diff options
Diffstat (limited to 'src/where.c')
| -rw-r--r-- | src/where.c | 1186 |
1 files changed, 783 insertions, 403 deletions
diff --git a/src/where.c b/src/where.c index fd5831872..183a8cb66 100644 --- a/src/where.c +++ b/src/where.c @@ -222,10 +222,11 @@ static int whereClauseInsert(WhereClause *pWC, Expr *p, u8 wtFlags){ sqlite3DbFree(db, pOld); } pWC->nSlot = sqlite3DbMallocSize(db, pWC->a)/sizeof(pWC->a[0]); + memset(&pWC->a[pWC->nTerm], 0, sizeof(pWC->a[0])*(pWC->nSlot-pWC->nTerm)); } pTerm = &pWC->a[idx = pWC->nTerm++]; if( p && ExprHasProperty(p, EP_Unlikely) ){ - pTerm->truthProb = sqlite3LogEst(p->iTable) - 99; + pTerm->truthProb = sqlite3LogEst(p->iTable) - 270; }else{ pTerm->truthProb = 1; } @@ -365,11 +366,6 @@ static int allowedOp(int op){ } /* -** Swap two objects of type TYPE. -*/ -#define SWAP(TYPE,A,B) {TYPE t=A; A=B; B=t;} - -/* ** Commute a comparison operator. Expressions of the form "X op Y" ** are converted into "Y op X". ** @@ -544,7 +540,7 @@ static WhereTerm *whereScanInit( if( pIdx && iColumn>=0 ){ pScan->idxaff = pIdx->pTable->aCol[iColumn].affinity; for(j=0; pIdx->aiColumn[j]!=iColumn; j++){ - if( NEVER(j>=pIdx->nKeyCol) ) return 0; + if( NEVER(j>pIdx->nColumn) ) return 0; } pScan->zCollName = pIdx->azColl[j]; }else{ @@ -701,7 +697,7 @@ static int isLikeOrGlob( ** value of the variable means there is no need to invoke the LIKE ** function, then no OP_Variable will be added to the program. ** This causes problems for the sqlite3_bind_parameter_name() - ** API. To workaround them, add a dummy OP_Variable here. + ** API. To work around them, add a dummy OP_Variable here. */ int r1 = sqlite3GetTempReg(pParse); sqlite3ExprCodeTarget(pParse, pRight, r1); @@ -761,6 +757,15 @@ static void transferJoinMarkings(Expr *pDerived, Expr *pBase){ } } +/* +** Mark term iChild as being a child of term iParent +*/ +static void markTermAsChild(WhereClause *pWC, int iChild, int iParent){ + pWC->a[iChild].iParent = iParent; + pWC->a[iChild].truthProb = pWC->a[iParent].truthProb; + pWC->a[iParent].nChild++; +} + #if !defined(SQLITE_OMIT_OR_OPTIMIZATION) && !defined(SQLITE_OMIT_SUBQUERY) /* ** Analyze a term that consists of two or more OR-connected @@ -821,7 +826,7 @@ static void transferJoinMarkings(Expr *pDerived, Expr *pBase){ ** appropriate for indexing exist. ** ** All examples A through E above satisfy case 2. But if a term -** also statisfies case 1 (such as B) we know that the optimizer will +** also satisfies case 1 (such as B) we know that the optimizer will ** always prefer case 1, so in that case we pretend that case 2 is not ** satisfied. ** @@ -979,7 +984,7 @@ static void exprAnalyzeOrTerm( } if( (chngToIN & getMask(&pWInfo->sMaskSet, pOrTerm->leftCursor))==0 ){ /* This term must be of the form t1.a==t2.b where t2 is in the - ** chngToIN set but t1 is not. This term will be either preceeded + ** chngToIN set but t1 is not. This term will be either preceded ** or follwed by an inverted copy (t2.b==t1.a). Skip this term ** and use its inversion. */ testcase( pOrTerm->wtFlags & TERM_COPIED ); @@ -1058,8 +1063,7 @@ static void exprAnalyzeOrTerm( testcase( idxNew==0 ); exprAnalyze(pSrc, pWC, idxNew); pTerm = &pWC->a[idxTerm]; - pWC->a[idxNew].iParent = idxTerm; - pTerm->nChild = 1; + markTermAsChild(pWC, idxNew, idxTerm); }else{ sqlite3ExprListDelete(db, pList); } @@ -1161,9 +1165,8 @@ static void exprAnalyze( idxNew = whereClauseInsert(pWC, pDup, TERM_VIRTUAL|TERM_DYNAMIC); if( idxNew==0 ) return; pNew = &pWC->a[idxNew]; - pNew->iParent = idxTerm; + markTermAsChild(pWC, idxNew, idxTerm); pTerm = &pWC->a[idxTerm]; - pTerm->nChild = 1; pTerm->wtFlags |= TERM_COPIED; if( pExpr->op==TK_EQ && !ExprHasProperty(pExpr, EP_FromJoin) @@ -1220,9 +1223,8 @@ static void exprAnalyze( testcase( idxNew==0 ); exprAnalyze(pSrc, pWC, idxNew); pTerm = &pWC->a[idxTerm]; - pWC->a[idxNew].iParent = idxTerm; + markTermAsChild(pWC, idxNew, idxTerm); } - pTerm->nChild = 2; } #endif /* SQLITE_OMIT_BETWEEN_OPTIMIZATION */ @@ -1297,9 +1299,8 @@ static void exprAnalyze( exprAnalyze(pSrc, pWC, idxNew2); pTerm = &pWC->a[idxTerm]; if( isComplete ){ - pWC->a[idxNew1].iParent = idxTerm; - pWC->a[idxNew2].iParent = idxTerm; - pTerm->nChild = 2; + markTermAsChild(pWC, idxNew1, idxTerm); + markTermAsChild(pWC, idxNew2, idxTerm); } } #endif /* SQLITE_OMIT_LIKE_OPTIMIZATION */ @@ -1332,9 +1333,8 @@ static void exprAnalyze( pNewTerm->leftCursor = pLeft->iTable; pNewTerm->u.leftColumn = pLeft->iColumn; pNewTerm->eOperator = WO_MATCH; - pNewTerm->iParent = idxTerm; + markTermAsChild(pWC, idxNew, idxTerm); pTerm = &pWC->a[idxTerm]; - pTerm->nChild = 1; pTerm->wtFlags |= TERM_COPIED; pNewTerm->prereqAll = pTerm->prereqAll; } @@ -1355,7 +1355,7 @@ static void exprAnalyze( if( pExpr->op==TK_NOTNULL && pExpr->pLeft->op==TK_COLUMN && pExpr->pLeft->iColumn>=0 - && OptimizationEnabled(db, SQLITE_Stat3) + && OptimizationEnabled(db, SQLITE_Stat34) ){ Expr *pNewExpr; Expr *pLeft = pExpr->pLeft; @@ -1374,9 +1374,8 @@ static void exprAnalyze( pNewTerm->leftCursor = pLeft->iTable; pNewTerm->u.leftColumn = pLeft->iColumn; pNewTerm->eOperator = WO_GT; - pNewTerm->iParent = idxTerm; + markTermAsChild(pWC, idxNew, idxTerm); pTerm = &pWC->a[idxTerm]; - pTerm->nChild = 1; pTerm->wtFlags |= TERM_COPIED; pNewTerm->prereqAll = pTerm->prereqAll; } @@ -1390,7 +1389,7 @@ static void exprAnalyze( } /* -** This function searches pList for a entry that matches the iCol-th column +** This function searches pList for an entry that matches the iCol-th column ** of index pIdx. ** ** If such an expression is found, its index in pList->a[] is returned. If @@ -1470,7 +1469,7 @@ static int isDistinctRedundant( ** contain a "col=X" term are subject to a NOT NULL constraint. */ for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){ - if( pIdx->onError==OE_None ) continue; + if( !IsUniqueIndex(pIdx) ) continue; for(i=0; i<pIdx->nKeyCol; i++){ i16 iCol = pIdx->aiColumn[i]; if( 0==findTerm(pWC, iBase, iCol, ~(Bitmask)0, WO_EQ, pIdx) ){ @@ -1596,6 +1595,8 @@ static void constructAutomaticIndex( Bitmask idxCols; /* Bitmap of columns used for indexing */ Bitmask extraCols; /* Bitmap of additional columns */ u8 sentWarning = 0; /* True if a warnning has been issued */ + Expr *pPartial = 0; /* Partial Index Expression */ + int iContinue = 0; /* Jump here to skip excluded rows */ /* Generate code to skip over the creation and initialization of the ** transient index on 2nd and subsequent iterations of the loop. */ @@ -1611,6 +1612,12 @@ static void constructAutomaticIndex( pLoop = pLevel->pWLoop; idxCols = 0; for(pTerm=pWC->a; pTerm<pWCEnd; pTerm++){ + if( pLoop->prereq==0 + && (pTerm->wtFlags & TERM_VIRTUAL)==0 + && sqlite3ExprIsTableConstant(pTerm->pExpr, pSrc->iCursor) ){ + pPartial = sqlite3ExprAnd(pParse->db, pPartial, + sqlite3ExprDup(pParse->db, pTerm->pExpr, 0)); + } if( termCanDriveIndex(pTerm, pSrc, notReady) ){ int iCol = pTerm->u.leftColumn; Bitmask cMask = iCol>=BMS ? MASKBIT(BMS-1) : MASKBIT(iCol); @@ -1623,7 +1630,9 @@ static void constructAutomaticIndex( sentWarning = 1; } if( (idxCols & cMask)==0 ){ - if( whereLoopResize(pParse->db, pLoop, nKeyCol+1) ) return; + if( whereLoopResize(pParse->db, pLoop, nKeyCol+1) ){ + goto end_auto_index_create; + } pLoop->aLTerm[nKeyCol++] = pTerm; idxCols |= cMask; } @@ -1643,7 +1652,7 @@ static void constructAutomaticIndex( ** if they go out of sync. */ extraCols = pSrc->colUsed & (~idxCols | MASKBIT(BMS-1)); - mxBitCol = (pTable->nCol >= BMS-1) ? BMS-1 : pTable->nCol; + mxBitCol = MIN(BMS-1,pTable->nCol); testcase( pTable->nCol==BMS-1 ); testcase( pTable->nCol==BMS-2 ); for(i=0; i<mxBitCol; i++){ @@ -1652,11 +1661,10 @@ static void constructAutomaticIndex( if( pSrc->colUsed & MASKBIT(BMS-1) ){ nKeyCol += pTable->nCol - BMS + 1; } - pLoop->wsFlags |= WHERE_COLUMN_EQ | WHERE_IDX_ONLY; /* Construct the Index object to describe this index */ pIdx = sqlite3AllocateIndexObject(pParse->db, nKeyCol+1, 0, &zNotUsed); - if( pIdx==0 ) return; + if( pIdx==0 ) goto end_auto_index_create; pLoop->u.btree.pIndex = pIdx; pIdx->zName = "auto-index"; pIdx->pTable = pTable; @@ -1708,18 +1716,29 @@ static void constructAutomaticIndex( VdbeComment((v, "for %s", pTable->zName)); /* Fill the automatic index with content */ + sqlite3ExprCachePush(pParse); addrTop = sqlite3VdbeAddOp1(v, OP_Rewind, pLevel->iTabCur); VdbeCoverage(v); + if( pPartial ){ + iContinue = sqlite3VdbeMakeLabel(v); + sqlite3ExprIfFalse(pParse, pPartial, iContinue, SQLITE_JUMPIFNULL); + pLoop->wsFlags |= WHERE_PARTIALIDX; + } regRecord = sqlite3GetTempReg(pParse); sqlite3GenerateIndexKey(pParse, pIdx, pLevel->iTabCur, regRecord, 0, 0, 0, 0); sqlite3VdbeAddOp2(v, OP_IdxInsert, pLevel->iIdxCur, regRecord); sqlite3VdbeChangeP5(v, OPFLAG_USESEEKRESULT); + if( pPartial ) sqlite3VdbeResolveLabel(v, iContinue); sqlite3VdbeAddOp2(v, OP_Next, pLevel->iTabCur, addrTop+1); VdbeCoverage(v); sqlite3VdbeChangeP5(v, SQLITE_STMTSTATUS_AUTOINDEX); sqlite3VdbeJumpHere(v, addrTop); sqlite3ReleaseTempReg(pParse, regRecord); + sqlite3ExprCachePop(pParse); /* Jump here when skipping the initialization */ sqlite3VdbeJumpHere(v, addrInit); + +end_auto_index_create: + sqlite3ExprDelete(pParse->db, pPartial); } #endif /* SQLITE_OMIT_AUTOMATIC_INDEX */ @@ -1879,7 +1898,6 @@ static int vtabBestIndex(Parse *pParse, Table *pTab, sqlite3_index_info *p){ } #endif /* !defined(SQLITE_OMIT_VIRTUALTABLE) */ - #ifdef SQLITE_ENABLE_STAT3_OR_STAT4 /* ** Estimate the location of a particular key among all keys in an @@ -1888,9 +1906,10 @@ static int vtabBestIndex(Parse *pParse, Table *pTab, sqlite3_index_info *p){ ** aStat[0] Est. number of rows less than pVal ** aStat[1] Est. number of rows equal to pVal ** -** Return SQLITE_OK on success. +** Return the index of the sample that is the smallest sample that +** is greater than or equal to pRec. */ -static void whereKeyStats( +static int whereKeyStats( Parse *pParse, /* Database connection */ Index *pIdx, /* Index to consider domain of */ UnpackedRecord *pRec, /* Vector of values to consider */ @@ -1913,7 +1932,7 @@ static void whereKeyStats( assert( pRec->nField>0 && iCol<pIdx->nSampleCol ); do{ iTest = (iMin+i)/2; - res = sqlite3VdbeRecordCompare(aSample[iTest].n, aSample[iTest].p, pRec, 0); + res = sqlite3VdbeRecordCompare(aSample[iTest].n, aSample[iTest].p, pRec); if( res<0 ){ iMin = iTest+1; }else{ @@ -1928,16 +1947,16 @@ static void whereKeyStats( if( res==0 ){ /* If (res==0) is true, then sample $i must be equal to pRec */ assert( i<pIdx->nSample ); - assert( 0==sqlite3VdbeRecordCompare(aSample[i].n, aSample[i].p, pRec, 0) + assert( 0==sqlite3VdbeRecordCompare(aSample[i].n, aSample[i].p, pRec) || pParse->db->mallocFailed ); }else{ /* Otherwise, pRec must be smaller than sample $i and larger than ** sample ($i-1). */ assert( i==pIdx->nSample - || sqlite3VdbeRecordCompare(aSample[i].n, aSample[i].p, pRec, 0)>0 + || sqlite3VdbeRecordCompare(aSample[i].n, aSample[i].p, pRec)>0 || pParse->db->mallocFailed ); assert( i==0 - || sqlite3VdbeRecordCompare(aSample[i-1].n, aSample[i-1].p, pRec, 0)<0 + || sqlite3VdbeRecordCompare(aSample[i-1].n, aSample[i-1].p, pRec)<0 || pParse->db->mallocFailed ); } #endif /* ifdef SQLITE_DEBUG */ @@ -1959,7 +1978,7 @@ static void whereKeyStats( iUpper = i>=pIdx->nSample ? nRow0 : aSample[i].anLt[iCol]; iLower = aSample[i-1].anEq[iCol] + aSample[i-1].anLt[iCol]; } - aStat[1] = (pIdx->nKeyCol>iCol ? pIdx->aAvgEq[iCol] : 1); + aStat[1] = pIdx->aAvgEq[iCol]; if( iLower>=iUpper ){ iGap = 0; }else{ @@ -1972,6 +1991,7 @@ static void whereKeyStats( } aStat[0] = iLower + iGap; } + return i; } #endif /* SQLITE_ENABLE_STAT3_OR_STAT4 */ @@ -1998,6 +2018,115 @@ static LogEst whereRangeAdjust(WhereTerm *pTerm, LogEst nNew){ return nRet; } +#ifdef SQLITE_ENABLE_STAT3_OR_STAT4 +/* +** This function is called to estimate the number of rows visited by a +** range-scan on a skip-scan index. For example: +** +** CREATE INDEX i1 ON t1(a, b, c); +** SELECT * FROM t1 WHERE a=? AND c BETWEEN ? AND ?; +** +** Value pLoop->nOut is currently set to the estimated number of rows +** visited for scanning (a=? AND b=?). This function reduces that estimate +** by some factor to account for the (c BETWEEN ? AND ?) expression based +** on the stat4 data for the index. this scan will be peformed multiple +** times (once for each (a,b) combination that matches a=?) is dealt with +** by the caller. +** +** It does this by scanning through all stat4 samples, comparing values +** extracted from pLower and pUpper with the corresponding column in each +** sample. If L and U are the number of samples found to be less than or +** equal to the values extracted from pLower and pUpper respectively, and +** N is the total number of samples, the pLoop->nOut value is adjusted +** as follows: +** +** nOut = nOut * ( min(U - L, 1) / N ) +** +** If pLower is NULL, or a value cannot be extracted from the term, L is +** set to zero. If pUpper is NULL, or a value cannot be extracted from it, +** U is set to N. +** +** Normally, this function sets *pbDone to 1 before returning. However, +** if no value can be extracted from either pLower or pUpper (and so the +** estimate of the number of rows delivered remains unchanged), *pbDone +** is left as is. +** +** If an error occurs, an SQLite error code is returned. Otherwise, +** SQLITE_OK. +*/ +static int whereRangeSkipScanEst( + Parse *pParse, /* Parsing & code generating context */ + WhereTerm *pLower, /* Lower bound on the range. ex: "x>123" Might be NULL */ + WhereTerm *pUpper, /* Upper bound on the range. ex: "x<455" Might be NULL */ + WhereLoop *pLoop, /* Update the .nOut value of this loop */ + int *pbDone /* Set to true if at least one expr. value extracted */ +){ + Index *p = pLoop->u.btree.pIndex; + int nEq = pLoop->u.btree.nEq; + sqlite3 *db = pParse->db; + int nLower = -1; + int nUpper = p->nSample+1; + int rc = SQLITE_OK; + int iCol = p->aiColumn[nEq]; + u8 aff = iCol>=0 ? p->pTable->aCol[iCol].affinity : SQLITE_AFF_INTEGER; + CollSeq *pColl; + + sqlite3_value *p1 = 0; /* Value extracted from pLower */ + sqlite3_value *p2 = 0; /* Value extracted from pUpper */ + sqlite3_value *pVal = 0; /* Value extracted from record */ + + pColl = sqlite3LocateCollSeq(pParse, p->azColl[nEq]); + if( pLower ){ + rc = sqlite3Stat4ValueFromExpr(pParse, pLower->pExpr->pRight, aff, &p1); + nLower = 0; + } + if( pUpper && rc==SQLITE_OK ){ + rc = sqlite3Stat4ValueFromExpr(pParse, pUpper->pExpr->pRight, aff, &p2); + nUpper = p2 ? 0 : p->nSample; + } + + if( p1 || p2 ){ + int i; + int nDiff; + for(i=0; rc==SQLITE_OK && i<p->nSample; i++){ + rc = sqlite3Stat4Column(db, p->aSample[i].p, p->aSample[i].n, nEq, &pVal); + if( rc==SQLITE_OK && p1 ){ + int res = sqlite3MemCompare(p1, pVal, pColl); + if( res>=0 ) nLower++; + } + if( rc==SQLITE_OK && p2 ){ + int res = sqlite3MemCompare(p2, pVal, pColl); + if( res>=0 ) nUpper++; + } + } + nDiff = (nUpper - nLower); + if( nDiff<=0 ) nDiff = 1; + + /* If there is both an upper and lower bound specified, and the + ** comparisons indicate that they are close together, use the fallback + ** method (assume that the scan visits 1/64 of the rows) for estimating + ** the number of rows visited. Otherwise, estimate the number of rows + ** using the method described in the header comment for this function. */ + if( nDiff!=1 || pUpper==0 || pLower==0 ){ + int nAdjust = (sqlite3LogEst(p->nSample) - sqlite3LogEst(nDiff)); + pLoop->nOut -= nAdjust; + *pbDone = 1; + WHERETRACE(0x10, ("range skip-scan regions: %u..