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Overview
Comment:Loop through the elements on the RHS of an IN operator in reverse order when the ORDER BY clauses specifies DESC.
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SHA1: f78395c8896666bb1359b83fbcd58d5e3dbc39d3
User & Date: drh 2013-02-08 18:48:23
Context
2013-02-08
20:39
Make sure the virtual tables that take advantage of IN operators sort the RHS of the IN operator in the correct order according to the ORDER BY clause. check-in: b016b754 user: drh tags: IN-with-ORDERBY
18:48
Loop through the elements on the RHS of an IN operator in reverse order when the ORDER BY clauses specifies DESC. check-in: f78395c8 user: drh tags: IN-with-ORDERBY
16:04
Allow the "a=?1 OR a=?2" to "a IN (?1,?2)" transformation to work on virtual tables again. This was formerly restricted because virtual tables could not optimize IN terms. (See check-in [fad88e71cf195e].) But IN terms are now used by virtual tables (as of check-in [3d65c70343]) so the restriction can now be removed. check-in: a917c1f0 user: drh tags: IN-with-ORDERBY
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Changes to src/sqliteInt.h.

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  int p1, p2;           /* Operands of the opcode used to ends the loop */
  union {               /* Information that depends on plan.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 */

      } *aInLoop;           /* Information about each nested IN operator */
    } in;                 /* Used when plan.wsFlags&WHERE_IN_ABLE */
    Index *pCovidx;       /* Possible covering index for WHERE_MULTI_OR */
  } u;
  double rOptCost;      /* "Optimal" cost for this level */

  /* The following field is really not part of the current level.  But







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  int p1, p2;           /* Operands of the opcode used to ends the loop */
  union {               /* Information that depends on plan.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 plan.wsFlags&WHERE_IN_ABLE */
    Index *pCovidx;       /* Possible covering index for WHERE_MULTI_OR */
  } u;
  double rOptCost;      /* "Optimal" cost for this level */

  /* The following field is really not part of the current level.  But

Changes to src/where.c.

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    /* If X is the column in the index and ORDER BY clause, check to see
    ** if there are any X= or X IS NULL constraints in the WHERE clause. */
    pConstraint = findTerm(p->pWC, base, iColumn, p->notReady,
                           WO_EQ|WO_ISNULL|WO_IN, pIdx);
    if( pConstraint==0 ){
      isEq = 0;
    }else if( (pConstraint->eOperator & WO_IN)!=0 ){
#if 0
      /* Constraints of the form: "X IN ..." cannot be used with an ORDER BY
      ** because we do not know in what order the values on the RHS of the IN
      ** operator will occur. */
      break;
#else
      if( termSortOrder ) break;
      isEq = 0;
#endif
    }else if( (pConstraint->eOperator & WO_ISNULL)!=0 ){
      uniqueNotNull = 0;
      isEq = 1;  /* "X IS NULL" means X has only a single value */
    }else if( pConstraint->prereqRight==0 ){
      isEq = 1;  /* Constraint "X=constant" means X has only a single value */
    }else{
      Expr *pRight = pConstraint->pExpr->pRight;
................................................................................
    iReg = iTarget;
    sqlite3VdbeAddOp2(v, OP_Null, 0, iReg);
#ifndef SQLITE_OMIT_SUBQUERY
  }else{
    int eType;
    int iTab;
    struct InLoop *pIn;


    assert( pX->op==TK_IN );
    iReg = iTarget;
    eType = sqlite3FindInIndex(pParse, pX, 0);
    iTab = pX->iTable;
    sqlite3VdbeAddOp2(v, OP_Rewind, iTab, 0);
    assert( pLevel->plan.wsFlags & WHERE_IN_ABLE );
    if( pLevel->u.in.nIn==0 ){
      pLevel->addrNxt = sqlite3VdbeMakeLabel(v);
    }
    pLevel->u.in.nIn++;
    pLevel->u.in.aInLoop =
       sqlite3DbReallocOrFree(pParse->db, pLevel->u.in.aInLoop,
................................................................................
      pIn += pLevel->u.in.nIn - 1;
      pIn->iCur = iTab;
      if( eType==IN_INDEX_ROWID ){
        pIn->addrInTop = sqlite3VdbeAddOp2(v, OP_Rowid, iTab, iReg);
      }else{
        pIn->addrInTop = sqlite3VdbeAddOp3(v, OP_Column, iTab, 0, iReg);
      }

      sqlite3VdbeAddOp1(v, OP_IsNull, iReg);
    }else{
      pLevel->u.in.nIn = 0;
    }
#endif
  }
  disableTerm(pLevel, pTerm);
................................................................................
    }
    if( pLevel->plan.wsFlags & WHERE_IN_ABLE && pLevel->u.in.nIn>0 ){
      struct InLoop *pIn;
      int j;
      sqlite3VdbeResolveLabel(v, pLevel->addrNxt);
      for(j=pLevel->u.in.nIn, pIn=&pLevel->u.in.aInLoop[j-1]; j>0; j--, pIn--){
        sqlite3VdbeJumpHere(v, pIn->addrInTop+1);
        sqlite3VdbeAddOp2(v, OP_Next, pIn->iCur, pIn->addrInTop);
        sqlite3VdbeJumpHere(v, pIn->addrInTop-1);
      }
      sqlite3DbFree(db, pLevel->u.in.aInLoop);
    }
    sqlite3VdbeResolveLabel(v, pLevel->addrBrk);
    if( pLevel->iLeftJoin ){
      int addr;







