diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/where.c | 149 |
1 files changed, 119 insertions, 30 deletions
diff --git a/src/where.c b/src/where.c index c1fc4301d..e6b3c3a53 100644 --- a/src/where.c +++ b/src/where.c @@ -4282,6 +4282,21 @@ static int indexMightHelpWithOrderBy( } /* +** Return a bitmask where 1s indicate that the corresponding column of +** the table is used by an index. Only the first 63 columns are considered. +*/ +static Bitmask columnsUsedByIndex(Index *pIdx){ + Bitmask m = 0; + int j; + for(j=pIdx->nColumn-1; j>=0; j--){ + int x = pIdx->aiColumn[j]; + if( x<BMS-1 ) m |= MASKBIT(x); + } + return m; +} + + +/* ** Add all WhereLoop objects a single table of the join were the table ** is idenfied by pBuilder->pNew->iTab. That table is guaranteed to be ** a b-tree table, not a virtual table. @@ -4388,14 +4403,7 @@ static int whereLoopAddBtree( rc = whereLoopInsert(pBuilder, pNew); if( rc ) break; }else{ - Bitmask m = pSrc->colUsed; - int j; - for(j=pProbe->nColumn-1; j>=0; j--){ - int x = pProbe->aiColumn[j]; - if( x<BMS-1 ){ - m &= ~MASKBIT(x); - } - } + Bitmask m = pSrc->colUsed & ~columnsUsedByIndex(pProbe); pNew->wsFlags = (m==0) ? (WHERE_IDX_ONLY|WHERE_INDEXED) : WHERE_INDEXED; /* Full scan via index */ @@ -5169,6 +5177,83 @@ static int wherePathSolver(WhereInfo *pWInfo, WhereCost nRowEst){ } /* +** Most queries use only a single table (they are not joins) and have +** simple == constraints against indexed fields. This routine attempts +** to plan those simple cases using much less ceremony than the +** general-purpose query planner, and thereby yield faster sqlite3_prepare() +** times for the common case. +** +** Return non-zero on success, if this query can be handled by this +** no-frills query planner. Return zero if this query needs the +** general-purpose query planner. +*/ +static int whereSimpleFastCase(WhereLoopBuilder *pBuilder){ + WhereInfo *pWInfo; + struct SrcList_item *pItem; + WhereClause *pWC; + WhereTerm *pTerm; + WhereLoop *pLoop; + int iCur; + int j; + int nOrderBy; + Table *pTab; + Index *pIdx; + + pWInfo = pBuilder->pWInfo; + assert( pWInfo->pTabList->nSrc>=1 ); + pItem = pWInfo->pTabList->a; + pTab = pItem->pTab; + if( IsVirtual(pTab) ) return 0; + if( pItem->zIndex ) return 0; + iCur = pItem->iCursor; + pWC = &pWInfo->sWC; + pLoop = pBuilder->pNew; + pWInfo->a[0].pWLoop = pLoop; + pLoop->wsFlags = 0; + pLoop->maskSelf = getMask(&pWInfo->sMaskSet, iCur); + pWInfo->a[0].iTabCur = iCur; +#ifdef SQLITE_DEBUG + pLoop->cId = '0'; +#endif + nOrderBy = pWInfo->pOrderBy ? pWInfo->pOrderBy->nExpr : 0; + pTerm = findTerm(pWC, iCur, -1, 1, WO_EQ, 0); + if( pTerm ){ + pLoop->wsFlags = WHERE_COLUMN_EQ|WHERE_IPK|WHERE_ONEROW; + pLoop->aLTerm[0] = pTerm; + pLoop->nLTerm = 1; + pLoop->u.btree.nEq = 1; + pLoop->rRun = (WhereCost)10; + pLoop->nOut = (WhereCost)1; + pWInfo->nRowOut = 1; + pWInfo->nOBSat = nOrderBy; + }else{ + for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){ + if( pIdx->onError==OE_None ) continue; + for(j=0; j<pIdx->nColumn; j++){ + pTerm = findTerm(pWC, iCur, pIdx->aiColumn[j], 1, WO_EQ, pIdx); + if( pTerm==0 ) break; + whereLoopResize(pWInfo->pParse->db, pLoop, j); + pLoop->aLTerm[j] = pTerm; + } + if( j!