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Try to factor constant subcomponents of the WHERE clause out of the loop.

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FossilOrigin-Name: 9d05777fe24e1a5ce71762de38db840931ef0bc8
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drh
2014-01-02 21:05:10 +00:00
parent 762c1c4071
commit 759e858811
3 changed files with 13 additions and 10 deletions
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9
src/where.c
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@@ -5430,9 +5430,12 @@ WhereInfo *sqlite3WhereBegin(
/* 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 || sqlite3ExprIsConstantNotJoin(pWhere)) ){
sqlite3ExprIfFalse(pParse, pWhere, pWInfo->iBreak, SQLITE_JUMPIFNULL);
pWhere = 0;
for(ii=0; ii<sWLB.pWC->nTerm; ii++){
if( nTabList==0 || sqlite3ExprIsConstantNotJoin(sWLB.pWC->a[ii].pExpr) ){
sqlite3ExprIfFalse(pParse, sWLB.pWC->a[ii].pExpr, pWInfo->iBreak,
SQLITE_JUMPIFNULL);
sWLB.pWC->a[ii].wtFlags |= TERM_CODED;
}
}
/* Special case: No FROM clause