUE: {
        sqlite4DebugPrintf("  DISTINCT=unique");
        break;
      }























      case WHERE_DISTINCT_ORDERED: {










        sqlite4DebugPrintf("  DISTINCT=ordered");
        break;
      }
      case WHERE_DISTINCT_UNORDERED: {
        sqlite4DebugPrintf("  DISTINCT=unordered");
        break;
      }
    }
    sqlite4DebugPrintf("\n");
    for(ii=0; ii<pWInfo->nLevel; ii++){
      whereLoopPrint(pWInfo->a[ii].pWLoop, pTabList);
    }
  }




#endif
  /* Attempt to omit tables from the join that do not effect the result */
  if( pWInfo->nLevel>=2
   && pResultSet!=0
   && OptimizationEnabled(db, SQLITE4_OmitNoopJoin)
  ){
    Bitmask tabUsed = exprListTableUsage(pMaskSet, pResultSet);

    if( pOrderBy ) tabUsed |= exprListTableUsage(pMaskSet, pOrderBy);


    while( pWInfo->nLevel>=2 ){
      WhereTerm *pTerm, *pEnd;
      pLoop = pWInfo->a[pWInfo->nLevel-1].pWLoop;



      if( (pWInfo->pTabList->a[pLoop->iTab].jointype & JT_LEFT)==0 ) break;
      if( (wctrlFlags & WHERE_WANT_DISTINCT)==0
       && (pLoop->wsFlags & WHERE_ONEROW)==0


      ){
        break;







      }
      if( (tabUsed & pLoop->maskSelf)!=0 ) break;
      pEnd = sWLB.pWC->a + sWLB.pWC->nTerm;
      for(pTerm=sWLB.pWC->a; pTerm<pEnd; pTerm++){
        if( (pTerm->prereqAll & pLoop->maskSelf)!=0


         && !ExprHasProperty(pTerm->pExpr, EP_FromJoin)
        ){



          break;




        }
      }

      if( pTerm<pEnd ) break;
      WHERETRACE(0xffff, ("-> drop loop %c not used\n", pLoop->cId));
      pWInfo->nLevel--;

      nTabList--;
    }
  }



  WHERETRACE(0xffff,("*** Optimizer Finished ***\n"));


  pWInfo->pParse->nQueryLoop += pWInfo->nRowOut;

  /* If the caller is an UPDATE or DELETE statement that is requesting
  ** to use a one-pass algorithm, determine if this is appropriate.
  ** The one-pass algorithm only works if the WHERE clause constraints
  ** the statement to update a single row.
  */
  assert( (wctrlFlags & WHERE_ONEPASS_DESIRED)==0 || pWInfo->nLevel==1 );
  if( (wctrlFlags & WHERE_ONEPASS_DESIRED)!=0 
   && (pWInfo->a[0].pWLoop->wsFlags & WHERE_ONEROW)!=0 ){
    pWInfo->okOnePass = 1;
    pWInfo->a[0].pWLoop->wsFlags &= ~WHERE_IDX_ONLY;
  }

  /* Open all tables in the pTabList and any indices selected for
  ** searching those tables.
  */

  notReady = ~(Bitmask)0;

  for(ii=0, pLevel=pWInfo->a; ii<nTabList; ii++, pLevel++){
    Table *pTab;     /* Table to open */
    int iDb;         /* Index of database containing table/index */
    struct SrcListItem *pTabItem;

    pTabItem = &pTabList->a[pLevel->iFrom];
    pTab = pTabItem->pTab;


    iDb = sqlite4SchemaToIndex(db, pTab->pSchema);
    pLoop = pLevel->pWLoop;
    if( (pTab->tabFlags & TF_Ephemeral)!=0 || pTab->pSelect ){
      /* Do nothing */
    }else
#ifndef SQLITE4_OMIT_VIRTUALTABLE
    if( (pLoop->wsFlags & WHERE_VIRTUALTABLE)!=0 ){
      const char *pVTab = (const char *)sqlite4GetVTable(db, pTab);
      int iCur = pTabItem->iCursor;
      sqlite4VdbeAddOp4(v, OP_VOpen, iCur, 0, 0, pVTab, P4_VTAB);
    }else if( IsVirtual(pTab) ){
      /* noop */
    }else
#endif
    if( (pLoop->wsFlags & WHERE_IDX_ONLY)==0
         && (wctrlFlags & WHERE_OMIT_OPEN_CLOSE)==0 ){
      int op = pWInfo->okOnePass ? OP_OpenWrite : OP_OpenRead;
      sqlite4OpenPrimaryKey(pParse, pTabItem->iCursor, iDb, pTab, op);
      testcase( !pWInfo->okOnePass && pTab->nCol==BMS-1 );
      testcase( !pWInfo->okOnePass && pTab->nCol==BMS );
#if 0
      if( !pWInfo->okOnePass && pTab->nCol<BMS ){
        Bitmask b = pTabItem->colUsed;
        int n = 0;
        for(; b; b=b>>1, n++){}
        sqlite4VdbeChangeP4(v, sqlite4VdbeCurrentAddr(v)-1, 
                            SQLITE4_INT_TO_PTR(n), P4_INT32);
        assert( n<=pTab->nCol );
      }
#endif
    }
#if 0
    else{
      sqlite4TableLock(pParse, iDb, pTab->tnum, 0, pTab->zName);
    }
#endif
#ifndef SQLITE4_OMIT_AUTOMATIC_INDEX
    if( (pLoop->wsFlags & WHERE_AUTO_INDEX)!=0 ){
      constructAutomaticIndex(pParse, &pWInfo->sWC, pTabItem, notReady, pLevel);
    }else
#endif
    if( pLoop->wsFlags & WHERE_INDEXED ){
      Index *pIx = pLoop->u.btree.pIndex;
      if( pIx->eIndexType==SQLITE4_INDEX_PRIMARYKEY ){
        pLevel->iIdxCur = pTabItem->iCursor;
      }
      else if( pIx->eIndexType!=SQLITE4_INDEX_FTS5 ){
        KeyInfo *pKey = sqlite4IndexKeyinfo(pParse, pIx);
        /* FIXME:  As an optimization use pTabItem->iCursor if WHERE_IDX_ONLY */
        int iIndexCur = pLevel->iIdxCur = iIdxCur ? iIdxCur : pParse->nTab++;
        assert( pIx->pSchema==pTab->pSchema );
        assert( iIndexCur>=0 );
        sqlite4VdbeAddOp4(v, OP_OpenRead, iIndexCur, pIx->tnum, iDb,
            (char*)pKey, P4_KEYINFO_HANDOFF);
        VdbeComment((v, "%s", pIx->zName));
      }
    }
    sqlite4CodeVerifySchema(pParse, iDb);
    notReady &= ~getMask(&pWInfo->sMaskSet, pTabItem->iCursor);
  }
  pWInfo->iTop = sqlite4VdbeCurrentAddr(v);
  if( db->mallocFailed ) goto whereBeginError;

  /* Generate the code to do the search.  Each iteration of the for
  ** loop below generates code for a single nested loop of the VM
  ** program.
  */
  notReady = ~(Bitmask)0;
  for(ii=0; ii<nTabList; ii++){
    pLevel = &pWInfo->a[ii];
    explainOneScan(pParse, pTabList, pLevel, ii, pLevel->iFrom, wctrlFlags);
    notReady = codeOneLoopStart(pWInfo, ii, notReady);
    pWInfo->iContinue = pLevel->addrCont;
  }












































  /* Done. */



  return pWInfo;

  /* Jump here if malloc fails */
whereBeginError:
  if( pWInfo ){
    pParse->nQueryLoop = pWInfo->savedNQueryLoop;
    whereInfoFree(db, pWInfo);
  }
  return 0;
}

/*
** Generate the end of the WHERE loop.  See comments on 
** sqlite4WhereBegin() for additional information.
*/
void sqlite4WhereEnd(WhereInfo *pWInfo){
  Parse *pParse = pWInfo->pParse;
  Vdbe *v = pParse->pVdbe;
  int i;
  WhereLevel *pLevel;
  WhereLoop *pLoop;
  SrcList *pTabList = pWInfo->pTabList;
  sqlite4 *db = pParse->db;

  /* Generate loop termination code.
  */
  sqlite4ExprCacheClear(pParse);
  for(i=pWInfo->nLevel-1; i>=0; i--){
    pLevel = &pWInfo->a[i];
    pLoop = pLevel->pWLoop;
    sqlite4VdbeResolveLabel(v, pLevel->addrCont);
    if( pLevel->op!=OP_Noop ){
      sqlite4VdbeAddOp2(v, pLevel->op, pLevel->p1, pLevel->p2);
      sqlite4VdbeChangeP5(v, pLevel->p5);
    }
    if( pLoop->wsFlags & WHERE_IN_ABLE && pLevel->u.in.nIn>0 ){
      struct InLoop *pIn;
      int j;
      sqlite4VdbeResolveLabel(v, pLevel->addrNxt);
      for(j=pLevel->u.in.nIn, pIn=&pLevel->u.in.aInLoop[j-1]; j>0; j--, pIn--){
        sqlite4VdbeJumpHere(v, pIn->addrInTop+1);
        sqlite4VdbeAddOp2(v, pIn->eEndLoopOp, pIn->iCur, pIn->addrInTop);
        sqlite4VdbeJumpHere(v, pIn->addrInTop-1);
      }
      sqlite4DbFree(db, pLevel->u.in.aInLoop);
    }
    sqlite4VdbeResolveLabel(v, pLevel->addrBrk);
    if( pLevel->iLeftJoin ){
      int addr;
      addr = sqlite4VdbeAddOp1(v, OP_IfPos, pLevel->iLeftJoin);
      assert( (pLoop->wsFlags & WHERE_IDX_ONLY)==0
           || (pLoop->wsFlags & WHERE_INDEXED)!=0 );
      if( (pLoop->wsFlags & WHERE_IDX_ONLY)==0 ){
        sqlite4VdbeAddOp1(v, OP_NullRow, pTabList->a[i].iCursor);
      }
      if( pLoop->wsFlags & WHERE_INDEXED ){
        sqlite4VdbeAddOp1(v, OP_NullRow, pLevel->iIdxCur);
      }
      if( pLevel->op==OP_Return ){
        sqlite4VdbeAddOp2(v, OP_Gosub, pLevel->p1, pLevel->addrFirst);
      }else{
        sqlite4VdbeAddOp2(v, OP_Goto, 0, pLevel->addrFirst);
      }
      sqlite4VdbeJumpHere(v, addr);
    }
  }

