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Overview
Comment:Fix EXPLAIN QUERY PLAN output for indexed-expressions. Fix another obscure fault in the WHERE term scanner.
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Timelines: family | ancestors | descendants | both | index-expr
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SHA1: 73d361ce9e4d72c943def8b0b3caa227f9199aed
User & Date: drh 2015-08-27 20:33:38.975
Context
2015-08-27
23:42
Fix the OR-optimization so that it always ignores subplans that do not use an index. (check-in: cf452028d1 user: drh tags: index-expr)
20:33
Fix EXPLAIN QUERY PLAN output for indexed-expressions. Fix another obscure fault in the WHERE term scanner. (check-in: 73d361ce9e user: drh tags: index-expr)
19:56
Fix problems in the indexed-expression handling in the optimizer. (check-in: 0337501769 user: drh tags: index-expr)
Changes
Unified Diff Ignore Whitespace Patch
Changes to src/where.c.
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         && pTerm->u.leftColumn==iColumn
         && (iColumn!=(-2)
               || sqlite3ExprCompare(pTerm->pExpr->pLeft,pScan->pIdxExpr,iCur)==0)
         && (pScan->iEquiv<=1 || !ExprHasProperty(pTerm->pExpr, EP_FromJoin))
        ){
          if( (pTerm->eOperator & WO_EQUIV)!=0
           && pScan->nEquiv<ArraySize(pScan->aiCur)

          ){
            int j;
            pX = sqlite3ExprSkipCollate(pTerm->pExpr->pRight);
            assert( pX->op==TK_COLUMN );
            for(j=0; j<pScan->nEquiv; j++){
              if( pScan->aiCur[j]==pX->iTable
               && pScan->aiColumn[j]==pX->iColumn ){
                  break;
              }
            }
            if( j==pScan->nEquiv ){








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         && pTerm->u.leftColumn==iColumn
         && (iColumn!=(-2)
               || sqlite3ExprCompare(pTerm->pExpr->pLeft,pScan->pIdxExpr,iCur)==0)
         && (pScan->iEquiv<=1 || !ExprHasProperty(pTerm->pExpr, EP_FromJoin))
        ){
          if( (pTerm->eOperator & WO_EQUIV)!=0
           && pScan->nEquiv<ArraySize(pScan->aiCur)
           && (pX = sqlite3ExprSkipCollate(pTerm->pExpr->pRight))->op==TK_COLUMN
          ){
            int j;


            for(j=0; j<pScan->nEquiv; j++){
              if( pScan->aiCur[j]==pX->iTable
               && pScan->aiColumn[j]==pX->iColumn ){
                  break;
              }
            }
            if( j==pScan->nEquiv ){
︙︙
Changes to src/wherecode.c.
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  const char *zOp             /* Name of the operator */
){
  if( iTerm ) sqlite3StrAccumAppend(pStr, " AND ", 5);
  sqlite3StrAccumAppendAll(pStr, zColumn);
  sqlite3StrAccumAppend(pStr, zOp, 1);
  sqlite3StrAccumAppend(pStr, "?", 1);
}











/*
** Argument pLevel describes a strategy for scanning table pTab. This 
** function appends text to pStr that describes the subset of table
** rows scanned by the strategy in the form of an SQL expression.
**
** For example, if the query:
**
**   SELECT * FROM t1 WHERE a=1 AND b>2;
**
** is run and there is an index on (a, b), then this function returns a
** string similar to:
**
**   "a=? AND b>?"
*/
static void explainIndexRange(StrAccum *pStr, WhereLoop *pLoop, Table *pTab){
  Index *pIndex = pLoop->u.btree.pIndex;
  u16 nEq = pLoop->u.btree.nEq;
  u16 nSkip = pLoop->nSkip;
  int i, j;
  Column *aCol = pTab->aCol;
  i16 *aiColumn = pIndex->aiColumn;

  if( nEq==0 && (pLoop->wsFlags&(WHERE_BTM_LIMIT|WHERE_TOP_LIMIT))==0 ) return;
  sqlite3StrAccumAppend(pStr, " (", 2);
  for(i=0; i<nEq; i++){
    char *z = aiColumn[i] < 0 ? "rowid" : aCol[aiColumn[i]].zName;
    if( i>=nSkip ){
      explainAppendTerm(pStr, i, z, "=");
    }else{
      if( i ) sqlite3StrAccumAppend(pStr, " AND ", 5);
      sqlite3XPrintf(pStr, 0, "ANY(%s)", z);
    }
  }

  j = i;
  if( pLoop->wsFlags&WHERE_BTM_LIMIT ){
    char *z = aiColumn[j] < 0 ? "rowid" : aCol[aiColumn[j]].zName;
    explainAppendTerm(pStr, i++, z, ">");
  }
  if( pLoop->wsFlags&WHERE_TOP_LIMIT ){
    char *z = aiColumn[j] < 0 ? "rowid" : aCol[aiColumn[j]].zName;
    explainAppendTerm(pStr, i, z, "<");
  }
  sqlite3StrAccumAppend(pStr, ")", 1);
}

/*
** This function is a no-op unless currently processing an EXPLAIN QUERY PLAN








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  const char *zOp             /* Name of the operator */
){
  if( iTerm ) sqlite3StrAccumAppend(pStr, " AND ", 5);
  sqlite3StrAccumAppendAll(pStr, zColumn);
  sqlite3StrAccumAppend(pStr, zOp, 1);
  sqlite3StrAccumAppend(pStr, "?", 1);
}

/*
** Return the name of the i-th column of the pIdx index.
*/
static const char *explainIndexColumnName(Index *pIdx, int i){
  i = pIdx->aiColumn[i];
  if( i==(-2) ) return "<expr>";
  if( i==(-1) ) return "rowid";
  return pIdx->pTable->aCol[i].zName;
}

/*
** Argument pLevel describes a strategy for scanning table pTab. This 
** function appends text to pStr that describes the subset of table
** rows scanned by the strategy in the form of an SQL expression.
**
** For example, if the query:
**
**   SELECT * FROM t1 WHERE a=1 AND b>2;
**
** is run and there is an index on (a, b), then this function returns a
** string similar to:
**
**   "a=? AND b>?"
*/
static void explainIndexRange(StrAccum *pStr, WhereLoop *pLoop, Table *pTab){
  Index *pIndex = pLoop->u.btree.pIndex;
  u16 nEq = pLoop->u.btree.nEq;
  u16 nSkip = pLoop->nSkip;
  int i, j;



  if( nEq==0 && (pLoop->wsFlags&(WHERE_BTM_LIMIT|WHERE_TOP_LIMIT))==0 ) return;
  sqlite3StrAccumAppend(pStr, " (", 2);
  for(i=0; i<nEq; i++){
    const char *z = explainIndexColumnName(pIndex, i);
    if( i>=nSkip ){
      explainAppendTerm(pStr, i, z, "=");
    }else{
      if( i ) sqlite3StrAccumAppend(pStr, " AND ", 5);
      sqlite3XPrintf(pStr, 0, "ANY(%s)", z);
    }
  }

  j = i;
  if( pLoop->wsFlags&WHERE_BTM_LIMIT ){
    const char *z = explainIndexColumnName(pIndex, i);
    explainAppendTerm(pStr, i++, z, ">");
  }
  if( pLoop->wsFlags&WHERE_TOP_LIMIT ){
    const char *z = explainIndexColumnName(pIndex, j);
    explainAppendTerm(pStr, i, z, "<");
  }
  sqlite3StrAccumAppend(pStr, ")", 1);
}

/*
** This function is a no-op unless currently processing an EXPLAIN QUERY PLAN
︙︙