%u adjust=%d est=%d\n", + nLower, nUpper, nAdjust*-1, pLoop->nOut)); + } + + }else{ + assert( *pbDone==0 ); + } + + sqlite3ValueFree(p1); + sqlite3ValueFree(p2); + sqlite3ValueFree(pVal); + + return rc; +} +#endif /* SQLITE_ENABLE_STAT3_OR_STAT4 */ + /* ** This function is used to estimate the number of rows that will be visited ** by scanning an index for a range of values. The range may have an upper @@ -2013,7 +2142,7 @@ static LogEst whereRangeAdjust(WhereTerm *pTerm, LogEst nNew){ ** If either of the upper or lower bound is not present, then NULL is passed in ** place of the corresponding WhereTerm. ** -** The value in (pBuilder->pNew->u.btree.nEq) is the index of the index +** The value in (pBuilder->pNew->u.btree.nEq) is the number of the index ** column subject to the range constraint. Or, equivalently, the number of ** equality constraints optimized by the proposed index scan. For example, ** assuming index p is on t1(a, b), and the SQL query is: @@ -2029,9 +2158,9 @@ static LogEst whereRangeAdjust(WhereTerm *pTerm, LogEst nNew){ ** ** When this function is called, *pnOut is set to the sqlite3LogEst() of the ** number of rows that the index scan is expected to visit without -** considering the range constraints. If nEq is 0, this is the number of +** considering the range constraints. If nEq is 0, then *pnOut is the number of ** rows in the index. Assuming no error occurs, *pnOut is adjusted (reduced) -** to account for the range contraints pLower and pUpper. +** to account for the range constraints pLower and pUpper. ** ** In the absence of sqlite_stat4 ANALYZE data, or if such data cannot be ** used, a single range inequality reduces the search space by a factor of 4. @@ -2053,117 +2182,147 @@ static int whereRangeScanEst( Index *p = pLoop->u.btree.pIndex; int nEq = pLoop->u.btree.nEq; - if( p->nSample>0 - && nEq==pBuilder->nRecValid - && nEq<p->nSampleCol - && OptimizationEnabled(pParse->db, SQLITE_Stat3) - ){ - UnpackedRecord *pRec = pBuilder->pRec; - tRowcnt a[2]; - u8 aff; - - /* Variable iLower will be set to the estimate of the number of rows in - ** the index that are less than the lower bound of the range query. The - ** lower bound being the concatenation of $P and $L, where $P is the - ** key-prefix formed by the nEq values matched against the nEq left-most - ** columns of the index, and $L is the value in pLower. - ** - ** Or, if pLower is NULL or $L cannot be extracted from it (because it - ** is not a simple variable or literal value), the lower bound of the - ** range is $P. Due to a quirk in the way whereKeyStats() works, even - ** if $L is available, whereKeyStats() is called for both ($P) and - ** ($P:$L) and the larger of the two returned values used. - ** - ** Similarly, iUpper is to be set to the estimate of the number of rows - ** less than the upper bound of the range query. Where the upper bound - ** is either ($P) or ($P:$U). Again, even if $U is available, both values - ** of iUpper are requested of whereKeyStats() and the smaller used. - */ - tRowcnt iLower; - tRowcnt iUpper; - - if( nEq==p->nKeyCol ){ - aff = SQLITE_AFF_INTEGER; - }else{ - aff = p->pTable->aCol[p->aiColumn[nEq]].affinity; - } - /* Determine iLower and iUpper using ($P) only. */ - if( nEq==0 ){ - iLower = 0; - iUpper = sqlite3LogEstToInt(p->aiRowLogEst[0]); - }else{ - /* Note: this call could be optimized away - since the same values must - ** have been requested when testing key $P in whereEqualScanEst(). */ - whereKeyStats(pParse, p, pRec, 0, a); - iLower = a[0]; - iUpper = a[0] + a[1]; - } - - /* If possible, improve on the iLower estimate using ($P:$L). */ - if( pLower ){ - int bOk; /* True if value is extracted from pExpr */ - Expr *pExpr = pLower->pExpr->pRight; - assert( (pLower->eOperator & (WO_GT|WO_GE))!=0 ); - rc = sqlite3Stat4ProbeSetValue(pParse, p, &pRec, pExpr, aff, nEq, &bOk); - if( rc==SQLITE_OK && bOk ){ - tRowcnt iNew; + if( p->nSample>0 && nEq<p->nSampleCol ){ + if( nEq==pBuilder->nRecValid ){ + UnpackedRecord *pRec = pBuilder->pRec; + tRowcnt a[2]; + u8 aff; + + /* Variable iLower will be set to the estimate of the number of rows in + ** the index that are less than the lower bound of the range query. The + ** lower bound being the concatenation of $P and $L, where $P is the + ** key-prefix formed by the nEq values matched against the nEq left-most + ** columns of the index, and $L is the value in pLower. + ** + ** Or, if pLower is NULL or $L cannot be extracted from it (because it + ** is not a simple variable or literal value), the lower bound of the + ** range is $P. Due to a quirk in the way whereKeyStats() works, even + ** if $L is available, whereKeyStats() is called for both ($P) and + ** ($P:$L) and the larger of the two returned values is used. + ** + ** Similarly, iUpper is to be set to the estimate of the number of rows + ** less than the upper bound of the range query. Where the upper bound + ** is either ($P) or ($P:$U). Again, even if $U is available, both values + ** of iUpper are requested of whereKeyStats() and the smaller used. + ** + ** The number of rows between the two bounds is then just iUpper-iLower. + */ + tRowcnt iLower; /* Rows less than the lower bound */ + tRowcnt iUpper; /* Rows less than the upper bound */ + int iLwrIdx = -2; /* aSample[] for the lower bound */ + int iUprIdx = -1; /* aSample[] for the upper bound */ + + if( pRec ){ + testcase( pRec->nField!=pBuilder->nRecValid ); + pRec->nField = pBuilder->nRecValid; + } + if( nEq==p->nKeyCol ){ + aff = SQLITE_AFF_INTEGER; + }else{ + aff = p->pTable->aCol[p->aiColumn[nEq]].affinity; + } + /* Determine iLower and iUpper using ($P) only. */ + if( nEq==0 ){ + iLower = 0; + iUpper = p->nRowEst0; + }else{ + /* Note: this call could be optimized away - since the same values must + ** have been requested when testing key $P in whereEqualScanEst(). */ whereKeyStats(pParse, p, pRec, 0, a); - iNew = a[0] + ((pLower->eOperator & WO_GT) ? a[1] : 0); - if( iNew>iLower ) iLower = iNew; - nOut--; + iLower = a[0]; + iUpper = a[0] + a[1]; } - } - /* If possible, improve on the iUpper estimate using ($P:$U). */ - if( pUpper ){ - int bOk; /* True if value is extracted from pExpr */ - Expr *pExpr = pUpper->pExpr->pRight; - assert( (pUpper->eOperator & (WO_LT|WO_LE))!=0 ); - rc = sqlite3Stat4ProbeSetValue(pParse, p, &pRec, pExpr, aff, nEq, &bOk); - if( rc==SQLITE_OK && bOk ){ - tRowcnt iNew; - whereKeyStats(pParse, p, pRec, 1, a); - iNew = a[0] + ((pUpper->eOperator & WO_LE) ? a[1] : 0); - if( iNew<iUpper ) iUpper = iNew; - nOut--; + assert( pLower==0 || (pLower->eOperator & (WO_GT|WO_GE))!=0 ); + assert( pUpper==0 || (pUpper->eOperator & (WO_LT|WO_LE))!=0 ); + assert( p->aSortOrder!=0 ); + if( p->aSortOrder[nEq] ){ + /* The roles of pLower and pUpper are swapped for a DESC index */ + SWAP(WhereTerm*, pLower, pUpper); } - } - pBuilder->pRec = pRec; - if( rc==SQLITE_OK ){ - if( iUpper>iLower ){ - nNew = sqlite3LogEst(iUpper - iLower); - }else{ - nNew = 10; assert( 10==sqlite3LogEst(2) ); + /* If possible, improve on the iLower estimate using ($P:$L). */ + if( pLower ){ + int bOk; /* True if value is extracted from pExpr */ + Expr *pExpr = pLower->pExpr->pRight; + rc = sqlite3Stat4ProbeSetValue(pParse, p, &pRec, pExpr, aff, nEq, &bOk); + if( rc==SQLITE_OK && bOk ){ + tRowcnt iNew; + iLwrIdx = whereKeyStats(pParse, p, pRec, 0, a); + iNew = a[0] + ((pLower->eOperator & (WO_GT|WO_LE)) ? a[1] : 0); + if( iNew>iLower ) iLower = iNew; + nOut--; + pLower = 0; + } } - if( nNew<nOut ){ - nOut = nNew; + + /* If possible, improve on the iUpper estimate using ($P:$U). */ + if( pUpper ){ + int bOk; /* True if value is extracted from pExpr */ + Expr *pExpr = pUpper->pExpr->pRight; + rc = sqlite3Stat4ProbeSetValue(pParse, p, &pRec, pExpr, aff, nEq, &bOk); + if( rc==SQLITE_OK && bOk ){ + tRowcnt iNew; + iUprIdx = whereKeyStats(pParse, p, pRec, 1, a); + iNew = a[0] + ((pUpper->eOperator & (WO_GT|WO_LE)) ? a[1] : 0); + if( iNew<iUpper ) iUpper = iNew; + nOut--; + pUpper = 0; + } } - pLoop->nOut = (LogEst)nOut; - WHERETRACE(0x10, ("range scan regions: %u..