  /* The "break" point is here, just past the end of the outer loop.
  ** Set it.
  */
  sqlite4VdbeResolveLabel(v, pWInfo->iBreak);

  /* Close all of the cursors that were opened by sqlite4WhereBegin.
  */
  assert( pWInfo->nLevel<=pTabList->nSrc );
  for(i=0, pLevel=pWInfo->a; i<pWInfo->nLevel; i++, pLevel++){
    struct SrcListItem *pTabItem = &pTabList->a[pLevel->iFrom];
    Table *pTab = pTabItem->pTab;
    assert( pTab!=0 );
    pLoop = pLevel->pWLoop;
    if( (pTab->tabFlags & TF_Ephemeral)==0
     && pTab->pSelect==0
     && (pWInfo->wctrlFlags & WHERE_OMIT_OPEN_CLOSE)==0
    ){
      int ws = pLoop->wsFlags;
      if( !pWInfo->okOnePass && (ws & WHERE_IDX_ONLY)==0 ){
        sqlite4VdbeAddOp1(v, OP_Close, pTabItem->iCursor);
      }
      if( (ws & WHERE_INDEXED)!=0 && (ws & (WHERE_IPK|WHERE_AUTO_INDEX))==0 ){
        if( pLevel->iIdxCur!=pTabItem->iCursor ){
          sqlite4VdbeAddOp1(v, OP_Close, pLevel->iIdxCur);
        }
      }
    }

    /* If this scan uses an index, make VDBE code substitutions to read data
    ** from the index instead of from the table where possible.  In some cases
    ** this optimization prevents the table from ever being read, which can
    ** yield a significant performance boost.



    ** 
    ** Calls to the code generator in between sqlite4WhereBegin and
    ** sqlite4WhereEnd will have created code that references the table
    ** directly.  This loop scans all that code looking for opcodes
    ** that reference the table and converts them into opcodes that
    ** reference the index.
    */
    if( (pLoop->wsFlags & WHERE_AUTO_INDEX) && !db->mallocFailed ){
      int k, j, last;
      VdbeOp *pOp;
      Index *pIdx = pLoop->u.btree.pIndex;



      pOp = sqlite4VdbeGetOp(v, pWInfo->iTop);
      last = sqlite4VdbeCurrentAddr(v);
      for(k=pWInfo->iTop; k<last; k++, pOp++){
        if( pOp->p1!=pLevel->iTabCur ) continue;
        if( pOp->opcode==OP_Column ){
          for(j=0; j<pIdx->nColumn; j++){
            if( pOp->p2==pIdx->aiColumn[j] ){
              pOp->p2 = j;
              pOp->p1 = pLevel->iIdxCur;




              break;





            }



          }

          assert( (pLoop->wsFlags & WHERE_IDX_ONLY)==0 || j<pIdx->nColumn );
        }else if( pOp->opcode==OP_Rowid ){
          pOp->p1 = pLevel->iIdxCur;
          pOp->opcode = OP_IdxRowid;
        }

      }
    }
  }

  /* Final cleanup
  */
  pParse->nQueryLoop = pWInfo->savedNQueryLoop;
  whereInfoFree(db, pWInfo);
  return;
}

Changes to test/analyze4.test.

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    INSERT INTO t1 SELECT a+32, b FROM t1;
    INSERT INTO t1 SELECT a+64, b FROM t1;
    ANALYZE;
  }

  # Should choose the t1a index since it is more specific than t1b.
  db eval {EXPLAIN QUERY PLAN SELECT * FROM t1 WHERE a=5 AND b IS NULL}
} {0 0 0 {SEARCH TABLE t1 USING INDEX t1a (a=?) (~1 rows)}}

# Verify that the t1b index shows that it does not narrow down the
# search any at all.
#
do_test analyze4-1.1 {
  db eval {
    SELECT idx, stat FROM sqlite_stat1 WHERE tbl='t1' ORDER BY idx;







|







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    INSERT INTO t1 SELECT a+32, b FROM t1;
    INSERT INTO t1 SELECT a+64, b FROM t1;
    ANALYZE;
  }

  # Should choose the t1a index since it is more specific than t1b.
  db eval {EXPLAIN QUERY PLAN SELECT * FROM t1 WHERE a=5 AND b IS NULL}
} {0 0 0 {SEARCH TABLE t1 USING INDEX t1a (a=?)}}

# Verify that the t1b index shows that it does not narrow down the
# search any at all.
#
do_test analyze4-1.1 {
  db eval {
    SELECT idx, stat FROM sqlite_stat1 WHERE tbl='t1' ORDER BY idx;

Changes to test/between.test.

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    CREATE INDEX i1zyx ON t1(z,y,x);
    COMMIT;
  }
} {}

# This procedure executes the SQL.  Then it appends to the result the
# "sort" or "nosort" keyword depending on whether or not any sorting
# is done.  Then it appends the ::sqlite_query_plan variable.
#
proc queryplan {sql} {
  set ::sqlite_sort_count 0
  set data [execsql $sql]
  if {$::sqlite_sort_count} {set x sort} {set x nosort}
  lappend data $x










  return [concat $data $::sqlite_query_plan]
}

do_test between-1.1.1 {
  queryplan {
    SELECT * FROM t1 WHERE w BETWEEN 5 AND 6 ORDER BY +w
  }
} {5 2 36 38 6 2 49 51 sort t1 i1w}
do_test between-1.1.2 {
  queryplan {
    SELECT * FROM t1 WHERE +w BETWEEN 5 AND 6 ORDER BY +w
  }
} {5 2 36 38 6 2 49 51 sort t1 {}}
do_test between-1.2.1 {
  queryplan {
    SELECT * FROM t1 WHERE w BETWEEN 5 AND 65-y ORDER BY +w
  }
} {5 2 36 38 6 2 49 51 sort t1 i1w}
do_test between-1.2.2 {
  queryplan {
    SELECT * FROM t1 WHERE +w BETWEEN 5 AND 65-y ORDER BY +w
  }
} {5 2 36 38 6 2 49 51 sort t1 {}}
do_test between-1.3.1 {
  queryplan {
    SELECT * FROM t1 WHERE w BETWEEN 41-y AND 6 ORDER BY +w
  }
} {5 2 36 38 6 2 49 51 sort t1 i1w}
do_test between-1.3.2 {
  queryplan {
    SELECT * FROM t1 WHERE +w BETWEEN 41-y AND 6 ORDER BY +w
  }
} {5 2 36 38 6 2 49 51 sort t1 {}}
do_test between-1.4 {
  queryplan {
    SELECT * FROM t1 WHERE w BETWEEN 41-y AND 65-y ORDER BY +w
  }
} {5 2 36 38 6 2 49 51 sort t1 {}}
do_test between-1.5.1 {
  queryplan {
    SELECT * FROM t1 WHERE 26 BETWEEN y AND z ORDER BY +w
  }
} {4 2 25 27 sort t1 i1zyx}
do_test between-1.5.2 {
  queryplan {
    SELECT * FROM t1 WHERE 26 BETWEEN +y AND z ORDER BY +w
  }
} {4 2 25 27 sort t1 i1zyx}
do_test between-1.5.3 {
  queryplan {
    SELECT * FROM t1 WHERE 26 BETWEEN y AND +z ORDER BY +w
  }
} {4 2 25 27 sort t1 {}}


finish_test







|






>
>
>
>
>
>
>
>
>
>
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    CREATE INDEX i1zyx ON t1(z,y,x);
    COMMIT;
  }
} {}