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    /* If X is the column in the index and ORDER BY clause, check to see
    ** if there are any X= or X IS NULL constraints in the WHERE clause. */
    pConstraint = findTerm(p->pWC, base, iColumn, p->notReady,
                           WO_EQ|WO_ISNULL|WO_IN, pIdx);
    if( pConstraint==0 ){
      isEq = 0;
    }else if( (pConstraint->eOperator & WO_IN)!=0 ){







      isEq = 0;

    }else if( (pConstraint->eOperator & WO_ISNULL)!=0 ){
      uniqueNotNull = 0;
      isEq = 1;  /* "X IS NULL" means X has only a single value */
    }else if( pConstraint->prereqRight==0 ){
      isEq = 1;  /* Constraint "X=constant" means X has only a single value */
    }else{
      Expr *pRight = pConstraint->pExpr->pRight;
................................................................................
    iReg = iTarget;
    sqlite3VdbeAddOp2(v, OP_Null, 0, iReg);
#ifndef SQLITE_OMIT_SUBQUERY
  }else{
    int eType;
    int iTab;
    struct InLoop *pIn;
    u8 bRev = (pLevel->plan.wsFlags & WHERE_REVERSE)!=0;

    assert( pX->op==TK_IN );
    iReg = iTarget;
    eType = sqlite3FindInIndex(pParse, pX, 0);
    iTab = pX->iTable;
    sqlite3VdbeAddOp2(v, bRev ? OP_Last : OP_Rewind, iTab, 0);
    assert( pLevel->plan.wsFlags & WHERE_IN_ABLE );
    if( pLevel->u.in.nIn==0 ){
      pLevel->addrNxt = sqlite3VdbeMakeLabel(v);
    }
    pLevel->u.in.nIn++;
    pLevel->u.in.aInLoop =
       sqlite3DbReallocOrFree(pParse->db, pLevel->u.in.aInLoop,
................................................................................
      pIn += pLevel->u.in.nIn - 1;
      pIn->iCur = iTab;
      if( eType==IN_INDEX_ROWID ){
        pIn->addrInTop = sqlite3VdbeAddOp2(v, OP_Rowid, iTab, iReg);
      }else{
        pIn->addrInTop = sqlite3VdbeAddOp3(v, OP_Column, iTab, 0, iReg);
      }
      pIn->eEndLoopOp = bRev ? OP_Prev : OP_Next;
      sqlite3VdbeAddOp1(v, OP_IsNull, iReg);
    }else{
      pLevel->u.in.nIn = 0;
    }
#endif
  }
  disableTerm(pLevel, pTerm);
................................................................................
    }
    if( pLevel->plan.wsFlags & WHERE_IN_ABLE && pLevel->u.in.nIn>0 ){
      struct InLoop *pIn;
      int j;
      sqlite3VdbeResolveLabel(v, pLevel->addrNxt);
      for(j=pLevel->u.in.nIn, pIn=&pLevel->u.in.aInLoop[j-1]; j>0; j--, pIn--){
        sqlite3VdbeJumpHere(v, pIn->addrInTop+1);
        sqlite3VdbeAddOp2(v, pIn->eEndLoopOp, pIn->iCur, pIn->addrInTop);
        sqlite3VdbeJumpHere(v, pIn->addrInTop-1);
      }
      sqlite3DbFree(db, pLevel->u.in.aInLoop);
    }
    sqlite3VdbeResolveLabel(v, pLevel->addrBrk);
    if( pLevel->iLeftJoin ){
      int addr;

Changes to test/where.test.

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      SELECT * FROM t1 WHERE w IN (3,2,-1,1,2) order by 1;
    }
  } {1 0 4 2 1 9 3 1 16 13}
  do_test where-5.3d {
    count {
      SELECT * FROM t1 WHERE w IN (-1,1,2,3) order by 1 DESC;
    }
  } {3 1 16 2 1 9 1 0 4 14}
  do_test where-5.4 {
    count {
      SELECT * FROM t1 WHERE w+0 IN (-1,1,2,3) order by 1;
    }
  } {1 0 4 2 1 9 3 1 16 102}
  do_test where-5.5 {
    count {
................................................................................
    }
  } {2 1 9 8}
  do_test where-5.15 {
    count {
      SELECT * FROM t1 WHERE x IN (1,7) AND y IN (9,16) ORDER BY 1;
    }
  } {2 1 9 3 1 16 11}
