%u est=%d\n", - (u32)iLower, (u32)iUpper, nOut)); - return SQLITE_OK; + + pBuilder->pRec = pRec; + if( rc==SQLITE_OK ){ + if( iUpper>iLower ){ + nNew = sqlite3LogEst(iUpper - iLower); + /* TUNING: If both iUpper and iLower are derived from the same + ** sample, then assume they are 4x more selective. This brings + ** the estimated selectivity more in line with what it would be + ** if estimated without the use of STAT3/4 tables. */ + if( iLwrIdx==iUprIdx ) nNew -= 20; assert( 20==sqlite3LogEst(4) ); + }else{ + nNew = 10; assert( 10==sqlite3LogEst(2) ); + } + if( nNew<nOut ){ + nOut = nNew; + } + WHERETRACE(0x10, ("STAT4 range scan: %u..%u est=%d\n", + (u32)iLower, (u32)iUpper, nOut)); + } + }else{ + int bDone = 0; + rc = whereRangeSkipScanEst(pParse, pLower, pUpper, pLoop, &bDone); + if( bDone ) return rc; } } #else UNUSED_PARAMETER(pParse); UNUSED_PARAMETER(pBuilder); -#endif assert( pLower || pUpper ); +#endif assert( pUpper==0 || (pUpper->wtFlags & TERM_VNULL)==0 ); nNew = whereRangeAdjust(pLower, nOut); nNew = whereRangeAdjust(pUpper, nNew); - /* TUNING: If there is both an upper and lower limit, assume the range is + /* TUNING: If there is both an upper and lower limit and neither limit + ** has an application-defined likelihood(), assume the range is ** reduced by an additional 75%. This means that, by default, an open-ended ** range query (e.g. col > ?) is assumed to match 1/4 of the rows in the ** index. While a closed range (e.g. col BETWEEN ? AND ?) is estimated to ** match 1/64 of the index. */ - if( pLower && pUpper ) nNew -= 20; + if( pLower && pLower->truthProb>0 && pUpper && pUpper->truthProb>0 ){ + nNew -= 20; + } nOut -= (pLower!=0) + (pUpper!=0); if( nNew<10 ) nNew = 10; if( nNew<nOut ) nOut = nNew; +#if defined(WHERETRACE_ENABLED) + if( pLoop->nOut>nOut ){ + WHERETRACE(0x10,("Range scan lowers nOut from %d to %d\n", + pLoop->nOut, nOut)); + } +#endif pLoop->nOut = (LogEst)nOut; return rc; } @@ -2201,7 +2360,7 @@ static int whereEqualScanEst( int bOk; assert( nEq>=1 ); - assert( nEq<=(p->nKeyCol+1) ); + assert( nEq<=p->nColumn ); assert( p->aSample!=0 ); assert( p->nSample>0 ); assert( pBuilder->nRecValid<nEq ); @@ -2214,7 +2373,7 @@ static int whereEqualScanEst( /* This is an optimization only. The call to sqlite3Stat4ProbeSetValue() ** below would return the same value. */ - if( nEq>p->nKeyCol ){ + if( nEq>=p->nColumn ){ *pnRow = 1; return SQLITE_OK; } @@ -2276,7 +2435,7 @@ static int whereInScanEst( if( rc==SQLITE_OK ){ if( nRowEst > nRow0 ) nRowEst = nRow0; *pnRow = nRowEst; - WHERETRACE(0x10,("IN row estimate: est=%g\n", nRowEst)); + WHERETRACE(0x10,("IN row estimate: est=%d\n", nRowEst)); } assert( pBuilder->nRecValid==nRecValid ); return rc; @@ -2408,7 +2567,7 @@ static int codeEqualityTerm( } assert( pX->op==TK_IN ); iReg = iTarget; - eType = sqlite3FindInIndex(pParse, pX, 0); + eType = sqlite3FindInIndex(pParse, pX, IN_INDEX_LOOP, 0); if( eType==IN_INDEX_INDEX_DESC ){ testcase( bRev ); bRev = !bRev; @@ -2513,7 +2672,7 @@ static int codeAllEqualityTerms( pLoop = pLevel->pWLoop; assert( (pLoop->wsFlags & WHERE_VIRTUALTABLE)==0 ); nEq = pLoop->u.btree.nEq; - nSkip = pLoop->u.btree.nSkip; + nSkip = pLoop->nSkip; pIdx = pLoop->u.btree.pIndex; assert( pIdx!=0 ); @@ -2612,9 +2771,8 @@ static void explainAppendTerm( /* ** Argument pLevel describes a strategy for scanning table pTab. This -** function returns a pointer to a string buffer containing a description -** of the subset of table rows scanned by the strategy in the form of an -** SQL expression. Or, if all rows are scanned, NULL is returned. +** function appends text to pStr that describes the subset of table +** rows scanned by the strategy in the form of an SQL expression. ** ** For example, if the query: ** @@ -2624,58 +2782,49 @@ static void explainAppendTerm( ** string similar to: ** ** "a=? AND b>?" -** -** The returned pointer points to memory obtained from sqlite3DbMalloc(). -** It is the responsibility of the caller to free the buffer when it is -** no longer required. */ -static char *explainIndexRange(sqlite3 *db, WhereLoop *pLoop, Table *pTab){ +static void explainIndexRange(StrAccum *pStr, WhereLoop *pLoop, Table *pTab){ Index *pIndex = pLoop->u.btree.pIndex; u16 nEq = pLoop->u.btree.nEq; - u16 nSkip = pLoop->u.btree.nSkip; + u16 nSkip = pLoop->nSkip; int i, j; Column *aCol = pTab->aCol; i16 *aiColumn = pIndex->aiColumn; - StrAccum txt; - if( nEq==0 && (pLoop->wsFlags & (WHERE_BTM_LIMIT|WHERE_TOP_LIMIT))==0 ){ - return 0; - } - sqlite3StrAccumInit(&txt, 0, 0, SQLITE_MAX_LENGTH); - txt.db = db; - sqlite3StrAccumAppend(&txt, " (", 2); + if( nEq==0 && (pLoop->wsFlags&(WHERE_BTM_LIMIT|WHERE_TOP_LIMIT))==0 ) return; + sqlite3StrAccumAppend(pStr, " (", 2); for(i=0; i<nEq; i++){ - char *z = (i==pIndex->nKeyCol ) ? "rowid" : aCol[aiColumn[i]].zName; + char *z = aiColumn[i] < 0 ? "rowid" : aCol[aiColumn[i]].zName; if( i>=nSkip ){ - explainAppendTerm(&txt, i, z, "="); + explainAppendTerm(pStr, i, z, "="); }else{ - if( i ) sqlite3StrAccumAppend(&txt, " AND ", 5); - sqlite3StrAccumAppend(&txt, "ANY(", 4); - sqlite3StrAccumAppendAll(&txt, z); - sqlite3StrAccumAppend(&txt, ")", 1); + if( i ) sqlite3StrAccumAppend(pStr, " AND ", 5); + sqlite3XPrintf(pStr, 0, "ANY(%s)", z); } } j = i; if( pLoop->wsFlags&WHERE_BTM_LIMIT ){ - char *z = (j==pIndex->nKeyCol ) ? "rowid" : aCol[aiColumn[j]].zName; - explainAppendTerm(&txt, i++, z, ">"); + char *z = aiColumn[j] < 0 ? "rowid" : aCol[aiColumn[j]].zName; + explainAppendTerm(pStr, i++, z, ">"); } if( pLoop->wsFlags&WHERE_TOP_LIMIT ){ - char *z = (j==pIndex->nKeyCol ) ? "rowid" : aCol[aiColumn[j]].zName; - explainAppendTerm(&txt, i, z, "<"); + char *z = aiColumn[j] < 0 ? "rowid" : aCol[aiColumn[j]].zName; + explainAppendTerm(pStr, i, z, "<"); } - sqlite3StrAccumAppend(&txt, ")", 1); - return sqlite3StrAccumFinish(&txt); + sqlite3StrAccumAppend(pStr, ")", 1); } /* ** This function is a no-op unless currently processing an EXPLAIN QUERY PLAN -** command. If the query being compiled is an EXPLAIN QUERY PLAN, a single -** record is added to the output to describe the table scan strategy in -** pLevel. +** command, or if either SQLITE_DEBUG or SQLITE_ENABLE_STMT_SCANSTATUS was +** defined at compile-time. If it is not a no-op, a single OP_Explain opcode +** is added to the output to describe the table scan strategy in pLevel. +** +** If an OP_Explain opcode is added to the VM, its address is returned. +** Otherwise, if no OP_Explain is coded, zero is returned. */ -static void explainOneScan( +static int explainOneScan( Parse *pParse, /* Parse context */ SrcList *pTabList, /* Table list this loop refers to */ WhereLevel *pLevel, /* Scan to write OP_Explain opcode for */ @@ -2683,82 +2832,136 @@ static void explainOneScan( int iFrom, /* Value for "from" column of output */ u16 wctrlFlags /* Flags passed to sqlite3WhereBegin() */ ){ -#ifndef SQLITE_DEBUG + int ret = 0; +#if !defined(SQLITE_DEBUG) && !defined(SQLITE_ENABLE_STMT_SCANSTATUS) if( pParse->explain==2 ) #endif { struct SrcList_item *pItem = &pTabList->a[pLevel->iFrom]; Vdbe *v = pParse->pVdbe; /* VM being constructed */ sqlite3 *db = pParse->db; /* Database handle */ - char *zMsg; /* Text to add to EQP output */ int iId = pParse->iSelectId; /* Select id (left-most output column) */ int isSearch; /* True for a SEARCH. False for SCAN. */ WhereLoop *pLoop; /* The controlling WhereLoop object */ u32 flags; /* Flags that describe this loop */ + char *zMsg; /* Text to add to EQP output */ + StrAccum str; /* EQP output string */ + char zBuf[100]; /* Initial space for EQP output string */ pLoop = pLevel->pWLoop; flags = pLoop->wsFlags; - if( (flags&WHERE_MULTI_OR) || (wctrlFlags&WHERE_ONETABLE_ONLY) ) return; + if( (flags&WHERE_MULTI_OR) || (wctrlFlags&WHERE_ONETABLE_ONLY) ) return 0; isSearch = (flags&(WHERE_BTM_LIMIT|WHERE_TOP_LIMIT))!=0 || ((flags&WHERE_VIRTUALTABLE)==0 && (pLoop->u.btree.nEq>0)) || (wctrlFlags&(WHERE_ORDERBY_MIN|WHERE_ORDERBY_MAX)); - zMsg = sqlite3MPrintf(db, "%s", isSearch?"SEARCH":"SCAN"); + sqlite3StrAccumInit(&str, zBuf, sizeof(zBuf), SQLITE_MAX_LENGTH); + str.db = db; + sqlite3StrAccumAppendAll(&str, isSearch ? "SEARCH" : "SCAN"); if( pItem->pSelect ){ - zMsg = sqlite3MAppendf(db, zMsg, "%s SUBQUERY %d", zMsg,pItem->iSelectId); + sqlite3XPrintf(&str, 0, " SUBQUERY %d", pItem->iSelectId); }else{ - zMsg = sqlite3MAppendf(db, zMsg, "%s TABLE %s", zMsg, pItem->zName); + sqlite3XPrintf(&str, 0, " TABLE %s", pItem->zName); } if( pItem->zAlias ){ - zMsg = sqlite3MAppendf(db, zMsg, "%s AS %s", zMsg, pItem->zAlias); + sqlite3XPrintf(&str, 0, " AS %s", pItem->zAlias); } - if( (flags & (WHERE_IPK|WHERE_VIRTUALTABLE))==0 - && ALWAYS(pLoop->u.btree.pIndex!