# This procedure executes the SQL.  Then it appends to the result the
# "sort" or "nosort" keyword depending on whether or not any sorting
# is done.  Then it appends the names of the table and index used.
#
proc queryplan {sql} {
  set ::sqlite_sort_count 0
  set data [execsql $sql]
  if {$::sqlite_sort_count} {set x sort} {set x nosort}
  lappend data $x
  set eqp [execsql "EXPLAIN QUERY PLAN $sql"]
  # puts eqp=$eqp
  foreach {a b c x} $eqp {
    if {[regexp { TABLE (\w+ AS )?(\w+) USING.* INDEX (\w+)\y} \
        $x all as tab idx]} {
      lappend data $tab $idx
    } elseif {[regexp { TABLE (\w+ AS )?(\w+)\y} $x all as tab]} {
      lappend data $tab *
    }
  }
  return $data   
}

do_test between-1.1.1 {
  queryplan {
    SELECT * FROM t1 WHERE w BETWEEN 5 AND 6 ORDER BY +w
  }
} {5 2 36 38 6 2 49 51 sort t1 i1w}
do_test between-1.1.2 {
  queryplan {
    SELECT * FROM t1 WHERE +w BETWEEN 5 AND 6 ORDER BY +w
  }
} {5 2 36 38 6 2 49 51 sort t1 t1}
do_test between-1.2.1 {
  queryplan {
    SELECT * FROM t1 WHERE w BETWEEN 5 AND 65-y ORDER BY +w
  }
} {5 2 36 38 6 2 49 51 sort t1 i1w}
do_test between-1.2.2 {
  queryplan {
    SELECT * FROM t1 WHERE +w BETWEEN 5 AND 65-y ORDER BY +w
  }
} {5 2 36 38 6 2 49 51 sort t1 t1}
do_test between-1.3.1 {
  queryplan {
    SELECT * FROM t1 WHERE w BETWEEN 41-y AND 6 ORDER BY +w
  }
} {5 2 36 38 6 2 49 51 sort t1 i1w}
do_test between-1.3.2 {
  queryplan {
    SELECT * FROM t1 WHERE +w BETWEEN 41-y AND 6 ORDER BY +w
  }
} {5 2 36 38 6 2 49 51 sort t1 t1}
do_test between-1.4 {
  queryplan {
    SELECT * FROM t1 WHERE w BETWEEN 41-y AND 65-y ORDER BY +w
  }
} {5 2 36 38 6 2 49 51 sort t1 t1}
do_test between-1.5.1 {
  queryplan {
    SELECT * FROM t1 WHERE 26 BETWEEN y AND z ORDER BY +w
  }
} {4 2 25 27 sort t1 i1zyx}
do_test between-1.5.2 {
  queryplan {
    SELECT * FROM t1 WHERE 26 BETWEEN +y AND z ORDER BY +w
  }
} {4 2 25 27 sort t1 i1zyx}
do_test between-1.5.3 {
  queryplan {
    SELECT * FROM t1 WHERE 26 BETWEEN y AND +z ORDER BY +w
  }
} {4 2 25 27 sort t1 t1}


finish_test

Changes to test/collate4.test.

85
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  cksort {SELECT b FROM collate4t1 ORDER BY b}
} {{} A B a b nosort}
do_test collate4-1.1.5 {
  cksort {SELECT b FROM collate4t1 ORDER BY b COLLATE TEXT}
} {{} A B a b nosort}
do_test collate4-1.1.6 {
  cksort {SELECT b FROM collate4t1 ORDER BY b COLLATE NOCASE}
} {{} a A b B sort}

do_test collate4-1.1.7 {
  execsql {
    CREATE TABLE collate4t2(
      a PRIMARY KEY COLLATE NOCASE, 
      b UNIQUE COLLATE TEXT
    );







|







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  cksort {SELECT b FROM collate4t1 ORDER BY b}
} {{} A B a b nosort}
do_test collate4-1.1.5 {
  cksort {SELECT b FROM collate4t1 ORDER BY b COLLATE TEXT}
} {{} A B a b nosort}
do_test collate4-1.1.6 {
  cksort {SELECT b FROM collate4t1 ORDER BY b COLLATE NOCASE}
} {{} A a B b sort}

do_test collate4-1.1.7 {
  execsql {
    CREATE TABLE collate4t2(
      a PRIMARY KEY COLLATE NOCASE, 
      b UNIQUE COLLATE TEXT
    );
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    INSERT INTO collate4t4 VALUES( 'A', 'A' );
    CREATE INDEX collate4i3 ON collate4t4(a COLLATE TEXT);
    CREATE INDEX collate4i4 ON collate4t4(b COLLATE NOCASE);
  }
} {}
do_test collate4-1.1.22 {
  cksort {SELECT a FROM collate4t4 ORDER BY a}
} {{} a A b B sort}
do_test collate4-1.1.23 {
  cksort {SELECT a FROM collate4t4 ORDER BY a COLLATE NOCASE}
} {{} a A b B sort}
do_test collate4-1.1.24 {
  cksort {SELECT a FROM collate4t4 ORDER BY a COLLATE TEXT}
} {{} A B a b nosort}
do_test collate4-1.1.25 {
  cksort {SELECT b FROM collate4t4 ORDER BY b}
} {{} A B a b sort}
do_test collate4-1.1.26 {







|


|







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171
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    INSERT INTO collate4t4 VALUES( 'A', 'A' );
    CREATE INDEX collate4i3 ON collate4t4(a COLLATE TEXT);
    CREATE INDEX collate4i4 ON collate4t4(b COLLATE NOCASE);
  }
} {}
do_test collate4-1.1.22 {
  cksort {SELECT a FROM collate4t4 ORDER BY a}
} {{} A a B b sort}
do_test collate4-1.1.23 {
  cksort {SELECT a FROM collate4t4 ORDER BY a COLLATE NOCASE}
} {{} A a B b sort}
do_test collate4-1.1.24 {
  cksort {SELECT a FROM collate4t4 ORDER BY a COLLATE TEXT}
} {{} A B a b nosort}
do_test collate4-1.1.25 {
  cksort {SELECT b FROM collate4t4 ORDER BY b}
} {{} A B a b sort}
do_test collate4-1.1.26 {
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215
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219
220
221
222
223
224
225
226
227
  cksort {SELECT a FROM collate4t1 ORDER BY a COLLATE text}
} {{} A B a b sort}
do_test collate4-1.2.4 {
  cksort {SELECT a FROM collate4t1 ORDER BY a, b}
} {{} A a B b nosort}
do_test collate4-1.2.5 {
  cksort {SELECT a FROM collate4t1 ORDER BY a, b COLLATE nocase}
} {{} a A b B sort}
do_test collate4-1.2.6 {
  cksort {SELECT a FROM collate4t1 ORDER BY a, b COLLATE text}
} {{} A a B b nosort}

do_test collate4-1.2.7 {
  execsql {
    CREATE TABLE collate4t2(







|







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215
216
217
218
219
220
221
222
223
224
225
226
227
  cksort {SELECT a FROM collate4t1 ORDER BY a COLLATE text}
} {{} A B a b sort}
do_test collate4-1.2.4 {
  cksort {SELECT a FROM collate4t1 ORDER BY a, b}
} {{} A a B b nosort}
do_test collate4-1.2.5 {
  cksort {SELECT a FROM collate4t1 ORDER BY a, b COLLATE nocase}
} {{} A a B b sort}
do_test collate4-1.2.6 {
  cksort {SELECT a FROM collate4t1 ORDER BY a, b COLLATE text}
} {{} A a B b nosort}

do_test collate4-1.2.7 {
  execsql {
    CREATE TABLE collate4t2(
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266
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272
273
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275
276
277
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279
    INSERT INTO collate4t3 VALUES( 'B', 'B' );
    INSERT INTO collate4t3 VALUES( 'A', 'A' );
    CREATE INDEX collate4i2 ON collate4t3(a COLLATE TEXT, b COLLATE NOCASE);
  }
} {}
do_test collate4-1.2.15 {
  cksort {SELECT a FROM collate4t3 ORDER BY a}
} {{} a A b B sort}
do_test collate4-1.2.16 {
  cksort {SELECT a FROM collate4t3 ORDER BY a COLLATE nocase}
} {{} a A b B sort}
do_test collate4-1.2.17 {
  cksort {SELECT a FROM collate4t3 ORDER BY a COLLATE text}
} {{} A B a b nosort}
do_test collate4-1.2.18 {
  cksort {SELECT a FROM collate4t3 ORDER BY a COLLATE text, b}
} {{} A B a b sort}
do_test collate4-1.2.19 {







|


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    INSERT INTO collate4t3 VALUES( 'B', 'B' );
    INSERT INTO collate4t3 VALUES( 'A', 'A' );
    CREATE INDEX collate4i2 ON collate4t3(a COLLATE TEXT, b COLLATE NOCASE);
  }
} {}
do_test collate4-1.2.15 {
  cksort {SELECT a FROM collate4t3 ORDER BY a}
} {{} A a B b sort}
do_test collate4-1.2.16 {
  cksort {SELECT a FROM collate4t3 ORDER BY a COLLATE nocase}
} {{} A a B b sort}
do_test collate4-1.2.17 {
  cksort {SELECT a FROM collate4t3 ORDER BY a COLLATE text}
} {{} A B a b nosort}
do_test collate4-1.2.18 {
  cksort {SELECT a FROM collate4t3 ORDER BY a COLLATE text, b}
} {{} A B a b sort}
do_test collate4-1.2.19 {
605
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618
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620
621
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  execsql {
    DROP INDEX collate4i1;
    CREATE INDEX collate4i1 ON collate4t1(a COLLATE NUMERIC);
  }
  count {
    SELECT min(a) FROM collate4t1;
  }
} {10 5}
do_test collate4-4.6 {
  count {
    SELECT max(a) FROM collate4t1;
  }
} {20 5}
do_test collate4-4.7 {
  execsql {
    DROP TABLE collate4t1;
  }
} {}

# Also test the scalar min() and max() functions.







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  execsql {
    DROP INDEX collate4i1;
    CREATE INDEX collate4i1 ON collate4t1(a COLLATE NUMERIC);
  }
  count {
    SELECT min(a) FROM collate4t1;
  }
} {10 9}
do_test collate4-4.6 {
  count {
    SELECT max(a) FROM collate4t1;
  }
} {20 9}
do_test collate4-4.7 {
  execsql {
    DROP TABLE collate4t1;
  }
} {}

# Also test the scalar min() and max() functions.

Changes to test/descidx3.test.