}

# This procedure executes the SQL.  Then it checks to see if the OP_Sort
# opcode was executed.  If an OP_Sort did occur, then "sort" is appended
# to the result.  If no OP_Sort happened, then "nosort" is appended.
#
# This procedure is used to check to make sure sorting is or is not
................................................................................
      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-6.8b {
    cksort {
      SELECT * FROM t3 WHERE a IN (3,5,7,1,9,4,2) ORDER BY a DESC LIMIT 3
    }
  } {9 92 100 7 94 64 5 96 36 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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      SELECT * FROM t1 WHERE w IN (3,2,-1,1,2) order by 1;
    }
  } {1 0 4 2 1 9 3 1 16 13}
  do_test where-5.3d {
    count {
      SELECT * FROM t1 WHERE w IN (-1,1,2,3) order by 1 DESC;
    }
  } {3 1 16 2 1 9 1 0 4 12}
  do_test where-5.4 {
    count {
      SELECT * FROM t1 WHERE w+0 IN (-1,1,2,3) order by 1;
    }
  } {1 0 4 2 1 9 3 1 16 102}
  do_test where-5.5 {
    count {
................................................................................
    }
  } {2 1 9 8}
  do_test where-5.15 {
    count {
      SELECT * FROM t1 WHERE x IN (1,7) AND y IN (9,16) ORDER BY 1;
    }
  } {2 1 9 3 1 16 11}
  do_test where-5.100 {
    db eval {
      SELECT w, x, y FROM t1 WHERE x IN (1,5) AND y IN (9,8,3025,1000,3969)
       ORDER BY x, y
    }
  } {2 1 9 54 5 3025 62 5 3969}
  do_test where-5.101 {
    db eval {
      SELECT w, x, y FROM t1 WHERE x IN (1,5) AND y IN (9,8,3025,1000,3969)
       ORDER BY x DESC, y DESC
    }
  } {62 5 3969 54 5 3025 2 1 9}
  do_test where-5.102 {
    db eval {
      SELECT w, x, y FROM t1 WHERE x IN (1,5) AND y IN (9,8,3025,1000,3969)
       ORDER BY x DESC, y
    }
  } {54 5 3025 62 5 3969 2 1 9}
  do_test where-5.103 {
    db eval {
      SELECT w, x, y FROM t1 WHERE x IN (1,5) AND y IN (9,8,3025,1000,3969)
       ORDER BY x, y DESC
    }
  } {2 1 9 62 5 3969 54 5 3025}
}

# This procedure executes the SQL.  Then it checks to see if the OP_Sort
# opcode was executed.  If an OP_Sort did occur, then "sort" is appended
# to the result.  If no OP_Sort happened, then "nosort" is appended.
#
# This procedure is used to check to make sure sorting is or is not
................................................................................
      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-6.8b {
    cksort {
      SELECT * FROM t3 WHERE a IN (3,5,7,1,9,4,2) ORDER BY a DESC LIMIT 3
    }
  } {9 92 100 7 94 64 5 96 36 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 {

Changes to test/where2.test.

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  do_test where2-4.6b {
    queryplan {
      SELECT * FROM t1
       WHERE x IN (1,2,3,4,5,6,7,8)
         AND y IN (10000,10001,10002,10003,10004,10005)
       ORDER BY x DESC
    }
  } {99 6 10000 10006 sort t1 i1xy}
  do_test where2-4.6c {
    queryplan {
      SELECT * FROM t1
       WHERE x IN (1,2,3,4,5,6,7,8)
         AND y IN (10000,10001,10002,10003,10004,10005)
       ORDER BY x, y
    }
................................................................................
      SELECT * FROM t1 WHERE w IN (99) ORDER BY w
    }
  } {99 6 10000 10006 nosort t1 i1w}
  do_test where2-5.2b {
    queryplan {
      SELECT * FROM t1 WHERE w IN (99) ORDER BY w DESC
    }
  } {99 6 10000 10006 sort t1 i1w}
}

# Verify that OR clauses get translated into IN operators.
#
set ::idx {}
ifcapable subquery {set ::idx i1w}
do_test where2-6.1.1 {







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  do_test where2-4.6b {
    queryplan {
      SELECT * FROM t1
       WHERE x IN (1,2,3,4,5,6,7,8)
         AND y IN (10000,10001,10002,10003,10004,10005)
       ORDER BY x DESC
    }
  } {99 6 10000 10006 nosort t1 i1xy}
  do_test where2-4.6c {
    queryplan {
      SELECT * FROM t1
       WHERE x IN (1,2,3,4,5,6,7,8)
         AND y IN (10000,10001,10002,10003,10004,10005)
       ORDER BY x, y
    }
................................................................................
      SELECT * FROM t1 WHERE w IN (99) ORDER BY w
    }
  } {99 6 10000 10006 nosort t1 i1w}
  do_test where2-5.2b {
    queryplan {
      SELECT * FROM t1 WHERE w IN (99) ORDER BY w DESC
    }
  } {99 6 10000 10006 nosort t1 i1w}
}

# Verify that OR clauses get translated into IN operators.
#
set ::idx {}
ifcapable subquery {set ::idx i1w}
do_test where2-6.1.1 {