=0) - ){ - const char *zFmt; - Index *pIdx = pLoop->u.btree.pIndex; - char *zWhere = explainIndexRange(db, pLoop, pItem->pTab); + if( (flags & (WHERE_IPK|WHERE_VIRTUALTABLE))==0 ){ + const char *zFmt = 0; + Index *pIdx; + + assert( pLoop->u.btree.pIndex!=0 ); + pIdx = pLoop->u.btree.pIndex; assert( !(flags&WHERE_AUTO_INDEX) || (flags&WHERE_IDX_ONLY) ); if( !HasRowid(pItem->pTab) && IsPrimaryKeyIndex(pIdx) ){ - zFmt = zWhere ? "%s USING PRIMARY KEY%.0s%s" : "%s%.0s%s"; + if( isSearch ){ + zFmt = "PRIMARY KEY"; + } + }else if( flags & WHERE_PARTIALIDX ){ + zFmt = "AUTOMATIC PARTIAL COVERING INDEX"; }else if( flags & WHERE_AUTO_INDEX ){ - zFmt = "%s USING AUTOMATIC COVERING INDEX%.0s%s"; + zFmt = "AUTOMATIC COVERING INDEX"; }else if( flags & WHERE_IDX_ONLY ){ - zFmt = "%s USING COVERING INDEX %s%s"; + zFmt = "COVERING INDEX %s"; }else{ - zFmt = "%s USING INDEX %s%s"; + zFmt = "INDEX %s"; + } + if( zFmt ){ + sqlite3StrAccumAppend(&str, " USING ", 7); + sqlite3XPrintf(&str, 0, zFmt, pIdx->zName); + explainIndexRange(&str, pLoop, pItem->pTab); } - zMsg = sqlite3MAppendf(db, zMsg, zFmt, zMsg, pIdx->zName, zWhere); - sqlite3DbFree(db, zWhere); }else if( (flags & WHERE_IPK)!=0 && (flags & WHERE_CONSTRAINT)!=0 ){ - zMsg = sqlite3MAppendf(db, zMsg, "%s USING INTEGER PRIMARY KEY", zMsg); - + const char *zRange; if( flags&(WHERE_COLUMN_EQ|WHERE_COLUMN_IN) ){ - zMsg = sqlite3MAppendf(db, zMsg, "%s (rowid=?)", zMsg); + zRange = "(rowid=?)"; }else if( (flags&WHERE_BOTH_LIMIT)==WHERE_BOTH_LIMIT ){ - zMsg = sqlite3MAppendf(db, zMsg, "%s (rowid>? AND rowid<?)", zMsg); + zRange = "(rowid>? AND rowid<?)"; }else if( flags&WHERE_BTM_LIMIT ){ - zMsg = sqlite3MAppendf(db, zMsg, "%s (rowid>?)", zMsg); - }else if( ALWAYS(flags&WHERE_TOP_LIMIT) ){ - zMsg = sqlite3MAppendf(db, zMsg, "%s (rowid<?)", zMsg); + zRange = "(rowid>?)"; + }else{ + assert( flags&WHERE_TOP_LIMIT); + zRange = "(rowid<?)"; } + sqlite3StrAccumAppendAll(&str, " USING INTEGER PRIMARY KEY "); + sqlite3StrAccumAppendAll(&str, zRange); } #ifndef SQLITE_OMIT_VIRTUALTABLE else if( (flags & WHERE_VIRTUALTABLE)!=0 ){ - zMsg = sqlite3MAppendf(db, zMsg, "%s VIRTUAL TABLE INDEX %d:%s", zMsg, + sqlite3XPrintf(&str, 0, " VIRTUAL TABLE INDEX %d:%s", pLoop->u.vtab.idxNum, pLoop->u.vtab.idxStr); } #endif - zMsg = sqlite3MAppendf(db, zMsg, "%s", zMsg); - sqlite3VdbeAddOp4(v, OP_Explain, iId, iLevel, iFrom, zMsg, P4_DYNAMIC); +#ifdef SQLITE_EXPLAIN_ESTIMATED_ROWS + if( pLoop->nOut>=10 ){ + sqlite3XPrintf(&str, 0, " (~%llu rows)", sqlite3LogEstToInt(pLoop->nOut)); + }else{ + sqlite3StrAccumAppend(&str, " (~1 row)", 9); + } +#endif + zMsg = sqlite3StrAccumFinish(&str); + ret = sqlite3VdbeAddOp4(v, OP_Explain, iId, iLevel, iFrom, zMsg,P4_DYNAMIC); } + return ret; } #else -# define explainOneScan(u,v,w,x,y,z) +# define explainOneScan(u,v,w,x,y,z) 0 #endif /* SQLITE_OMIT_EXPLAIN */ +#ifdef SQLITE_ENABLE_STMT_SCANSTATUS +/* +** Configure the VM passed as the first argument with an +** sqlite3_stmt_scanstatus() entry corresponding to the scan used to +** implement level pLvl. Argument pSrclist is a pointer to the FROM +** clause that the scan reads data from. +** +** If argument addrExplain is not 0, it must be the address of an +** OP_Explain instruction that describes the same loop. +*/ +static void addScanStatus( + Vdbe *v, /* Vdbe to add scanstatus entry to */ + SrcList *pSrclist, /* FROM clause pLvl reads data from */ + WhereLevel *pLvl, /* Level to add scanstatus() entry for */ + int addrExplain /* Address of OP_Explain (or 0) */ +){ + const char *zObj = 0; + WhereLoop *pLoop = pLvl->pWLoop; + if( (pLoop->wsFlags & WHERE_VIRTUALTABLE)==0 && pLoop->u.btree.pIndex!=0 ){ + zObj = pLoop->u.btree.pIndex->zName; + }else{ + zObj = pSrclist->a[pLvl->iFrom].zName; + } + sqlite3VdbeScanStatus( + v, addrExplain, pLvl->addrBody, pLvl->addrVisit, pLoop->nOut, zObj + ); +} +#else +# define addScanStatus(a, b, c, d) ((void)d) +#endif + + /* ** Generate code for the start of the iLevel-th loop in the WHERE clause @@ -3059,7 +3262,7 @@ static Bitmask codeOneLoopStart( pIdx = pLoop->u.btree.pIndex; iIdxCur = pLevel->iIdxCur; - assert( nEq>=pLoop->u.btree.nSkip ); + assert( nEq>=pLoop->nSkip ); /* If this loop satisfies a sort order (pOrderBy) request that ** was passed to this function to implement a "SELECT min(x) ..." @@ -3076,7 +3279,7 @@ static Bitmask codeOneLoopStart( && pWInfo->nOBSat>0 && (pIdx->nKeyCol>nEq) ){ - assert( pLoop->u.btree.nSkip==0 ); + assert( pLoop->nSkip==0 ); bSeekPastNull = 1; nExtraReg = 1; } @@ -3293,7 +3496,7 @@ static Bitmask codeOneLoopStart( ** B: <after the loop> ** ** Added 2014-05-26: If the table is a WITHOUT ROWID table, then - ** use an ephermeral index instead of a RowSet to record the primary + ** use an ephemeral index instead of a RowSet to record the primary ** keys of the rows we have already seen. ** */ @@ -3309,6 +3512,7 @@ static Bitmask codeOneLoopStart( int iRetInit; /* Address of regReturn init */ int untestedTerms = 0; /* Some terms not completely tested */ int ii; /* Loop counter */ + u16 wctrlFlags; /* Flags for sub-WHERE clause */ Expr *pAndExpr = 0; /* An ".. AND (...)" expression */ Table *pTab = pTabItem->pTab; @@ -3343,7 +3547,7 @@ static Bitmask codeOneLoopStart( } /* Initialize the rowset register to contain NULL. An SQL NULL is - ** equivalent to an empty rowset. Or, create an ephermeral index + ** equivalent to an empty rowset. Or, create an ephemeral index ** capable of holding primary keys in the case of a WITHOUT ROWID. ** ** Also initialize regReturn to contain the address of the instruction @@ -3388,10 +3592,9 @@ static Bitmask codeOneLoopStart( Expr *pExpr = pWC->a[iTerm].pExpr; if( &pWC->a[iTerm] == pTerm ) continue; if( ExprHasProperty(pExpr, EP_FromJoin) ) continue; - testcase( pWC->a[iTerm].wtFlags & TERM_ORINFO ); - testcase( pWC->a[iTerm].wtFlags & TERM_VIRTUAL ); - if( pWC->a[iTerm].wtFlags & (TERM_ORINFO|TERM_VIRTUAL) ) continue; + if( (pWC->a[iTerm].wtFlags & TERM_VIRTUAL)!=0 ) continue; if( (pWC->a[iTerm].eOperator & WO_ALL)==0 ) continue; + testcase( pWC->a[iTerm].wtFlags & TERM_ORINFO ); pExpr = sqlite3ExprDup(db, pExpr, 0); pAndExpr = sqlite3ExprAnd(db, pAndExpr, pExpr); } @@ -3404,6 +3607,9 @@ static Bitmask codeOneLoopStart( ** eliminating duplicates from other WHERE clauses, the action for each ** sub-WHERE clause is to to invoke the main loop body as a subroutine. */ + wctrlFlags = WHERE_OMIT_OPEN_CLOSE + | WHERE_FORCE_TABLE + | WHERE_ONETABLE_ONLY; for(ii=0; ii<pOrWc->nTerm; ii++){ WhereTerm *pOrTerm = &pOrWc->a[ii]; if( pOrTerm->leftCursor==iCur || (pOrTerm->eOperator & WO_AND)!