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} {9 7 6 8 3 4 2 5}

ifcapable subquery {
  # If the subquery capability is not compiled in to the binary, then
  # the IN(...) operator is not available. Hence these tests cannot be 
  # run.
  do_test descidx3-4.1 {
    execsql {
      UPDATE t1 SET a=2 WHERE i<6;
      SELECT i FROM t1 WHERE a IN (1,2) AND b>0 AND b<'zzz';
    }
  } {8 6 2 4 3}
  do_test descidx3-4.2 {
    execsql {
      UPDATE t1 SET a=1;
      SELECT i FROM t1 WHERE a IN (1,2) AND b>0 AND b<'zzz';
    }
  } {2 4 3 8 6}
  do_test descidx3-4.3 {







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} {9 7 6 8 3 4 2 5}

ifcapable subquery {
  # If the subquery capability is not compiled in to the binary, then
  # the IN(...) operator is not available. Hence these tests cannot be 
  # run.
  do_test descidx3-4.1 {
    lsort [execsql {
      UPDATE t1 SET a=2 WHERE i<6;
      SELECT i FROM t1 WHERE a IN (1,2) AND b>0 AND b<'zzz';
    }]
  } {2 3 4 6 8}
  do_test descidx3-4.2 {
    execsql {
      UPDATE t1 SET a=1;
      SELECT i FROM t1 WHERE a IN (1,2) AND b>0 AND b<'zzz';
    }
  } {2 4 3 8 6}
  do_test descidx3-4.3 {

Changes to test/e_createtable.test.

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#
do_execsql_test 4.10.0 {
  CREATE TABLE t1(a, b PRIMARY KEY);
  CREATE TABLE t2(a, b, c, UNIQUE(b, c));
}
do_createtable_tests 4.10 {
  1    "EXPLAIN QUERY PLAN SELECT * FROM t1 WHERE b = 5" 
       {0 0 0 {SEARCH TABLE t1 USING PRIMARY KEY (b=?) (~1 rows)}}

  2    "EXPLAIN QUERY PLAN SELECT * FROM t2 ORDER BY b, c"
       {0 0 0 {SCAN TABLE t2 USING INDEX sqlite_t2_unique1 (~1000000 rows)}}

  3    "EXPLAIN QUERY PLAN SELECT * FROM t2 WHERE b=10 AND c>10"
       {0 0 0 {SEARCH TABLE t2 USING INDEX sqlite_t2_unique1 (b=? AND c>?) (~2 rows)}}
}

# EVIDENCE-OF: R-45493-35653 A CHECK constraint may be attached to a
# column definition or specified as a table constraint. In practice it
# makes no difference.
#
#   All the tests that deal with CHECK constraints below (4.11.* and 







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#
do_execsql_test 4.10.0 {
  CREATE TABLE t1(a, b PRIMARY KEY);
  CREATE TABLE t2(a, b, c, UNIQUE(b, c));
}
do_createtable_tests 4.10 {
  1    "EXPLAIN QUERY PLAN SELECT * FROM t1 WHERE b = 5" 
       {0 0 0 {SEARCH TABLE t1 USING INDEX t1 (b=?)}}

  2    "EXPLAIN QUERY PLAN SELECT * FROM t2 ORDER BY b, c"
       {0 0 0 {SCAN TABLE t2 USING INDEX sqlite_t2_unique1}}

  3    "EXPLAIN QUERY PLAN SELECT * FROM t2 WHERE b=10 AND c>10"
       {0 0 0 {SEARCH TABLE t2 USING INDEX sqlite_t2_unique1 (b=? AND c>?)}}
}

# EVIDENCE-OF: R-45493-35653 A CHECK constraint may be attached to a
# column definition or specified as a table constraint. In practice it
# makes no difference.
#
#   All the tests that deal with CHECK constraints below (4.11.* and 

Changes to test/e_fkey.test.

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  }
} {}
do_execsql_test e_fkey-25.2 {
  PRAGMA foreign_keys = OFF;
  EXPLAIN QUERY PLAN DELETE FROM artist WHERE 1;
  EXPLAIN QUERY PLAN SELECT rowid FROM track WHERE trackartist = ?;
} {
  0 0 0 {SCAN TABLE artist (~1000000 rows)} 
  0 0 0 {SCAN TABLE track (~100000 rows)}
}
do_execsql_test e_fkey-25.3 {
  PRAGMA foreign_keys = ON;
  EXPLAIN QUERY PLAN DELETE FROM artist WHERE 1;
} {
  0 0 0 {SCAN TABLE artist (~1000000 rows)} 
  0 0 0 {SCAN TABLE track (~100000 rows)}
}
do_test e_fkey-25.4 {
  execsql {
    INSERT INTO artist VALUES(5, 'artist 5');
    INSERT INTO artist VALUES(6, 'artist 6');
    INSERT INTO artist VALUES(7, 'artist 7');
    INSERT INTO track VALUES(1, 'track 1', 5);







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  }
} {}
do_execsql_test e_fkey-25.2 {
  PRAGMA foreign_keys = OFF;
  EXPLAIN QUERY PLAN DELETE FROM artist WHERE 1;
  EXPLAIN QUERY PLAN SELECT rowid FROM track WHERE trackartist = ?;
} {
  0 0 0 {SCAN TABLE artist USING INDEX artist} 
  0 0 0 {SCAN TABLE track USING INDEX track}
}
do_execsql_test e_fkey-25.3 {
  PRAGMA foreign_keys = ON;
  EXPLAIN QUERY PLAN DELETE FROM artist WHERE 1;
} {
  0 0 0 {SCAN TABLE artist USING INDEX artist}
  0 0 0 {SCAN TABLE track USING INDEX track}
}
do_test e_fkey-25.4 {
  execsql {
    INSERT INTO artist VALUES(5, 'artist 5');
    INSERT INTO artist VALUES(6, 'artist 6');
    INSERT INTO artist VALUES(7, 'artist 7');
    INSERT INTO track VALUES(1, 'track 1', 5);
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} {}
do_test e_fkey-27.2 {
  eqp { INSERT INTO artist VALUES(?, ?) }
} {}
do_execsql_test e_fkey-27.3 {
  EXPLAIN QUERY PLAN UPDATE artist SET artistid = ?, artistname = ?
} {
  0 0 0 {SCAN TABLE artist (~1000000 rows)} 
  0 0 0 {SEARCH TABLE track USING INDEX trackindex (trackartist=?) (~10 rows)} 
  0 0 0 {SEARCH TABLE track USING INDEX trackindex (trackartist=?) (~10 rows)}
}
do_execsql_test e_fkey-27.4 {
  EXPLAIN QUERY PLAN DELETE FROM artist
} {
  0 0 0 {SCAN TABLE artist (~1000000 rows)} 
  0 0 0 {SEARCH TABLE track USING INDEX trackindex (trackartist=?) (~10 rows)}
}


###########################################################################
### SECTION 4.1: Composite Foreign Key Constraints
###########################################################################








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} {}
do_test e_fkey-27.2 {
  eqp { INSERT INTO artist VALUES(?, ?) }
} {}
do_execsql_test e_fkey-27.3 {
  EXPLAIN QUERY PLAN UPDATE artist SET artistid = ?, artistname = ?
} {
  0 0 0 {SCAN TABLE artist USING INDEX artist}
  0 0 0 {SEARCH TABLE track USING INDEX trackindex (trackartist=?)} 
  0 0 0 {SEARCH TABLE track USING INDEX trackindex (trackartist=?)}
}
do_execsql_test e_fkey-27.4 {
  EXPLAIN QUERY PLAN DELETE FROM artist
} {
  0 0 0 {SCAN TABLE artist USING INDEX artist} 
  0 0 0 {SEARCH TABLE track USING INDEX trackindex (trackartist=?)}
}


###########################################################################
### SECTION 4.1: Composite Foreign Key Constraints
###########################################################################

Changes to test/like.test.

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# is performed.
#
do_test like-3.1 {
  set sqlite_like_count 0
  queryplan {
    SELECT x FROM t1 WHERE x LIKE 'abc%' ORDER BY 1;
  }
} {ABC {ABC abc xyz} abc abcd sort t1 *}
do_test like-3.2 {
  set sqlite_like_count
} {12}

# With an index on t1.x and case sensitivity on, optimize completely.
#
do_test like-3.3 {







|







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# is performed.
#
do_test like-3.1 {
  set sqlite_like_count 0
  queryplan {
    SELECT x FROM t1 WHERE x LIKE 'abc%' ORDER BY 1;
  }
} {ABC {ABC abc xyz} abc abcd sort t1 t1}
do_test like-3.2 {
  set sqlite_like_count
} {12}

# With an index on t1.x and case sensitivity on, optimize completely.
#
do_test like-3.3 {
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  db eval {
    PRAGMA case_sensitive_like=on;
    DROP INDEX i1;
  }
  queryplan {
    SELECT x FROM t1 WHERE x LIKE 'abc%' ORDER BY 1;
  }
} {abc abcd sort t1 *}
do_test like-3.16 {
  set sqlite_like_count
} 12

# No GLOB optimization without an index.
#
do_test like-3.17 {
  set sqlite_like_count 0
  queryplan {
    SELECT x FROM t1 WHERE x GLOB 'abc*' ORDER BY 1;
  }
} {abc abcd sort t1 *}
do_test like-3.18 {
  set sqlite_like_count
} 12

# GLOB is optimized regardless of the case_sensitive_like setting.
#
do_test like-3.19 {







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  db eval {
    PRAGMA case_sensitive_like=on;
    DROP INDEX i1;
  }
  queryplan {
    SELECT x FROM t1 WHERE x LIKE 'abc%' ORDER BY 1;
  }
} {abc abcd sort t1 t1}
do_test like-3.16 {
  set sqlite_like_count
} 12

# No GLOB optimization without an index.
#
do_test like-3.17 {
  set sqlite_like_count 0
  queryplan {
    SELECT x FROM t1 WHERE x GLOB 'abc*' ORDER BY 1;
  }
} {abc abcd sort t1 t1}
do_test like-3.18 {
  set sqlite_like_count
} 12

