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Overview
| Comment: | Avoid using left-most column STAT3 samples if the left-most column has an equality constrain and there are inequality constraints on the second column. |
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| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | trunk |
| Files: | files | file ages | folders |
| SHA1: |
31b4e63b3c30fcad22340d84d6076a30 |
| User & Date: | drh 2013-08-01 16:52:50 |
Context
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2013-08-01
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| 17:21 | An improved method for avoiding the use of the STAT3 samples to compute the estimated number of outputs when the left-most index is equality constrained. This check-in undoes the previous fix and applies a new one. (check-in: 127a5b77 user: drh tags: trunk) | |
| 16:52 | Avoid using left-most column STAT3 samples if the left-most column has an equality constrain and there are inequality constraints on the second column. (check-in: 31b4e63b user: drh tags: trunk) | |
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2013-07-31
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| 23:28 | Limit the number of memset() calls used when determining a temporary file name on Windows. Also, fix a harmless compiler warning. (check-in: 136fc293 user: mistachkin tags: trunk) | |
Changes
Changes to src/where.c.
4416 4417 4418 4419 4420 4421 4422 4423 4424 4425 4426 4427 4428 4429 4430 |
/* Adjust nOut and rRun for STAT3 range values */
WhereCost rDiv;
whereRangeScanEst(pParse, pProbe, pNew->u.btree.nEq,
pBtm, pTop, &rDiv);
pNew->nOut = saved_nOut>rDiv+10 ? saved_nOut - rDiv : 10;
}
#ifdef SQLITE_ENABLE_STAT3
if( pNew->u.btree.nEq==1 && pProbe->nSample
&& OptimizationEnabled(db, SQLITE_Stat3) ){
tRowcnt nOut = 0;
if( (pTerm->eOperator & (WO_EQ|WO_ISNULL))!=0 ){
testcase( pTerm->eOperator & WO_EQ );
testcase( pTerm->eOperator & WO_ISNULL );
rc = whereEqualScanEst(pParse, pProbe, pTerm->pExpr->pRight, &nOut);
}else if( (pTerm->eOperator & WO_IN)
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4416 4417 4418 4419 4420 4421 4422 4423 4424 4425 4426 4427 4428 4429 4430 |
/* Adjust nOut and rRun for STAT3 range values */
WhereCost rDiv;
whereRangeScanEst(pParse, pProbe, pNew->u.btree.nEq,
pBtm, pTop, &rDiv);
pNew->nOut = saved_nOut>rDiv+10 ? saved_nOut - rDiv : 10;
}
#ifdef SQLITE_ENABLE_STAT3
if( pNew->u.btree.nEq==1 && pProbe->nSample && saved_nEq==0
&& OptimizationEnabled(db, SQLITE_Stat3) ){
tRowcnt nOut = 0;
if( (pTerm->eOperator & (WO_EQ|WO_ISNULL))!=0 ){
testcase( pTerm->eOperator & WO_EQ );
testcase( pTerm->eOperator & WO_ISNULL );
rc = whereEqualScanEst(pParse, pProbe, pTerm->pExpr->pRight, &nOut);
}else if( (pTerm->eOperator & WO_IN)
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