=0 ){ @@ -3415,15 +3621,17 @@ static Bitmask codeOneLoopStart( pOrExpr = pAndExpr; } /* Loop through table entries that match term pOrTerm. */ + WHERETRACE(0xffff, ("Subplan for OR-clause:\n")); pSubWInfo = sqlite3WhereBegin(pParse, pOrTab, pOrExpr, 0, 0, - WHERE_OMIT_OPEN_CLOSE | WHERE_AND_ONLY | - WHERE_FORCE_TABLE | WHERE_ONETABLE_ONLY, iCovCur); + wctrlFlags, iCovCur); assert( pSubWInfo || pParse->nErr || db->mallocFailed ); if( pSubWInfo ){ WhereLoop *pSubLoop; - explainOneScan( + int addrExplain = explainOneScan( pParse, pOrTab, &pSubWInfo->a[0], iLevel, pLevel->iFrom, 0 ); + addScanStatus(v, pOrTab, &pSubWInfo->a[0], addrExplain); + /* This is the sub-WHERE clause body. First skip over ** duplicate rows from prior sub-WHERE clauses, and record the ** rowid (or PRIMARY KEY) for the current row so that the same @@ -3508,6 +3716,7 @@ static Bitmask codeOneLoopStart( ){ assert( pSubWInfo->a[0].iIdxCur==iCovCur ); pCov = pSubLoop->u.btree.pIndex; + wctrlFlags |= WHERE_REOPEN_IDX; }else{ pCov = 0; } @@ -3553,6 +3762,10 @@ static Bitmask codeOneLoopStart( } } +#ifdef SQLITE_ENABLE_STMT_SCANSTATUS + pLevel->addrVisit = sqlite3VdbeCurrentAddr(v); +#endif + /* Insert code to test every subexpression that can be completely ** computed using the current set of tables. */ @@ -3634,21 +3847,26 @@ static Bitmask codeOneLoopStart( return pLevel->notReady; } -#if defined(WHERETRACE_ENABLED) && defined(SQLITE_ENABLE_TREE_EXPLAIN) +#ifdef WHERETRACE_ENABLED /* -** Generate "Explanation" text for a WhereTerm. +** Print the content of a WhereTerm object */ -static void whereExplainTerm(Vdbe *v, WhereTerm *pTerm){ - char zType[4]; - memcpy(zType, "...", 4); - if( pTerm->wtFlags & TERM_VIRTUAL ) zType[0] = 'V'; - if( pTerm->eOperator & WO_EQUIV ) zType[1] = 'E'; - if( ExprHasProperty(pTerm->pExpr, EP_FromJoin) ) zType[2] = 'L'; - sqlite3ExplainPrintf(v, "%s ", zType); - sqlite3ExplainExpr(v, pTerm->pExpr); +static void whereTermPrint(WhereTerm *pTerm, int iTerm){ + if( pTerm==0 ){ + sqlite3DebugPrintf("TERM-%-3d NULL\n", iTerm); + }else{ + char zType[4]; + memcpy(zType, "...", 4); + if( pTerm->wtFlags & TERM_VIRTUAL ) zType[0] = 'V'; + if( pTerm->eOperator & WO_EQUIV ) zType[1] = 'E'; + if( ExprHasProperty(pTerm->pExpr, EP_FromJoin) ) zType[2] = 'L'; + sqlite3DebugPrintf("TERM-%-3d %p %s cursor=%-3d prob=%-3d op=0x%03x\n", + iTerm, pTerm, zType, pTerm->leftCursor, pTerm->truthProb, + pTerm->eOperator); + sqlite3TreeViewExpr(0, pTerm->pExpr, 0); + } } -#endif /* WHERETRACE_ENABLED && SQLITE_ENABLE_TREE_EXPLAIN */ - +#endif #ifdef WHERETRACE_ENABLED /* @@ -3664,8 +3882,8 @@ static void whereLoopPrint(WhereLoop *p, WhereClause *pWC){ sqlite3DebugPrintf(" %12s", pItem->zAlias ? pItem->zAlias : pTab->zName); if( (p->wsFlags & WHERE_VIRTUALTABLE)==0 ){ - const char *zName; - if( p->u.btree.pIndex && (zName = p->u.btree.pIndex->zName)!=0 ){ + const char *zName; + if( p->u.btree.pIndex && (zName = p->u.btree.pIndex->zName)!=0 ){ if( strncmp(zName, "sqlite_autoindex_", 17)==0 ){ int i = sqlite3Strlen30(zName) - 1; while( zName[i]!='_' ) i--; @@ -3686,29 +3904,18 @@ static void whereLoopPrint(WhereLoop *p, WhereClause *pWC){ sqlite3DebugPrintf(" %-19s", z); sqlite3_free(z); } - sqlite3DebugPrintf(" f %05x N %d", p->wsFlags, p->nLTerm); + if( p->wsFlags & WHERE_SKIPSCAN ){ + sqlite3DebugPrintf(" f %05x %d-%d", p->wsFlags, p->nLTerm,p->nSkip); + }else{ + sqlite3DebugPrintf(" f %05x N %d", p->wsFlags, p->nLTerm); + } sqlite3DebugPrintf(" cost %d,%d,%d\n", p->rSetup, p->rRun, p->nOut); -#ifdef SQLITE_ENABLE_TREE_EXPLAIN - /* If the 0x100 bit of wheretracing is set, then show all of the constraint - ** expressions in the WhereLoop.aLTerm[] array. - */ - if( p->nLTerm && (sqlite3WhereTrace & 0x100)!=0 ){ /* WHERETRACE 0x100 */ + if( p->nLTerm && (sqlite3WhereTrace & 0x100)!=0 ){ int i; - Vdbe *v = pWInfo->pParse->pVdbe; - sqlite3ExplainBegin(v); for(i=0; i<p->nLTerm; i++){ - WhereTerm *pTerm = p->aLTerm[i]; - if( pTerm==0 ) continue; - sqlite3ExplainPrintf(v, " (%d) #%-2d ", i+1, (int)(pTerm-pWC->a)); - sqlite3ExplainPush(v); - whereExplainTerm(v, pTerm); - sqlite3ExplainPop(v); - sqlite3ExplainNL(v); + whereTermPrint(p->aLTerm[i], i); } - sqlite3ExplainFinish(v); - sqlite3DebugPrintf("%s", sqlite3VdbeExplanation(v)); } -#endif } #endif @@ -3734,7 +3941,6 @@ static void whereLoopClearUnion(sqlite3 *db, WhereLoop *p){ p->u.vtab.idxStr = 0; }else if( (p->wsFlags & WHERE_AUTO_INDEX)!=0 && p->u.btree.pIndex!=0 ){ sqlite3DbFree(db, p->u.btree.pIndex->zColAff); - sqlite3KeyInfoUnref(p->u.btree.pIndex->pKeyInfo); sqlite3DbFree(db, p->u.btree.pIndex); p->u.btree.pIndex = 0; } @@ -3809,10 +4015,11 @@ static void whereInfoFree(sqlite3 *db, WhereInfo *pWInfo){ } /* -** Return TRUE if both of the following are true: +** Return TRUE if all of the following are true: ** ** (1) X has the same or lower cost that Y ** (2) X is a proper subset of Y +** (3) X skips at least as many columns as Y ** ** By "proper subset" we mean that X uses fewer WHERE clause terms ** than Y and that every WHERE clause term used by X is also used @@ -3820,19 +4027,25 @@ static void whereInfoFree(sqlite3 *db, WhereInfo *pWInfo){ ** ** If X is a proper subset of Y then Y is a better choice and ought ** to have a lower cost. This routine returns TRUE when that cost -** relationship is inverted and needs to be adjusted. +** relationship is inverted and needs to be adjusted. The third rule +** was added because if X uses skip-scan less than Y it still might +** deserve a lower cost even if it is a proper subset of Y. */ static int whereLoopCheaperProperSubset( const WhereLoop *pX, /* First WhereLoop to compare */ const WhereLoop *pY /* Compare against this WhereLoop */ ){ int i, j; - if( pX->nLTerm >= pY->nLTerm ) return 0; /* X is not a subset of Y */ + if( pX->nLTerm-pX->nSkip >= pY->nLTerm-pY->nSkip ){ + return 0; /* X is not a subset of Y */ + } + if( pY->nSkip > pX->nSkip ) return 0; if( pX->rRun >= pY->rRun ){ if( pX->rRun > pY->rRun ) return 0; /* X costs more than Y */ if( pX->nOut > pY->nOut ) return 0; /* X costs more than Y */ } for(i=pX->nLTerm-1; i>=0; i--){ + if( pX->aLTerm[i]==0 ) continue; for(j=pY->nLTerm-1; j>=0; j--){ if( pY->aLTerm[j]==pX->aLTerm[i] ) break; } @@ -3854,33 +4067,24 @@ static int whereLoopCheaperProperSubset( ** To say "WhereLoop X is a proper subset of Y" means that X uses fewer ** WHERE clause terms than Y and that every WHERE clause term used by X is ** also used by Y. -** -** This adjustment is omitted for SKIPSCAN loops. In a SKIPSCAN loop, the -** WhereLoop.nLTerm field is not an accurate measure of the number of WHERE -** clause terms covered, since some of the first nLTerm entries in aLTerm[] -** will be NULL (because they are skipped). That makes it more difficult -** to compare the loops. We could add extra code to do the comparison, and -** perhaps we will someday. But SKIPSCAN is sufficiently uncommon, and this -** adjustment is sufficient minor, that it is very difficult to construct -** a test case where the extra code would improve the query plan. Better -** to avoid the added complexity and just omit cost adjustments to SKIPSCAN -** loops. */ static void whereLoopAdjustCost(const WhereLoop *p, WhereLoop *pTemplate){ if( (pTemplate->wsFlags & WHERE_INDEXED)==0 ) return; - if( (pTemplate->wsFlags & WHERE_SKIPSCAN)!=0 ) return; for(; p; p=p->pNextLoop){ if( p->iTab!=pTemplate->iTab ) continue; if( (p->wsFlags & WHERE_INDEXED)==0 ) continue; - if( (p->wsFlags & WHERE_SKIPSCAN)!=0 ) continue; if( whereLoopCheaperProperSubset(p, pTemplate) ){ /* Adjust pTemplate cost downward so that it is cheaper than its - ** subset p */ + ** 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; } @@ -3925,8 +4129,9 @@ static WhereLoop **whereLoopFindLesser( /* Any loop using an appliation-defined index (or PRIMARY KEY or ** UNIQUE constraint) with one or more == constraints is better - ** than an automatic index. */ + ** than an automatic index. Unless it is a skip-scan. */ if( (p->wsFlags & WHERE_AUTO_INDEX)!=0 + && (pTemplate->nSkip)==0 && (pTemplate->wsFlags & WHERE_INDEXED)!=0 && (pTemplate->wsFlags & WHERE_COLUMN_EQ)!=0 && (p->prereq & pTemplate->prereq)==pTemplate->prereq @@ -4021,7 +4226,7 @@ static int whereLoopInsert(WhereLoopBuilder *pBuilder, WhereLoop *pTemplate){ ** than pTemplate, so just ignore pTemplate */ #if WHERETRACE_ENABLED /* 0x8 */ if( sqlite3WhereTrace & 0x8 ){ - sqlite3DebugPrintf("ins-noop: "); + sqlite3DebugPrintf(" skip: "); whereLoopPrint(pTemplate, pBuilder->pWC); } #endif @@ -4037,10 +4242,10 @@ static int whereLoopInsert(WhereLoopBuilder *pBuilder, WhereLoop *pTemplate){ #if WHERETRACE_ENABLED /* 0x8 */ if( sqlite3WhereTrace & 0x8 ){ if( p!