# GLOB is optimized regardless of the case_sensitive_like setting.
#
do_test like-3.19 {
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  }
} {12}
do_test like-11.1 {
  db eval {PRAGMA case_sensitive_like=OFF;}
  queryplan {
    SELECT b FROM t11 WHERE b LIKE 'abc%' ORDER BY a;
  }
} {abc abcd ABC ABCD nosort t11 *}
do_test like-11.2 {
  db eval {PRAGMA case_sensitive_like=ON;}
  queryplan {
    SELECT b FROM t11 WHERE b LIKE 'abc%' ORDER BY a;
  }
} {abc abcd nosort t11 *}
do_test like-11.3 {
  db eval {
    PRAGMA case_sensitive_like=OFF;
    CREATE INDEX t11b ON t11(b);
  }
  queryplan {
    SELECT b FROM t11 WHERE b LIKE 'abc%' ORDER BY +a;
  }
} {abc abcd ABC ABCD sort t11 t11b}
do_test like-11.4 {
  db eval {PRAGMA case_sensitive_like=ON;}
  queryplan {
    SELECT b FROM t11 WHERE b LIKE 'abc%' ORDER BY a;
  }
} {abc abcd nosort t11 *}
do_test like-11.5 {
  db eval {
    PRAGMA case_sensitive_like=OFF;
    DROP INDEX t11b;
    CREATE INDEX t11bnc ON t11(b COLLATE nocase);
  }
  queryplan {







|





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  }
} {12}
do_test like-11.1 {
  db eval {PRAGMA case_sensitive_like=OFF;}
  queryplan {
    SELECT b FROM t11 WHERE b LIKE 'abc%' ORDER BY a;
  }
} {abc abcd ABC ABCD nosort t11 t11}
do_test like-11.2 {
  db eval {PRAGMA case_sensitive_like=ON;}
  queryplan {
    SELECT b FROM t11 WHERE b LIKE 'abc%' ORDER BY a;
  }
} {abc abcd nosort t11 t11}
do_test like-11.3 {
  db eval {
    PRAGMA case_sensitive_like=OFF;
    CREATE INDEX t11b ON t11(b);
  }
  queryplan {
    SELECT b FROM t11 WHERE b LIKE 'abc%' ORDER BY +a;
  }
} {abc abcd ABC ABCD sort t11 t11b}
do_test like-11.4 {
  db eval {PRAGMA case_sensitive_like=ON;}
  queryplan {
    SELECT b FROM t11 WHERE b LIKE 'abc%' ORDER BY a;
  }
} {abc abcd nosort t11 t11}
do_test like-11.5 {
  db eval {
    PRAGMA case_sensitive_like=OFF;
    DROP INDEX t11b;
    CREATE INDEX t11bnc ON t11(b COLLATE nocase);
  }
  queryplan {

Changes to test/permutations.test.

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#   src4
#   veryquick
#   quick
#   full
#
lappend ::testsuitelist xxx


test_suite "src4" -prefix "" -description {
} -files {
  simple.test simple2.test
  lsm1.test lsm2.test lsm3.test lsm4.test lsm5.test
  csr1.test
  ckpt1.test
  mc1.test
  fts5expr1.test fts5query1.test fts5rnd1.test fts5create.test
  fts5snippet.test

  alter.test alter3.test alter4.test
  analyze.test analyze3.test analyze4.test analyze5.test 
  analyze6.test analyze7.test analyze8.test
  auth.test auth2.test auth3.test auth4.test
  aggerror.test
  attach.test attach3.test attach4.test







>







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<







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#   src4
#   veryquick
#   quick
#   full
#
lappend ::testsuitelist xxx

# fts5expr1.test fts5query1.test fts5rnd1.test fts5create.test fts5snippet.test
test_suite "src4" -prefix "" -description {
} -files {
  simple.test simple2.test
  lsm1.test lsm2.test lsm3.test lsm4.test lsm5.test
  csr1.test
  ckpt1.test
  mc1.test



  alter.test alter3.test alter4.test
  analyze.test analyze3.test analyze4.test analyze5.test 
  analyze6.test analyze7.test analyze8.test
  auth.test auth2.test auth3.test auth4.test
  aggerror.test
  attach.test attach3.test attach4.test

Changes to test/simple.test.

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do_execsql_test 38.2 {
  CREATE VIEW v1 AS SELECT a, b FROM t1;
  CREATE TRIGGER tr1 INSTEAD OF DELETE ON v1 BEGIN
    INSERT INTO log VALUES(old.b, old.a);
  END;
}
do_execsql_test 38.3 {



  DELETE FROM v1 WHERE a = 3;


  SELECT * FROM log;
} {4 3}

#-------------------------------------------------------------------------
reset_db
do_execsql_test 39.1 {
  CREATE TABLE t1(a PRIMARY KEY, b);







>
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>

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do_execsql_test 38.2 {
  CREATE VIEW v1 AS SELECT a, b FROM t1;
  CREATE TRIGGER tr1 INSTEAD OF DELETE ON v1 BEGIN
    INSERT INTO log VALUES(old.b, old.a);
  END;
}
do_execsql_test 38.3 {
  SELECT * FROM v1;
} {3 4}
do_execsql_test 38.4 {
  DELETE FROM v1 WHERE a = 3;
} 
do_execsql_test 38.5 {
  SELECT * FROM log;
} {4 3}

#-------------------------------------------------------------------------
reset_db
do_execsql_test 39.1 {
  CREATE TABLE t1(a PRIMARY KEY, b);
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  CREATE INDEX joinme_id_int_idx on joinme(id_int);
}

do_catchsql_test 70.2 {
  select * from maintable as m inner join
    joinme as j indexed by joinme_id_text_idx
    on ( m.id  = j.id_int)
} {1 {cannot use index: joinme_id_text_idx}}

do_catchsql_test 70.3 {
  select * from maintable, joinme INDEXED by joinme_id_text_idx
} {1 {cannot use index: joinme_id_text_idx}}

#-------------------------------------------------------------------------
# This is testing that the "phantom" runs feature works.
#
# UPDATE: Said feature was dropped early in development. But the test 
# remains valid.
reset_db







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  CREATE INDEX joinme_id_int_idx on joinme(id_int);
}

do_catchsql_test 70.2 {
  select * from maintable as m inner join
    joinme as j indexed by joinme_id_text_idx
    on ( m.id  = j.id_int)
} {1 {no query solution}}

do_catchsql_test 70.3 {
  select * from maintable, joinme INDEXED by joinme_id_text_idx
} {1 {no query solution}}

#-------------------------------------------------------------------------
# This is testing that the "phantom" runs feature works.
#
# UPDATE: Said feature was dropped early in development. But the test 
# remains valid.
reset_db
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  INSERT INTO t1(x,y) VALUES(2,CAST(x'02' AS TEXT));
  CREATE TABLE t3(x INT, y COLLATE NOCASE);
  INSERT INTO t3 SELECT x, 'abc' || y || 'xyz' FROM t1;
  CREATE INDEX i3 ON t3(y);
  SELECT x FROM t3 WHERE y LIKE 'abcX%';
} {}

















































finish_test








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  INSERT INTO t1(x,y) VALUES(2,CAST(x'02' AS TEXT));
  CREATE TABLE t3(x INT, y COLLATE NOCASE);
  INSERT INTO t3 SELECT x, 'abc' || y || 'xyz' FROM t1;
  CREATE INDEX i3 ON t3(y);
  SELECT x FROM t3 WHERE y LIKE 'abcX%';
} {}

#-------------------------------------------------------------------------
reset_db
do_execsql_test 86.0 { 
  SELECT * FROM sqlite_master;
} {}
do_execsql_test 86.1 { 
  CREATE TABLE t1(a PRIMARY KEY, b);
}
do_execsql_test 86.2 { 
  INSERT INTO t1 VALUES(1, 'one');
}
do_execsql_test 86.3 { 
  SELECT * FROM t1;
} {1 one}
do_execsql_test 86.4 { 
  SELECT * FROM t1 WHERE a = 1;
} {1 one}

#-------------------------------------------------------------------------
reset_db
do_execsql_test 87.1 {
  CREATE TABLE t6(a INTEGER PRIMARY KEY, b TEXT);
  CREATE INDEX t6i1 ON t6(b);
} {}
do_eqp_test 87.2 {
  SELECT * FROM t6 ORDER BY b, a;
} {0 0 0 {SCAN TABLE t6 USING INDEX t6i1}}

#-------------------------------------------------------------------------
reset_db
do_execsql_test 88.1 {
  CREATE TABLE t8(a INTEGER PRIMARY KEY, b TEXT);
  CREATE UNIQUE INDEX t8i ON t8(b);
}
do_eqp_test 88.2 {
  SELECT * FROM t8 x ORDER BY x.b, x.a, x.b||x.a
} {0 0 0 {SCAN TABLE t8 AS x USING INDEX t8i}}

#-------------------------------------------------------------------------
reset_db
do_execsql_test 89.1 {
  CREATE TABLE t1(a COLLATE NOCASE);
  CREATE INDEX i1 ON t1(a);
}
do_eqp_test 89.2 {
  SELECT * FROM t1 ORDER BY a;
} {0 0 0 {SCAN TABLE t1 USING INDEX i1}}

finish_test

Changes to test/subquery.test.

