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Add experimental "costmult" logic. Only enabled when compiled with

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-DSQLITE_ENABLE_COSTMULT.

FossilOrigin-Name: 729ece40885ed7f52c5981364833fc62281a388b
This commit is contained in:
drh
2014-07-23 23:57:42 +00:00
parent 11d451eb8a
commit dbd9486d5b
5 changed files with 35 additions and 13 deletions
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15
src/where.c
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@@ -4230,6 +4230,16 @@ static void whereLoopOutputAdjust(WhereClause *pWC, WhereLoop *pLoop){
}
}
/*
** Adjust the cost C by the costMult facter T. This only occurs if
** compiled with -DSQLITE_ENABLE_COSTMULT
*/
#ifdef SQLITE_ENABLE_COSTMULT
# define ApplyCostMultiplier(C,T) C += T
#else
# define ApplyCostMultiplier(C,T)
#endif
/*
** We have so far matched pBuilder->pNew->u.btree.nEq terms of the
** index pIndex. Try to match one more.
@@ -4457,6 +4467,7 @@ static int whereLoopAddBtreeIndex(
if( (pNew->wsFlags & (WHERE_IDX_ONLY|WHERE_IPK))==0 ){
pNew->rRun = sqlite3LogEstAdd(pNew->rRun, pNew->nOut + 16);
}
ApplyCostMultiplier(pNew->rRun, pProbe->pTable->costMult);
nOutUnadjusted = pNew->nOut;
pNew->rRun += nInMul + nIn;
@@ -4671,6 +4682,7 @@ static int whereLoopAddBtree(
** approximately 7*N*log2(N) where N is the number of rows in
** the table being indexed. */
pNew->rSetup = rLogSize + rSize + 28; assert( 28==sqlite3LogEst(7) );
ApplyCostMultiplier(pNew->rSetup, pTab->costMult);
/* TUNING: Each index lookup yields 20 rows in the table. This
** is more than the usual guess of 10 rows, since we have no way
** of knowning how selective the index will ultimately be. It would
@@ -4712,6 +4724,7 @@ static int whereLoopAddBtree(
pNew->iSortIdx = b ? iSortIdx : 0;
/* TUNING: Cost of full table scan is (N*3.0). */
pNew->rRun = rSize + 16;
ApplyCostMultiplier(pNew->rRun, pTab->costMult);
whereLoopOutputAdjust(pWC, pNew);
rc = whereLoopInsert(pBuilder, pNew);
pNew->nOut = rSize;
@@ -4747,7 +4760,7 @@ static int whereLoopAddBtree(
if( m!=0 ){
pNew->rRun = sqlite3LogEstAdd(pNew->rRun, rSize+16);
}
ApplyCostMultiplier(pNew->rRun, pTab->costMult);
whereLoopOutputAdjust(pWC, pNew);
rc = whereLoopInsert(pBuilder, pNew);
pNew->nOut = rSize;