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Overview
Comment: | Add WHERETRACE debugging output to the whereLoopAdjustCost() routine. |
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Downloads: | Tarball | ZIP archive |
Timelines: | family | ancestors | descendants | both | trunk |
Files: | files | file ages | folders |
SHA1: |
ec1e942f08548695ff02645b3f3cd6bb |
User & Date: | drh 2014-10-21 16:01:40.774 |
Original Comment: | Improvements to the WHERETRACE debugging logic. |
Context
2014-10-21
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18:16 | Further tuning of the cost estimates for skip-scan loops, especially for cases when skip-scan loops are in competition with regular loops. (check-in: a27861c28c user: drh tags: trunk) | |
16:01 | Add WHERETRACE debugging output to the whereLoopAdjustCost() routine. (check-in: ec1e942f08 user: drh tags: trunk) | |
01:05 | If a skip-scan is a proper subset of some other scan, then adjust the cost of the skip-scan upward so that it is more costly than the other scan. Such a cost imbalance can arise under STAT4 because of difficulties in getting an accurate estimate for skip-scans. (check-in: f4b22a2620 user: drh tags: trunk) | |
Changes
Changes to src/where.c.
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3991 3992 3993 3994 3995 3996 3997 3998 3999 4000 4001 4002 4003 4004 4005 4006 4007 4008 4009 | if( (pTemplate->wsFlags & WHERE_INDEXED)==0 ) return; for(; p; p=p->pNextLoop){ if( p->iTab!=pTemplate->iTab ) continue; if( (p->wsFlags & WHERE_INDEXED)==0 ) continue; if( whereLoopCheaperProperSubset(p, pTemplate) ){ /* Adjust pTemplate cost downward so that it is cheaper than its ** subset p */ pTemplate->rRun = p->rRun; pTemplate->nOut = p->nOut - 1; }else if( whereLoopCheaperProperSubset(pTemplate, p) ){ /* Adjust pTemplate cost upward so that it is costlier than p since ** pTemplate is a proper subset of p */ pTemplate->rRun = p->rRun; pTemplate->nOut = p->nOut + 1; } } } /* | > > > > | 3991 3992 3993 3994 3995 3996 3997 3998 3999 4000 4001 4002 4003 4004 4005 4006 4007 4008 4009 4010 4011 4012 4013 | if( (pTemplate->wsFlags & WHERE_INDEXED)==0 ) return; for(; p; p=p->pNextLoop){ if( p->iTab!=pTemplate->iTab ) continue; if( (p->wsFlags & WHERE_INDEXED)==0 ) continue; if( whereLoopCheaperProperSubset(p, pTemplate) ){ /* Adjust pTemplate cost downward so that it is cheaper than its ** subset p */ WHERETRACE(0x80,("subset cost adjustment %d,%d to %d,%d\n", pTemplate->rRun, pTemplate->nOut, p->rRun, p->nOut-1)); pTemplate->rRun = p->rRun; pTemplate->nOut = p->nOut - 1; }else if( whereLoopCheaperProperSubset(pTemplate, p) ){ /* Adjust pTemplate cost upward so that it is costlier than p since ** pTemplate is a proper subset of p */ WHERETRACE(0x80,("subset cost adjustment %d,%d to %d,%d\n", pTemplate->rRun, pTemplate->nOut, p->rRun, p->nOut+1)); pTemplate->rRun = p->rRun; pTemplate->nOut = p->nOut + 1; } } } /* |
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5747 5748 5749 5750 5751 5752 5753 | } } } } } #ifdef WHERETRACE_ENABLED /* >=2 */ | | | 5751 5752 5753 5754 5755 5756 5757 5758 5759 5760 5761 5762 5763 5764 5765 | } } } } } #ifdef WHERETRACE_ENABLED /* >=2 */ if( sqlite3WhereTrace & 0x02 ){ sqlite3DebugPrintf("---- after round %d ----\n", iLoop); for(ii=0, pTo=aTo; ii<nTo; ii++, pTo++){ sqlite3DebugPrintf(" %s cost=%-3d nrow=%-3d order=%c", wherePathName(pTo, iLoop+1, 0), pTo->rCost, pTo->nRow, pTo->isOrdered>=0 ? (pTo->isOrdered+'0') : '?'); if( pTo->isOrdered>0 ){ sqlite3DebugPrintf(" rev=0x%llx\n", pTo->revLoop); |
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