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  execsql {
    CREATE INDEX t4i ON t4(x);
    SELECT * FROM t4 WHERE x IN (SELECT a FROM t3);
  }
} {10.0}
do_test subquery-2.5.3.2 {
  # Verify that the t4i index was not used in the previous query
  set ::sqlite_query_plan



} {t4 {}}
do_test subquery-2.5.4 {
  execsql {
    DROP TABLE t3;
    DROP TABLE t4;
  }
} {}








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  execsql {
    CREATE INDEX t4i ON t4(x);
    SELECT * FROM t4 WHERE x IN (SELECT a FROM t3);
  }
} {10.0}
do_test subquery-2.5.3.2 {
  # Verify that the t4i index was not used in the previous query
  execsql {
    EXPLAIN QUERY PLAN
    SELECT * FROM t4 WHERE x IN (SELECT a FROM t3);
  }
} {/SCAN TABLE t4 /}
do_test subquery-2.5.4 {
  execsql {
    DROP TABLE t3;
    DROP TABLE t4;
  }
} {}

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  }
} {1 one 2 two}
do_test subquery-3.3.5 {
  execsql {
    SELECT a, (SELECT count(*) FROM t2 WHERE a=c) FROM t1;
  }
} {1 1 2 1}


#------------------------------------------------------------------
# These tests - subquery-4.* - use the TCL statement cache to try 
# and expose bugs to do with re-using statements that have been 
# passed to sqlite4_reset().
#
# One problem was that VDBE memory cells were not being initialised
# to NULL on the second and subsequent executions.
#
do_test subquery-4.1.1 {
  execsql {
    SELECT (SELECT a FROM t1);
  }
} {1}







>






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  }
} {1 one 2 two}
do_test subquery-3.3.5 {
  execsql {
    SELECT a, (SELECT count(*) FROM t2 WHERE a=c) FROM t1;
  }
} {1 1 2 1}


#------------------------------------------------------------------
# These tests - subquery-4.* - use the TCL statement cache to try 
# and expose bugs to do with re-using statements that have been 
# passed to sqlite4_reset().
#
# One problem was that VDBE memory cells were not being initialized
# to NULL on the second and subsequent executions.
#
do_test subquery-4.1.1 {
  execsql {
    SELECT (SELECT a FROM t1);
  }
} {1}

Changes to test/test_main.c.

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  Tcl_Interp *interp;
  Tcl_Obj *pNeeded;
  Tcl_Obj *pDel;
};
typedef struct TestNeededX TestNeededX;

static void testCollationNeeded(void *pCtx, sqlite4 *db, const char *zReq){
  TestNeededX *p = (TestCollationX *)pCtx;
  Tcl_Obj *pScript;
  int rc;

  pScript = Tcl_DuplicateObj(p->pNeeded);
  Tcl_IncrRefCount(pScript);
  Tcl_ListObjAppendElement(0, pScript, Tcl_NewStringObj(zReq, -1));
  rc = Tcl_EvalObjEx(p->interp, pScript, TCL_EVAL_DIRECT|TCL_EVAL_GLOBAL);







|







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  Tcl_Interp *interp;
  Tcl_Obj *pNeeded;
  Tcl_Obj *pDel;
};
typedef struct TestNeededX TestNeededX;

static void testCollationNeeded(void *pCtx, sqlite4 *db, const char *zReq){
  TestNeededX *p = (TestNeededX *)pCtx;
  Tcl_Obj *pScript;
  int rc;

  pScript = Tcl_DuplicateObj(p->pNeeded);
  Tcl_IncrRefCount(pScript);
  Tcl_ListObjAppendElement(0, pScript, Tcl_NewStringObj(zReq, -1));
  rc = Tcl_EvalObjEx(p->interp, pScript, TCL_EVAL_DIRECT|TCL_EVAL_GLOBAL);
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  sqlite4_stmt *pStmt;
  int col;
  Tcl_Obj *pRet;
  const void *zName16;
  const void *(*xFunc)(sqlite4_stmt*, int, int*);
  int dummy;

  xFunc = (const void *(*)(sqlite4_stmt*, int))clientData;
  if( objc!=3 ){
    Tcl_AppendResult(interp, "wrong # args: should be \"",
       Tcl_GetString(objv[0]), " STMT column", 0);
    return TCL_ERROR;
  }

  if( getStmtPointer(interp, Tcl_GetString(objv[1]), &pStmt) ) return TCL_ERROR;







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  sqlite4_stmt *pStmt;
  int col;
  Tcl_Obj *pRet;
  const void *zName16;
  const void *(*xFunc)(sqlite4_stmt*, int, int*);
  int dummy;

  xFunc = (const void *(*)(sqlite4_stmt*, int, int*))clientData;
  if( objc!=3 ){
    Tcl_AppendResult(interp, "wrong # args: should be \"",
       Tcl_GetString(objv[0]), " STMT column", 0);
    return TCL_ERROR;
  }

  if( getStmtPointer(interp, Tcl_GetString(objv[1]), &pStmt) ) return TCL_ERROR;
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  extern int sqlite4_os_type;
#endif
#ifdef SQLITE4_DEBUG
  extern int sqlite4WhereTrace;
  extern int sqlite4OSTrace;
#endif
#ifdef SQLITE4_TEST
  extern char sqlite4_query_plan[];
  static char *query_plan = sqlite4_query_plan;
#ifdef SQLITE4_ENABLE_FTS3
  extern int sqlite4_fts3_enable_parentheses;
#endif
#endif

  for(i=0; i<sizeof(aCmd)/sizeof(aCmd[0]); i++){
    Tcl_CreateCommand(interp, aCmd[i].zName, aCmd[i].xProc, 0, 0);







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4317
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  extern int sqlite4_os_type;
#endif
#ifdef SQLITE4_DEBUG
  extern int sqlite4WhereTrace;
  extern int sqlite4OSTrace;
#endif
#ifdef SQLITE4_TEST


#ifdef SQLITE4_ENABLE_FTS3
  extern int sqlite4_fts3_enable_parentheses;
#endif
#endif

  for(i=0; i<sizeof(aCmd)/sizeof(aCmd[0]); i++){
    Tcl_CreateCommand(interp, aCmd[i].zName, aCmd[i].xProc, 0, 0);
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#endif
  Tcl_LinkVar(interp, "sqlite4_xferopt_count",
      (char*)&sqlite4_xferopt_count, TCL_LINK_INT);
#if SQLITE4_OS_WIN
  Tcl_LinkVar(interp, "sqlite_os_type",
      (char*)&sqlite4_os_type, TCL_LINK_INT);
#endif
#ifdef SQLITE4_TEST
  Tcl_LinkVar(interp, "sqlite_query_plan",
      (char*)&query_plan, TCL_LINK_STRING|TCL_LINK_READ_ONLY);
#endif
#ifdef SQLITE4_DEBUG
  Tcl_LinkVar(interp, "sqlite_where_trace",
      (char*)&sqlite4WhereTrace, TCL_LINK_INT);
#endif
  Tcl_LinkVar(interp, "sqlite_static_bind_value",
      (char*)&sqlite_static_bind_value, TCL_LINK_STRING);
  Tcl_LinkVar(interp, "sqlite_static_bind_nbyte",







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#endif
  Tcl_LinkVar(interp, "sqlite4_xferopt_count",
      (char*)&sqlite4_xferopt_count, TCL_LINK_INT);
#if SQLITE4_OS_WIN
  Tcl_LinkVar(interp, "sqlite_os_type",
      (char*)&sqlite4_os_type, TCL_LINK_INT);
#endif




#ifdef SQLITE4_DEBUG
  Tcl_LinkVar(interp, "sqlite_where_trace",
      (char*)&sqlite4WhereTrace, TCL_LINK_INT);
#endif
  Tcl_LinkVar(interp, "sqlite_static_bind_value",
      (char*)&sqlite_static_bind_value, TCL_LINK_STRING);
  Tcl_LinkVar(interp, "sqlite_static_bind_nbyte",

Changes to test/test_mem.c.

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#include <stdio.h>
#include <assert.h>
#include <string.h>

#include "sqliteInt.h"
#include "testInt.h"

#define MIN(x,y) ((x)<(y) ? (x) : (y))

#if defined(__GLIBC__)
  extern int backtrace(void**,int);
  extern void backtrace_symbols_fd(void*const*,int,int);
# define TM_BACKTRACE 12
#else
# define backtrace(A,B) 1
# define backtrace_symbols_fd(A,B,C)







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#include <stdio.h>
#include <assert.h>
#include <string.h>

#include "sqliteInt.h"
#include "testInt.h"



#if defined(__GLIBC__)
  extern int backtrace(void**,int);
  extern void backtrace_symbols_fd(void*const*,int,int);
# define TM_BACKTRACE 12
#else
# define backtrace(A,B) 1
# define backtrace_symbols_fd(A,B,C)

Changes to test/tester.tcl.

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  if {![info exists ::G(match)] || [string match $::G(match) $name]} {
    if {[catch {uplevel #0 "$cmd;\n"} result]} {
      puts "\nError: $result"
      fail_test $name
    } else {
      if {[regexp {^~?/.*/$} $expected]} {



        if {[string index $expected 0]=="~"} {
          set re [string map {# {[-0-9.]+}} [string range $expected 2 end-1]]
          set ok [expr {![regexp $re $result]}]
        } else {
          set re [string map {# {[-0-9.]+}} [string range $expected 1 end-1]]
          set ok [regexp $re $result]










        }
      } else {
        set ok [expr {[string compare $result $expected]==0}]
      }
      if {!$ok} {
        # if {![info exists ::testprefix] || $::testprefix eq ""} {
        #   error "no test prefix"







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  if {![info exists ::G(match)] || [string match $::G(match) $name]} {
    if {[catch {uplevel #0 "$cmd;\n"} result]} {
      puts "\nError: $result"
      fail_test $name
    } else {
      if {[regexp {^~?/.*/$} $expected]} {
        # "expected" is of the form "/PATTERN/" then the result if correct if
        # regular expression PATTERN matches the result.  "~/PATTERN/" means
        # the regular expression must not match.
        if {[string index $expected 0]=="~"} {
          set re [string map {# {[-0-9.]+}} [string range $expected 2 end-1]]
          set ok [expr {![regexp $re $result]}]
        } else {
          set re [string map {# {[-0-9.]+}} [string range $expected 1 end-1]]
          set ok [regexp $re $result]
        }
      } elseif {[regexp {^~?\*.*\*$} $expected]} {
        # "expected" is of the form "*GLOB*" then the result if correct if
        # glob pattern GLOB matches the result.  "~/GLOB/" means
        # the glob must not match.
        if {[string index $expected 0]=="~"} {
          set e [string range $expected 1 end]
          set ok [expr {![string match $e $result]}]
        } else {
          set ok [string match $expected $result]
        }
      } else {
        set ok [expr {[string compare $result $expected]==0}]
      }
      if {!$ok} {
        # if {![info exists ::testprefix] || $::testprefix eq ""} {
        #   error "no test prefix"

Changes to test/tkt3442.test.

