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Fix a problem with estimating the number of rows visited by a query that uses a multi-column IN(SELECT...) constraint.

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FossilOrigin-Name: 3c2f908f5b7312570cfa74afcf4252a857cb5237
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dan
2016-08-03 18:00:49 +00:00
parent 2c628ea9d9
commit 3d1fb1dd75
4 changed files with 48 additions and 11 deletions
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15
src/where.c
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@@ -2376,14 +2376,23 @@ static int whereLoopAddBtreeIndex(
pNew->wsFlags |= WHERE_COLUMN_IN;
if( ExprHasProperty(pExpr, EP_xIsSelect) ){
/* "x IN (SELECT ...)": TUNING: the SELECT returns 25 rows */
int i;
nIn = 46; assert( 46==sqlite3LogEst(25) );
/* The expression may actually be of the form (x, y) IN (SELECT...).
** In this case there is a separate term for each of (x) and (y).
** However, the nIn multiplier should only be applied once, not once
** for each such term. The following loop checks that pTerm is the
** first such term in use, and sets nIn back to 0 if it is not. */
for(i=0; i<pNew->nLTerm-1; i++){
if( pNew->aLTerm[i]->pExpr==pExpr ) nIn = 0;
}
}else if( ALWAYS(pExpr->x.pList && pExpr->x.pList->nExpr) ){
/* "x IN (value, value, ...)" */
nIn = sqlite3LogEst(pExpr->x.pList->nExpr);
assert( nIn>0 ); /* RHS always has 2 or more terms... The parser
** changes "x IN (?)" into "x=?". */
}
assert( nIn>0 ); /* RHS always has 2 or more terms... The parser
** changes "x IN (?)" into "x=?". */
}else if( eOp & (WO_EQ|WO_IS) ){
int iCol = pProbe->aiColumn[saved_nEq];
pNew->wsFlags |= WHERE_COLUMN_EQ;