SQLite

Check-in [31b4e63b3c]
Login

Many hyperlinks are disabled.
Use anonymous login to enable hyperlinks.

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.
Downloads: Tarball | ZIP archive
Timelines: family | ancestors | descendants | both | trunk
Files: files | file ages | folders
SHA1: 31b4e63b3c30fcad22340d84d6076a306f26b49e
User & Date: drh 2013-08-01 16:52:50.320
Context
2013-08-01
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: 127a5b776d 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: 31b4e63b3c user: drh tags: trunk)
2013-07-31
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: 136fc2931b user: mistachkin tags: trunk)
Changes
Unified Diff Ignore Whitespace Patch
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)








|








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)
︙︙