=0 ){ - sqlite3DebugPrintf("ins-del: "); + sqlite3DebugPrintf("replace: "); whereLoopPrint(p, pBuilder->pWC); } - sqlite3DebugPrintf("ins-new: "); + sqlite3DebugPrintf(" add: "); whereLoopPrint(pTemplate, pBuilder->pWC); } #endif @@ -4064,7 +4269,7 @@ static int whereLoopInsert(WhereLoopBuilder *pBuilder, WhereLoop *pTemplate){ *ppTail = pToDel->pNextLoop; #if WHERETRACE_ENABLED /* 0x8 */ if( sqlite3WhereTrace & 0x8 ){ - sqlite3DebugPrintf("ins-del: "); + sqlite3DebugPrintf(" delete: "); whereLoopPrint(pToDel, pBuilder->pWC); } #endif @@ -4085,19 +4290,42 @@ static int whereLoopInsert(WhereLoopBuilder *pBuilder, WhereLoop *pTemplate){ ** Adjust the WhereLoop.nOut value downward to account for terms of the ** WHERE clause that reference the loop but which are not used by an ** index. -** -** In the current implementation, the first extra WHERE clause term reduces -** the number of output rows by a factor of 10 and each additional term -** reduces the number of output rows by sqrt(2). +* +** For every WHERE clause term that is not used by the index +** and which has a truth probability assigned by one of the likelihood(), +** likely(), or unlikely() SQL functions, reduce the estimated number +** of output rows by the probability specified. +** +** TUNING: For every WHERE clause term that is not used by the index +** and which does not have an assigned truth probability, heuristics +** described below are used to try to estimate the truth probability. +** TODO --> Perhaps this is something that could be improved by better +** table statistics. +** +** Heuristic 1: Estimate the truth probability as 93.75%. The 93.75% +** value corresponds to -1 in LogEst notation, so this means decrement +** the WhereLoop.nOut field for every such WHERE clause term. +** +** Heuristic 2: If there exists one or more WHERE clause terms of the +** form "x==EXPR" and EXPR is not a constant 0 or 1, then make sure the +** final output row estimate is no greater than 1/4 of the total number +** of rows in the table. In other words, assume that x==EXPR will filter +** out at least 3 out of 4 rows. If EXPR is -1 or 0 or 1, then maybe the +** "x" column is boolean or else -1 or 0 or 1 is a common default value +** on the "x" column and so in that case only cap the output row estimate +** at 1/2 instead of 1/4. */ -static void whereLoopOutputAdjust(WhereClause *pWC, WhereLoop *pLoop){ +static void whereLoopOutputAdjust( + WhereClause *pWC, /* The WHERE clause */ + WhereLoop *pLoop, /* The loop to adjust downward */ + LogEst nRow /* Number of rows in the entire table */ +){ WhereTerm *pTerm, *pX; Bitmask notAllowed = ~(pLoop->prereq|pLoop->maskSelf); - int i, j; + int i, j, k; + LogEst iReduce = 0; /* pLoop->nOut should not exceed nRow-iReduce */ - if( !OptimizationEnabled(pWC->pWInfo->pParse->db, SQLITE_AdjustOutEst) ){ - return; - } + assert( (pLoop->wsFlags & WHERE_AUTO_INDEX)==0 ); for(i=pWC->nTerm, pTerm=pWC->a; i>0; i--, pTerm++){ if( (pTerm->wtFlags & TERM_VIRTUAL)!=0 ) break; if( (pTerm->prereqAll & pLoop->maskSelf)==0 ) continue; @@ -4109,12 +4337,40 @@ static void whereLoopOutputAdjust(WhereClause *pWC, WhereLoop *pLoop){ if( pX->iParent>=0 && (&pWC->a[pX->iParent])==pTerm ) break; } if( j<0 ){ - pLoop->nOut += (pTerm->truthProb<=0 ? pTerm->truthProb : -1); + if( pTerm->truthProb<=0 ){ + /* If a truth probability is specified using the likelihood() hints, + ** then use the probability provided by the application. */ + pLoop->nOut += pTerm->truthProb; + }else{ + /* In the absence of explicit truth probabilities, use heuristics to + ** guess a reasonable truth probability. */ + pLoop->nOut--; + if( pTerm->eOperator&WO_EQ ){ + Expr *pRight = pTerm->pExpr->pRight; + if( sqlite3ExprIsInteger(pRight, &k) && k>=(-1) && k<=1 ){ + k = 10; + }else{ + k = 20; + } + if( iReduce<k ) iReduce = k; + } + } } } + if( pLoop->nOut > nRow-iReduce ) pLoop->nOut = nRow - iReduce; } /* +** Adjust the cost C by the costMult facter T. This only occurs if +** compiled with -DSQLITE_ENABLE_COSTMULT +*/ +#ifdef SQLITE_ENABLE_COSTMULT +# define ApplyCostMultiplier(C,T) C += T +#else +# define ApplyCostMultiplier(C,T) +#endif + +/* ** We have so far matched pBuilder->pNew->u.btree.nEq terms of the ** index pIndex. Try to match one more. ** @@ -4142,11 +4398,12 @@ static int whereLoopAddBtreeIndex( Bitmask saved_prereq; /* Original value of pNew->prereq */ u16 saved_nLTerm; /* Original value of pNew->nLTerm */ u16 saved_nEq; /* Original value of pNew->u.btree.nEq */ - u16 saved_nSkip; /* Original value of pNew->u.btree.nSkip */ + u16 saved_nSkip; /* Original value of pNew->nSkip */ u32 saved_wsFlags; /* Original value of pNew->wsFlags */ LogEst saved_nOut; /* Original value of pNew->nOut */ int iCol; /* Index of the column in the table */ int rc = SQLITE_OK; /* Return code */ + LogEst rSize; /* Number of rows in the table */ LogEst rLogSize; /* Logarithm of table size */ WhereTerm *pTop = 0, *pBtm = 0; /* Top and bottom range constraints */ @@ -4164,50 +4421,20 @@ static int whereLoopAddBtreeIndex( } if( pProbe->bUnordered ) opMask &= ~(WO_GT|WO_GE|WO_LT|WO_LE); - assert( pNew->u.btree.nEq<=pProbe->nKeyCol ); - if( pNew->u.btree.nEq < pProbe->nKeyCol ){ - iCol = pProbe->aiColumn[pNew->u.btree.nEq]; - }else{ - iCol = -1; - } + assert( pNew->u.btree.nEq<pProbe->nColumn ); + iCol = pProbe->aiColumn[pNew->u.btree.nEq]; + pTerm = whereScanInit(&scan, pBuilder->pWC, pSrc->iCursor, iCol, opMask, pProbe); saved_nEq = pNew->u.btree.nEq; - saved_nSkip = pNew->u.btree.nSkip; + saved_nSkip = pNew->nSkip; saved_nLTerm = pNew->nLTerm; saved_wsFlags = pNew->wsFlags; saved_prereq = pNew->prereq; saved_nOut = pNew->nOut; pNew->rSetup = 0; - rLogSize = estLog(pProbe->aiRowLogEst[0]); - - /* Consider using a skip-scan if there are no WHERE clause constraints - ** available for the left-most terms of the index, and if the average - ** number of repeats in the left-most terms is at least 18. - ** - ** The magic number 18 is selected on the basis that scanning 17 rows - ** is almost always quicker than an index seek (even though if the index - ** contains fewer than 2^17 rows we assume otherwise in other parts of - ** the code). And, even if it is not, it should not be too much slower. - ** On the other hand, the extra seeks could end up being significantly - ** more expensive. */ - assert( 42==sqlite3LogEst(18) ); - if( pTerm==0 - && saved_nEq==saved_nSkip - && saved_nEq+1<pProbe->nKeyCol - && pProbe->aiRowLogEst[saved_nEq+1]>=42 /* TUNING: Minimum for skip-scan */ - && (rc = whereLoopResize(db, pNew, pNew->nLTerm+1))==SQLITE_OK - ){ - LogEst nIter; - pNew->u.btree.nEq++; - pNew->u.btree.nSkip++; - pNew->aLTerm[pNew->nLTerm++] = 0; - pNew->wsFlags |= WHERE_SKIPSCAN; - nIter = pProbe->aiRowLogEst[saved_nEq] - pProbe->aiRowLogEst[saved_nEq+1]; - pNew->nOut -= nIter; - whereLoopAddBtreeIndex(pBuilder, pSrc, pProbe, nIter + nInMul); - pNew->nOut = saved_nOut; - } + rSize = pProbe->aiRowLogEst[0]; + rLogSize = estLog(rSize); for(; rc==SQLITE_OK && pTerm!=0; pTerm = whereScanNext(&scan)){ u16 eOp = pTerm->eOperator; /* Shorthand for pTerm->eOperator */ LogEst rCostIdx; @@ -4252,7 +4479,7 @@ static int whereLoopAddBtreeIndex( }else if( eOp & (WO_EQ) ){ pNew->wsFlags |= WHERE_COLUMN_EQ; if( iCol<0 || (nInMul==0 && pNew->u.btree.nEq==pProbe->nKeyCol-1) ){ - if( iCol>=0 && pProbe->onError==OE_None ){ + if( iCol>=0 && !IsUniqueIndex(pProbe) ){ pNew->wsFlags |= WHERE_UNQ_WANTED; }else{ pNew->wsFlags |= WHERE_ONEROW; @@ -4302,7 +4529,6 @@ static int whereLoopAddBtreeIndex( if( nInMul==0 && pProbe->nSample && pNew->u.btree.nEq<=pProbe->nSampleCol - && OptimizationEnabled(db, SQLITE_Stat3) && ((eOp & WO_IN)==0 || !ExprHasProperty(pTerm->pExpr, EP_xIsSelect)) ){ Expr *pExpr = pTerm->pExpr; @@ -4313,7 +4539,6 @@ static int whereLoopAddBtreeIndex( }else{ rc = whereInScanEst(pParse, pBuilder, pExpr->x.pList, &nOut); } - assert( rc!=SQLITE_OK || nOut>0 ); if( rc==SQLITE_NOTFOUND ) rc = SQLITE_OK; if( rc!