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# These tests perform an EXPLAIN QUERY PLAN on both versions of the 
# SELECT referenced in ticket #3442 (both '5000' and "5000") 
# and verify that the query plan is the same.
#
ifcapable explain {
  do_test tkt3442-1.2 {
    EQP { SELECT node FROM listhash WHERE id='5000' LIMIT 1; }
  } {0 0 0 {SEARCH TABLE listhash USING INDEX ididx (id=?) (~1 rows)}}
}


# Some extra tests testing other permutations of 5000.
#
ifcapable explain {
  do_test tkt3442-1.4 {
    EQP { SELECT node FROM listhash WHERE id=5000 LIMIT 1; }
  } {0 0 0 {SEARCH TABLE listhash USING INDEX ididx (id=?) (~1 rows)}}
}
do_test tkt3442-1.5 {
  catchsql {
    SELECT node FROM listhash WHERE id=[5000] LIMIT 1;
  }
} {1 {no such column: 5000}}








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# These tests perform an EXPLAIN QUERY PLAN on both versions of the 
# SELECT referenced in ticket #3442 (both '5000' and "5000") 
# and verify that the query plan is the same.
#
ifcapable explain {
  do_test tkt3442-1.2 {
    EQP { SELECT node FROM listhash WHERE id='5000' LIMIT 1; }
  } {0 0 0 {SEARCH TABLE listhash USING INDEX ididx (id=?)}}
}


# Some extra tests testing other permutations of 5000.
#
ifcapable explain {
  do_test tkt3442-1.4 {
    EQP { SELECT node FROM listhash WHERE id=5000 LIMIT 1; }
  } {0 0 0 {SEARCH TABLE listhash USING INDEX ididx (id=?)}}
}
do_test tkt3442-1.5 {
  catchsql {
    SELECT node FROM listhash WHERE id=[5000] LIMIT 1;
  }
} {1 {no such column: 5000}}

Changes to test/where.test.

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153
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proc count sql {
  kvwrap reset
  set res [execsql $sql]
  #puts "sql={$sql} seek=[kvwrap seek] step=[kvwrap step]"
  return [concat $res [expr [kvwrap step] + [kvwrap seek]]]
}

# Verify that queries use an index.  We are using the special variable
# "sqlite_search_count" which tallys the number of executions of MoveTo
# and Next operators in the VDBE.  By verifing that the search count is
# small we can be assured that indices are being used properly.
#
do_test where-1.1.1 {
  count {SELECT x, y, w FROM t1 WHERE w=10}
} {3 121 10 3}
do_test where-1.1.2 {
  set sqlite_query_plan
} {t1 i1w}
do_test where-1.1.3 {
  db status step
} {0}
do_test where-1.1.4 {
  db eval {SELECT x, y, w FROM t1 WHERE +w=10}
} {3 121 10}
do_test where-1.1.5 {
  db status step
} {99}
do_test where-1.1.6 {
  set sqlite_query_plan
} {t1 {}}
do_test where-1.1.7 {
  count {SELECT x, y, w AS abc FROM t1 WHERE abc=10}
} {3 121 10 3}
do_test where-1.1.8 {
  set sqlite_query_plan
} {t1 i1w}
do_test where-1.1.9 {
  db status step
} {0}
do_test where-1.2.1 {
  count {SELECT x, y, w FROM t1 WHERE w=11}
} {3 144 11 3}
do_test where-1.2.2 {
  count {SELECT x, y, w AS abc FROM t1 WHERE abc=11}
} {3 144 11 3}
do_test where-1.3.1 {
  count {SELECT x, y, w AS abc FROM t1 WHERE 11=w}
} {3 144 11 3}
do_test where-1.3.2 {
  count {SELECT x, y, w AS abc FROM t1 WHERE 11=abc}
} {3 144 11 3}
do_test where-1.4.1 {
  count {SELECT w, x, y FROM t1 WHERE 11=w AND x>2}
} {11 3 144 3}
do_test where-1.4.2 {
  set sqlite_query_plan
} {t1 i1w}
do_test where-1.4.3 {
  count {SELECT w AS a, x AS b, y FROM t1 WHERE 11=a AND b>2}
} {11 3 144 3}
do_test where-1.4.4 {
  set sqlite_query_plan
} {t1 i1w}
do_test where-1.5 {
  count {SELECT x, y FROM t1 WHERE y<200 AND w=11 AND x>2}
} {3 144 3}
do_test where-1.5.2 {
  set sqlite_query_plan
} {t1 i1w}
do_test where-1.6 {
  count {SELECT x, y FROM t1 WHERE y<200 AND x>2 AND w=11}
} {3 144 3}
do_test where-1.7 {
  count {SELECT x, y FROM t1 WHERE w=11 AND y<200 AND x>2}
} {3 144 3}
do_test where-1.8 {
  count {SELECT x, y FROM t1 WHERE w>10 AND y=144 AND x=3}
} {3 144 3}
do_test where-1.8.2 {
  set sqlite_query_plan
} {t1 i1xy}
do_test where-1.8.3 {
  count {SELECT x, y FROM t1 WHERE y=144 AND x=3}
  set sqlite_query_plan
} {t1 i1xy}
do_test where-1.9 {
  count {SELECT x, y FROM t1 WHERE y=144 AND w>10 AND x=3}
} {3 144 3}
do_test where-1.10 {
  count {SELECT x, y FROM t1 WHERE x=3 AND w>=10 AND y=121}
} {3 121 3}
do_test where-1.11 {
  count {SELECT x, y FROM t1 WHERE x=3 AND y=100 AND w<10}
} {3 100 3}


# New for SQLite version 2.1: Verify that that inequality constraints
# are used correctly.
#
do_test where-1.12 {
  count {SELECT w FROM t1 WHERE x=3 AND y<100}
} {8 3}







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proc count sql {
  kvwrap reset
  set res [execsql $sql]
  #puts "sql={$sql} seek=[kvwrap seek] step=[kvwrap step]"
  return [concat $res [expr [kvwrap step] + [kvwrap seek]]]
}

# Verify that queries use an index. By verifing that the KVWrap layer

# xNext/xPrev/xSeek count is small we can be assured that indices are 
# being used properly.
#
do_test where-1.1.1 {
  count {SELECT x, y, w FROM t1 WHERE w=10}
} {3 121 10 3}
do_eqp_test where-1.1.2 {
  SELECT x, y, w FROM t1 WHERE w=10
} {*SEARCH TABLE t1 USING INDEX i1w (w=?)*}
do_test where-1.1.3 {
  db status step
} {0}
do_test where-1.1.4 {
  db eval {SELECT x, y, w FROM t1 WHERE +w=10}
} {3 121 10}
do_test where-1.1.5 {
  db status step
} {99}
do_eqp_test where-1.1.6 {
  SELECT x, y, w FROM t1 WHERE +w=10
} {*SCAN TABLE t1*}
do_test where-1.1.7 {
  count {SELECT x, y, w AS abc FROM t1 WHERE abc=10}
} {3 121 10 3}
do_eqp_test where-1.1.8 {
  SELECT x, y, w AS abc FROM t1 WHERE abc=10
} {*SEARCH TABLE t1 USING INDEX i1w (w=?)*}
do_test where-1.1.9 {
  db status step
} {0}
do_test where-1.2.1 {
  count {SELECT x, y, w FROM t1 WHERE w=11}
} {3 144 11 3}
do_test where-1.2.2 {
  count {SELECT x, y, w AS abc FROM t1 WHERE abc=11}
} {3 144 11 3}
do_test where-1.3.1 {
  count {SELECT x, y, w AS abc FROM t1 WHERE 11=w}
} {3 144 11 3}
do_test where-1.3.2 {
  count {SELECT x, y, w AS abc FROM t1 WHERE 11=abc}
} {3 144 11 3}
do_test where-1.4.1 {
  count {SELECT w, x, y FROM t1 WHERE 11=w AND x>2}
} {11 3 144 3}
do_eqp_test where-1.4.2 {
  SELECT w, x, y FROM t1 WHERE 11=w AND x>2
} {*SEARCH TABLE t1 USING INDEX i1w (w=?)*}
do_test where-1.4.3 {
  count {SELECT w AS a, x AS b, y FROM t1 WHERE 11=a AND b>2}
} {11 3 144 3}
do_eqp_test where-1.4.4 {
  SELECT w AS a, x AS b, y FROM t1 WHERE 11=a AND b>2
} {*SEARCH TABLE t1 USING INDEX i1w (w=?)*}
do_test where-1.5 {
  count {SELECT x, y FROM t1 WHERE y<200 AND w=11 AND x>2}
} {3 144 3}
do_eqp_test where-1.5.2 {
  SELECT x, y FROM t1 WHERE y<200 AND w=11 AND x>2
} {*SEARCH TABLE t1 USING INDEX i1w (w=?)*}
do_test where-1.6 {
  count {SELECT x, y FROM t1 WHERE y<200 AND x>2 AND w=11}
} {3 144 3}
do_test where-1.7 {
  count {SELECT x, y FROM t1 WHERE w=11 AND y<200 AND x>2}
} {3 144 3}
do_test where-1.8 {
  count {SELECT x, y FROM t1 WHERE w>10 AND y=144 AND x=3}
} {3 144 3}
do_eqp_test where-1.8.2 {
  SELECT x, y FROM t1 WHERE w>10 AND y=144 AND x=3
} {*SEARCH TABLE t1 USING INDEX i1xy (x=? AND y=?)*}
do_eqp_test where-1.8.3 {
  SELECT x, y FROM t1 WHERE y=144 AND x=3

