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Modify internal function whereLoopAdjustCost() so that it does not prefer a skip-scan over a regular index scan even if the regular scan uses a subset of the WHERE terms used by the skip-scan.

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FossilOrigin-Name: 88a5758dcce891eb7be15432ebdc9f80071d413b
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dan
2014-04-28 09:35:31 +00:00
parent 440e6ff3b0
commit e3bfbb7284
3 changed files with 9 additions and 7 deletions
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2
src/where.c
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@@ -3779,9 +3779,11 @@ static int whereLoopCheaperProperSubset(
*/
static void whereLoopAdjustCost(const WhereLoop *p, WhereLoop *pTemplate){
if( (pTemplate->wsFlags & WHERE_INDEXED)==0 ) return;
if( (pTemplate->wsFlags & WHERE_SKIPSCAN)!=0 ) return;
for(; p; p=p->pNextLoop){
if( p->iTab!=pTemplate->iTab ) continue;
if( (p->wsFlags & WHERE_INDEXED)==0 ) continue;
if( (p->wsFlags & WHERE_SKIPSCAN)!=0 ) continue;
if( whereLoopCheaperProperSubset(p, pTemplate) ){
/* Adjust pTemplate cost downward so that it is cheaper than its
** subset p */