SQLite

Check-in [127a5b776d]
Login

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

Overview
Comment: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.
Downloads: Tarball | ZIP archive
Timelines: family | ancestors | descendants | both | trunk
Files: files | file ages | folders
SHA1: 127a5b776d16e1e23c5b3d454f6aaea67f1ded3a
User & Date: drh 2013-08-01 17:21:26.855
References
2013-08-01
17:43
Add test case for the problem fixed by [127a5b776d]. (check-in: 65816718b5 user: dan tags: trunk)
Context
2013-08-01
17:43
Add test case for the problem fixed by [127a5b776d]. (check-in: 65816718b5 user: dan tags: trunk)
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)
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
4431
4432
4433

4434
4435
4436
4437
4438
4439
4440
4441

      /* 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)
             &&  !ExprHasProperty(pTerm->pExpr, EP_xIsSelect)  ){
        rc = whereInScanEst(pParse, pProbe, pTerm->pExpr->x.pList, &nOut);
      }

      if( rc==SQLITE_OK ) pNew->nOut = whereCost(nOut);
    }
#endif
    if( (pNew->wsFlags & (WHERE_IDX_ONLY|WHERE_IPK))==0 ){
      /* Each row involves a step of the index, then a binary search of
      ** the main table */
      pNew->rRun =  whereCostAdd(pNew->rRun, rLogSize>27 ? rLogSize-17 : 10);
    }








|










>
|








4416
4417
4418
4419
4420
4421
4422
4423
4424
4425
4426
4427
4428
4429
4430
4431
4432
4433
4434
4435
4436
4437
4438
4439
4440
4441
4442

      /* 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)
             &&  !ExprHasProperty(pTerm->pExpr, EP_xIsSelect)  ){
        rc = whereInScanEst(pParse, pProbe, pTerm->pExpr->x.pList, &nOut);
      }
      assert( nOut==0 || rc==SQLITE_OK );
      if( nOut ) pNew->nOut = whereCost(nOut);
    }
#endif
    if( (pNew->wsFlags & (WHERE_IDX_ONLY|WHERE_IPK))==0 ){
      /* Each row involves a step of the index, then a binary search of
      ** the main table */
      pNew->rRun =  whereCostAdd(pNew->rRun, rLogSize>27 ? rLogSize-17 : 10);
    }
︙︙