} {*SEARCH TABLE t1 USING INDEX i1xy (x=? AND y=?)*}
do_test where-1.9 {
  count {SELECT x, y FROM t1 WHERE y=144 AND w>10 AND x=3}
} {3 144 3}
do_test where-1.10 {
  count {SELECT x, y FROM t1 WHERE x=3 AND w>=10 AND y=121}
} {3 121 3}
do_test where-1.11 {
  count {SELECT x, y FROM t1 WHERE x=3 AND y=100 AND w<10}
} {3 100 3}


# New for SQLite version 2.1: Verify that that inequality constraints
# are used correctly.
#
do_test where-1.12 {
  count {SELECT w FROM t1 WHERE x=3 AND y<100}
} {8 3}
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do_test where-6.6 {
  cksort {
    SELECT * FROM t3 WHERE a>0 ORDER BY a LIMIT 3
  }
} {1 100 4 2 99 9 3 98 16 nosort}

do_test where-6.7 {
  # UPDATE: src4 does a sort here. It picks a different index because it
  # does not support the covering index optimization.
  cksort {
    SELECT * FROM t3 WHERE b>0 ORDER BY a LIMIT 3
  }
} {1 100 4 2 99 9 3 98 16 sort}

ifcapable subquery {
  do_test where-6.8 {
    cksort {
      SELECT * FROM t3 WHERE a IN (3,5,7,1,9,4,2) ORDER BY a LIMIT 3
    }
  } {1 100 4 2 99 9 3 98 16 sort}
}
do_test where-6.9.1 {
  cksort {
    SELECT * FROM t3 WHERE a=1 AND c>0 ORDER BY a LIMIT 3
  }
} {1 100 4 nosort}
do_test where-6.9.1.1 {







<
<



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do_test where-6.6 {
  cksort {
    SELECT * FROM t3 WHERE a>0 ORDER BY a LIMIT 3
  }
} {1 100 4 2 99 9 3 98 16 nosort}

do_test where-6.7 {


  cksort {
    SELECT * FROM t3 WHERE b>0 ORDER BY a LIMIT 3
  }
} {1 100 4 2 99 9 3 98 16 nosort}

ifcapable subquery {
  do_test where-6.8 {
    cksort {
      SELECT * FROM t3 WHERE a IN (3,5,7,1,9,4,2) ORDER BY a LIMIT 3
    }
  } {1 100 4 2 99 9 3 98 16 nosort}
}
do_test where-6.9.1 {
  cksort {
    SELECT * FROM t3 WHERE a=1 AND c>0 ORDER BY a LIMIT 3
  }
} {1 100 4 nosort}
do_test where-6.9.1.1 {
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    CREATE TABLE t8(a INTEGER PRIMARY KEY, b TEXT UNIQUE);
    INSERT INTO t8 VALUES(1,'one');
    INSERT INTO t8 VALUES(4,'four');
  }
  cksort {
    SELECT x.a || '/' || y.a FROM t8 x, t8 y ORDER BY x.a, y.b
  } 
} {1/4 1/1 4/4 4/1 sort}
do_test where-14.2 {
  cksort {
    SELECT x.a || '/' || y.a FROM t8 x, t8 y ORDER BY x.a, y.b DESC
  } 
} {1/1 1/4 4/1 4/4 sort}
do_test where-14.3 {
  cksort {
    SELECT x.a || '/' || y.a FROM t8 x, t8 y ORDER BY x.a, x.b
  } 
} {1/1 1/4 4/1 4/4 nosort}
do_test where-14.4 {
  cksort {







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    CREATE TABLE t8(a INTEGER PRIMARY KEY, b TEXT UNIQUE);
    INSERT INTO t8 VALUES(1,'one');
    INSERT INTO t8 VALUES(4,'four');
  }
  cksort {
    SELECT x.a || '/' || y.a FROM t8 x, t8 y ORDER BY x.a, y.b
  } 
} {1/4 1/1 4/4 4/1 nosort}
do_test where-14.2 {
  cksort {
    SELECT x.a || '/' || y.a FROM t8 x, t8 y ORDER BY x.a, y.b DESC
  } 
} {1/1 1/4 4/1 4/4 nosort}
do_test where-14.3 {
  cksort {
    SELECT x.a || '/' || y.a FROM t8 x, t8 y ORDER BY x.a, x.b
  } 
} {1/1 1/4 4/1 4/4 nosort}
do_test where-14.4 {
  cksort {

Changes to test/where7.test.

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  );
  CREATE INDEX t302_c3 on t302(c3);
  CREATE INDEX t302_c8_c3 on t302(c8, c3);
  CREATE INDEX t302_c5 on t302(c5);
  
  EXPLAIN QUERY PLAN
  SELECT t302.c1 
    FROM t302 JOIN t301 ON t302.c8 = t301.c8
    WHERE t302.c2 = 19571
      AND t302.c3 > 1287603136
      AND (t301.c4 = 1407449685622784
           OR t301.c8 = 1407424651264000)
   ORDER BY t302.c5 LIMIT 200;
} {
  0 0 1 {SEARCH TABLE t301 USING INDEX t301_c4 (c4=?) (~5 rows)} 
  0 0 1 {SEARCH TABLE t301 USING PRIMARY KEY (c8=?) (~1 rows)} 
  0 1 0 {SEARCH TABLE t302 USING INDEX t302_c8_c3 (c8=? AND c3>?) (~2 rows)} 
  0 0 0 {USE TEMP B-TREE FOR ORDER BY}
}

finish_test







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  );
  CREATE INDEX t302_c3 on t302(c3);
  CREATE INDEX t302_c8_c3 on t302(c8, c3);
  CREATE INDEX t302_c5 on t302(c5);
  
  EXPLAIN QUERY PLAN
  SELECT t302.c1 
    FROM t302 JOIN t301 ON t302.c8 = +t301.c8
    WHERE t302.c2 = 19571
      AND t302.c3 > 1287603136
      AND (t301.c4 = 1407449685622784
           OR t301.c8 = 1407424651264000)
   ORDER BY t302.c5 LIMIT 200;
} {
  0 0 1 {SEARCH TABLE t301 USING INDEX t301_c4 (c4=?)}
  0 0 1 {SEARCH TABLE t301 USING INDEX t301 (c8=?)}
  0 1 0 {SEARCH TABLE t302 USING INDEX t302_c8_c3 (c8=? AND c3>?)}
  0 0 0 {USE TEMP B-TREE FOR ORDER BY}
}

finish_test

Changes to test/where8.test.

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  # The "OR c = 'IX'" term forces a linear scan.
  execsql_status2 {
    SELECT a, d 
    FROM t1, t2 
    WHERE (a = 2 OR b = 'three' OR c = 'IX') AND (d = a OR e = 'sixteen')
    ORDER BY t1.rowid
  }
} {2 2 2 4 3 3 3 4 9 9 9 4 0 0 seek=13 step=16}
do_test where8-3.10 {
  execsql_status {
    SELECT d FROM t2 WHERE e IS NULL OR e = 'four'
  }
} {1 3 5 10 2 0 0}

do_test where8-3.11 {
  execsql_status {
    SELECT a, d FROM t1, t2 WHERE (a=d OR b=e) AND a<5 ORDER BY a
  }
} {1 1 2 2 3 3 4 2 4 4 0 0}
do_test where8-3.12 {
  execsql_status {
    SELECT a, d FROM t1, t2 WHERE (a=d OR b=e) AND +a<5 ORDER BY a
  }
} {1 1 2 2 3 3 4 2 4 4 0 0}
do_test where8-3.13 {
  execsql_status {
    SELECT a, d FROM t1, t2 WHERE (a=d OR b=e) AND +a<5
  }
} {1 1 2 2 3 3 4 2 4 4 9 0}

do_test where8-3.14 {







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  # The "OR c = 'IX'" term forces a linear scan.
  execsql_status2 {
    SELECT a, d 
    FROM t1, t2 
    WHERE (a = 2 OR b = 'three' OR c = 'IX') AND (d = a OR e = 'sixteen')
    ORDER BY t1.rowid
  }
} {2 2 2 4 3 3 3 4 9 9 9 4 9 0 seek=13 step=16}
do_test where8-3.10 {
  execsql_status {
    SELECT d FROM t2 WHERE e IS NULL OR e = 'four'
  }
} {1 3 5 10 2 0 0}

do_test where8-3.11 {
  execsql_status {
    SELECT a, d FROM t1, t2 WHERE (a=d OR b=e) AND a<5 ORDER BY a
  }
} {1 1 2 2 3 3 4 2 4 4 0 0}
do_test where8-3.12 {
  execsql_status {
    SELECT a, d FROM t1, t2 WHERE (a=d OR b=e) AND +a<5 ORDER BY a
  }
} {1 1 2 2 3 3 4 2 4 4 9 0}
do_test where8-3.13 {
  execsql_status {
    SELECT a, d FROM t1, t2 WHERE (a=d OR b=e) AND +a<5
  }
} {1 1 2 2 3 3 4 2 4 4 9 0}

do_test where8-3.14 {