=pIdx->nColumn ) continue; + pLoop->wsFlags = WHERE_COLUMN_EQ|WHERE_ONEROW|WHERE_INDEXED; + if( (pItem->colUsed & ~columnsUsedByIndex(pIdx))==0 ){ + pLoop->wsFlags |= WHERE_IDX_ONLY; + } + pLoop->nLTerm = j; + pLoop->u.btree.nEq = j; + pLoop->u.btree.pIndex = pIdx; + pLoop->rRun = (WhereCost)15; + pLoop->nOut = (WhereCost)1; + pWInfo->nRowOut = 1; + pWInfo->nOBSat = nOrderBy; + break; + } + } + return pLoop->wsFlags!=0; +} + +/* ** Generate the beginning of the loop used for WHERE clause processing. ** The return value is a pointer to an opaque structure that contains ** information needed to terminate the loop. Later, the calling routine @@ -5307,7 +5392,7 @@ WhereInfo *sqlite3WhereBegin( */ db = pParse->db; nByteWInfo = ROUND8(sizeof(WhereInfo)+(nTabList-1)*sizeof(WhereLevel)); - pWInfo = sqlite3DbMallocZero(db, nByteWInfo); + pWInfo = sqlite3DbMallocZero(db, nByteWInfo + sizeof(WhereLoop)); if( db->mallocFailed ){ sqlite3DbFree(db, pWInfo); pWInfo = 0; @@ -5324,6 +5409,8 @@ WhereInfo *sqlite3WhereBegin( pMaskSet = &pWInfo->sMaskSet; sWLB.pWInfo = pWInfo; sWLB.pWC = &pWInfo->sWC; + sWLB.pNew = (WhereLoop*)&pWInfo->a[nTabList]; + whereLoopInit(sWLB.pNew); /* Disable the DISTINCT optimization if SQLITE_DistinctOpt is set via ** sqlite3_test_ctrl(SQLITE_TESTCTRL_OPTIMIZATIONS,...) */ @@ -5396,30 +5483,32 @@ WhereInfo *sqlite3WhereBegin( /* Construct the WhereLoop objects */ WHERETRACE(("*** Optimizer Start ***\n")); - /* TBD: if( nTablist==1 ) whereCommonCase(&sWLB); */ - rc = whereLoopAddAll(&sWLB); - if( rc ) goto whereBeginError; - - /* Display all of the WhereLoop objects if wheretrace is enabled */ + if( nTabList!=1 || whereSimpleFastCase(&sWLB)==0 ){ + rc = whereLoopAddAll(&sWLB); + if( rc ) goto whereBeginError; + + /* Display all of the WhereLoop objects if wheretrace is enabled */ #ifdef WHERETRACE_ENABLED - if( sqlite3WhereTrace ){ - WhereLoop *p; - int i = 0; - static char zLabel[] = "0123456789abcdefghijklmnopqrstuvwyxz" - "ABCDEFGHIJKLMNOPQRSTUVWYXZ"; - for(p=pWInfo->pLoops; p; p=p->pNextLoop){ - p->cId = zLabel[(i++)%sizeof(zLabel)]; - whereLoopPrint(p, pTabList); + if( sqlite3WhereTrace ){ + WhereLoop *p; + int i = 0; + static char zLabel[] = "0123456789abcdefghijklmnopqrstuvwyxz" + "ABCDEFGHIJKLMNOPQRSTUVWYXZ"; + for(p=pWInfo->pLoops; p; p=p->pNextLoop){ + p->cId = zLabel[(i++)%sizeof(zLabel)]; + whereLoopPrint(p, pTabList); + } } - } #endif - - wherePathSolver(pWInfo, -1); - if( db->mallocFailed ) goto whereBeginError; - if( pWInfo->pOrderBy ){ - wherePathSolver(pWInfo, pWInfo->nRowOut); - if( db->mallocFailed ) goto whereBeginError; - }else if( db->flags & SQLITE_ReverseOrder ){ + + wherePathSolver(pWInfo, -1); + if( db->mallocFailed ) goto whereBeginError; + if( pWInfo->pOrderBy ){ + wherePathSolver(pWInfo, pWInfo->nRowOut); + if( db->mallocFailed ) goto whereBeginError; + } + } + if( pWInfo->pOrderBy==0 && (db->flags & SQLITE_ReverseOrder)!=0 ){ pWInfo->revMask = (Bitmask)(-1); } if( pParse->nErr || db->mallocFailed ){ |