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Improvements to likelihood processing so that commuting an unindexed term in

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the WHERE clause does not change the query plan.

FossilOrigin-Name: 6e6bded055cdbc902731687c86d92c39a3ba5904
This commit is contained in:
drh
2013-09-11 17:39:09 +00:00
parent 09328c00d6
commit 7d9e7d8287
4 changed files with 39 additions and 23 deletions
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26
src/where.c
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@@ -689,9 +689,7 @@ static int whereClauseInsert(WhereClause *pWC, Expr *p, u8 wtFlags){
pWC->nSlot = sqlite3DbMallocSize(db, pWC->a)/sizeof(pWC->a[0]);
}
pTerm = &pWC->a[idx = pWC->nTerm++];
if( wtFlags & TERM_VIRTUAL ){
pTerm->truthProb = 0;
}else if( ALWAYS(p) && ExprHasAnyProperty(p, EP_Hint) ){
if( p && ExprHasAnyProperty(p, EP_Hint) ){
pTerm->truthProb = whereCost(p->iTable) - 99;
}else{
pTerm->truthProb = -1;
@@ -4286,24 +4284,24 @@ whereLoopInsert_noop:
** reduces the number of output rows by sqrt(2).
*/
static void whereLoopOutputAdjust(WhereClause *pWC, WhereLoop *pLoop, int iCur){
WhereTerm *pTerm;
WhereTerm *pTerm, *pX;
Bitmask notAllowed = ~(pLoop->prereq|pLoop->maskSelf);
int x = 0;
int i;
int i, j;
if( !OptimizationEnabled(pWC->pWInfo->pParse->db, SQLITE_AdjustOutEst) ){
return;
}
for(i=pWC->nTerm, pTerm=pWC->a; i>0; i--, pTerm++){
if( (pTerm->wtFlags & TERM_VIRTUAL)!=0 ) continue;
if( (pTerm->wtFlags & TERM_VIRTUAL)!=0 ) break;
if( (pTerm->prereqAll & pLoop->maskSelf)==0 ) continue;
if( (pTerm->prereqAll & notAllowed)!=0 ) continue;
x += pTerm->truthProb;
for(j=pLoop->nLTerm-1; j>=0; j--){
pX = pLoop->aLTerm[j];
if( pX==pTerm ) break;
if( pX->iParent>=0 && (&pWC->a[pX->iParent])==pTerm ) break;
}
if( j<0 ) pLoop->nOut += pTerm->truthProb;
}
for(i=pLoop->nLTerm-1; i>=0; i--){
x -= pLoop->aLTerm[i]->truthProb;
}
if( x<0 ) pLoop->nOut += x;
}
/*
@@ -5426,9 +5424,7 @@ static int wherePathSolver(WhereInfo *pWInfo, WhereCost nRowEst){
}
}
if( jj>=nTo ){
if( nTo>=mxChoice
&& (rCost>mxCost || (rCost==mxCost && nOut>=mxOut))
){
if( nTo>=mxChoice && rCost>=mxCost ){
#ifdef WHERETRACE_ENABLED
if( sqlite3WhereTrace&0x4 ){
sqlite3DebugPrintf("Skip %s cost=%-3d,%3d order=%c\n",