=SQLITE_OK ) break; /* Jump out of the pTerm loop */ if( nOut ){ @@ -4345,11 +4570,12 @@ static int whereLoopAddBtreeIndex( if( (pNew->wsFlags & (WHERE_IDX_ONLY|WHERE_IPK))==0 ){ pNew->rRun = sqlite3LogEstAdd(pNew->rRun, pNew->nOut + 16); } + ApplyCostMultiplier(pNew->rRun, pProbe->pTable->costMult); nOutUnadjusted = pNew->nOut; pNew->rRun += nInMul + nIn; pNew->nOut += nInMul + nIn; - whereLoopOutputAdjust(pBuilder->pWC, pNew); + whereLoopOutputAdjust(pBuilder->pWC, pNew, rSize); rc = whereLoopInsert(pBuilder, pNew); if( pNew->wsFlags & WHERE_COLUMN_RANGE ){ @@ -4359,7 +4585,7 @@ static int whereLoopAddBtreeIndex( } if( (pNew->wsFlags & WHERE_TOP_LIMIT)==0 - && pNew->u.btree.nEq<(pProbe->nKeyCol + (pProbe->zName!=0)) + && pNew->u.btree.nEq<pProbe->nColumn ){ whereLoopAddBtreeIndex(pBuilder, pSrc, pProbe, nInMul+nIn); } @@ -4370,10 +4596,45 @@ static int whereLoopAddBtreeIndex( } pNew->prereq = saved_prereq; pNew->u.btree.nEq = saved_nEq; - pNew->u.btree.nSkip = saved_nSkip; + pNew->nSkip = saved_nSkip; pNew->wsFlags = saved_wsFlags; pNew->nOut = saved_nOut; pNew->nLTerm = saved_nLTerm; + + /* Consider using a skip-scan if there are no WHERE clause constraints + ** available for the left-most terms of the index, and if the average + ** number of repeats in the left-most terms is at least 18. + ** + ** The magic number 18 is selected on the basis that scanning 17 rows + ** is almost always quicker than an index seek (even though if the index + ** contains fewer than 2^17 rows we assume otherwise in other parts of + ** the code). And, even if it is not, it should not be too much slower. + ** On the other hand, the extra seeks could end up being significantly + ** more expensive. */ + assert( 42==sqlite3LogEst(18) ); + if( saved_nEq==saved_nSkip + && saved_nEq+1<pProbe->nKeyCol + && pProbe->noSkipScan==0 + && pProbe->aiRowLogEst[saved_nEq+1]>=42 /* TUNING: Minimum for skip-scan */ + && (rc = whereLoopResize(db, pNew, pNew->nLTerm+1))==SQLITE_OK + ){ + LogEst nIter; + pNew->u.btree.nEq++; + pNew->nSkip++; + pNew->aLTerm[pNew->nLTerm++] = 0; + pNew->wsFlags |= WHERE_SKIPSCAN; + nIter = pProbe->aiRowLogEst[saved_nEq] - pProbe->aiRowLogEst[saved_nEq+1]; + pNew->nOut -= nIter; + /* TUNING: Because uncertainties in the estimates for skip-scan queries, + ** add a 1.375 fudge factor to make skip-scan slightly less likely. */ + nIter += 5; + whereLoopAddBtreeIndex(pBuilder, pSrc, pProbe, nIter + nInMul); + pNew->nOut = saved_nOut; + pNew->u.btree.nEq = saved_nEq; + pNew->nSkip = saved_nSkip; + pNew->wsFlags = saved_wsFlags; + } + return rc; } @@ -4399,6 +4660,7 @@ static int indexMightHelpWithOrderBy( Expr *pExpr = sqlite3ExprSkipCollate(pOB->a[ii].pExpr); if( pExpr->op!=TK_COLUMN ) return 0; if( pExpr->iTable==iCursor ){ + if( pExpr->iColumn<0 ) return 1; for(jj=0; jj<pIndex->nKeyCol; jj++){ if( pExpr->iColumn==pIndex->aiColumn[jj] ) return 1; } @@ -4464,6 +4726,14 @@ static int whereUsablePartialIndex(int iTab, WhereClause *pWC, Expr *pWhere){ ** Normally, nSeek is 1. nSeek values greater than 1 come about if the ** WHERE clause includes "x IN (....)" terms used in place of "x=?". Or when ** implicit "x IN (SELECT x FROM tbl)" terms are added for skip-scans. +** +** The estimated values (nRow, nVisit, nSeek) often contain a large amount +** of uncertainty. For this reason, scoring is designed to pick plans that +** "do the least harm" if the estimates are inaccurate. For example, a +** log(nRow) factor is omitted from a non-covering index scan in order to +** bias the scoring in favor of using an index, since the worst-case +** performance of using an index is far better than the worst-case performance +** of a full table scan. */ static int whereLoopAddBtree( WhereLoopBuilder *pBuilder, /* WHERE clause information */ @@ -4506,6 +4776,7 @@ static int whereLoopAddBtree( Index *pFirst; /* First of real indices on the table */ memset(&sPk, 0, sizeof(Index)); sPk.nKeyCol = 1; + sPk.nColumn = 1; sPk.aiColumn = &aiColumnPk; sPk.aiRowLogEst = aiRowEstPk; sPk.onError = OE_Replace; @@ -4542,17 +4813,26 @@ static int whereLoopAddBtree( if( pTerm->prereqRight & pNew->maskSelf ) continue; if( termCanDriveIndex(pTerm, pSrc, 0) ){ pNew->u.btree.nEq = 1; - pNew->u.btree.nSkip = 0; + pNew->nSkip = 0; pNew->u.btree.pIndex = 0; pNew->nLTerm = 1; pNew->aLTerm[0] = pTerm; /* TUNING: One-time cost for computing the automatic index is - ** approximately 7*N*log2(N) where N is the number of rows in - ** the table being indexed. */ - pNew->rSetup = rLogSize + rSize + 28; assert( 28==sqlite3LogEst(7) ); + ** estimated to be X*N*log2(N) where N is the number of rows in + ** the table being indexed and where X is 7 (LogEst=28) for normal + ** tables or 1.375 (LogEst=4) for views and subqueries. The value + ** of X is smaller for views and subqueries so that the query planner + ** will be more aggressive about generating automatic indexes for + ** those objects, since there is no opportunity to add schema + ** indexes on subqueries and views. */ + pNew->rSetup = rLogSize + rSize + 4; + if( pTab->pSelect==0 && (pTab->tabFlags & TF_Ephemeral)==0 ){ + pNew->rSetup += 24; + } + ApplyCostMultiplier(pNew->rSetup, pTab->costMult); /* TUNING: Each index lookup yields 20 rows in the table. This ** is more than the usual guess of 10 rows, since we have no way - ** of knowning how selective the index will ultimately be. It would + ** of knowing how selective the index will ultimately be. It would ** not be unreasonable to make this value much larger. */ pNew->nOut = 43; assert( 43==sqlite3LogEst(20) ); pNew->rRun = sqlite3LogEstAdd(rLogSize,pNew->nOut); @@ -4568,12 +4848,13 @@ static int whereLoopAddBtree( */ for(; rc==SQLITE_OK && pProbe; pProbe=pProbe->pNext, iSortIdx++){ if( pProbe->pPartIdxWhere!=0 - && !whereUsablePartialIndex(pNew->iTab, pWC, pProbe->pPartIdxWhere) ){ + && !whereUsablePartialIndex(pSrc->iCursor, pWC, pProbe->pPartIdxWhere) ){ + testcase( pNew->iTab!=pSrc->iCursor ); /* See ticket [98d973b8f5] */ continue; /* Partial index inappropriate for this query */ } rSize = pProbe->aiRowLogEst[0]; pNew->u.btree.nEq = 0; - pNew->u.btree.nSkip = 0; + pNew->nSkip = 0; pNew->nLTerm = 0; pNew->iSortIdx = 0; pNew->rSetup = 0; @@ -4591,7 +4872,8 @@ static int whereLoopAddBtree( pNew->iSortIdx = b ? iSortIdx : 0; /* TUNING: Cost of full table scan is (N*3.0). */ pNew->rRun = rSize + 16; - whereLoopOutputAdjust(pWC, pNew); + ApplyCostMultiplier(pNew->rRun, pTab->costMult); + whereLoopOutputAdjust(pWC, pNew, rSize); rc = whereLoopInsert(pBuilder, pNew); pNew->nOut = rSize; if( rc ) break; @@ -4626,8 +4908,8 @@ static int whereLoopAddBtree( if( m!=0 ){ pNew->rRun = sqlite3LogEstAdd(pNew->rRun, rSize+16); } - - whereLoopOutputAdjust(pWC, pNew); + ApplyCostMultiplier(pNew->rRun, pTab->costMult); + whereLoopOutputAdjust(pWC, pNew, rSize); rc = whereLoopInsert(pBuilder, pNew); pNew->nOut = rSize; if( rc ) break; @@ -4834,7 +5116,6 @@ static int whereLoopAddOr(WhereLoopBuilder *pBuilder, Bitmask mExtra){ struct SrcList_item *pItem; pWC = pBuilder->pWC; - if( pWInfo->wctrlFlags & WHERE_AND_ONLY ) return SQLITE_OK; pWCEnd = pWC->a + pWC->nTerm; pNew = pBuilder->pNew; memset(&sSum, 0, sizeof(sSum)); @@ -4855,6 +5136,7 @@ static int whereLoopAddOr(WhereLoopBuilder *pBuilder, Bitmask mExtra){ sSubBuild.pOrderBy = 0; sSubBuild.pOrSet = &sCur; + WHERETRACE(0x200, ("Begin processing OR-clause %p\n", pTerm)); for(pOrTerm=pOrWC->a; pOrTerm<pOrWCEnd; pOrTerm++){ if( (pOrTerm->eOperator & WO_AND)!=0 ){ sSubBuild.pWC = &pOrTerm->u.pAndInfo->wc; @@ -4869,6 +5151,15 @@ static int whereLoopAddOr(WhereLoopBuilder *pBuilder, Bitmask mExtra){ continue; } sCur.n = 0; +#ifdef WHERETRACE_ENABLED + WHERETRACE(0x200, ("OR-term %d of %p has %d subterms:\n", + (int)(pOrTerm-pOrWC->a), pTerm, sSubBuild.pWC->nTerm)); + if( sqlite3WhereTrace & 0x400 ){ + for(i=0; i<sSubBuild.pWC->nTerm; i++){ + whereTermPrint(&sSubBuild.pWC->a[i], i); + } + } +#endif #ifndef SQLITE_OMIT_VIRTUALTABLE if( IsVirtual(pItem->pTab) ){ rc = whereLoopAddVirtual(&sSubBuild, mExtra); @@ -4877,6 +5168,9 @@ static int whereLoopAddOr(WhereLoopBuilder *pBuilder, Bitmask mExtra){ { rc = whereLoopAddBtree(&sSubBuild, mExtra); } + if( rc==SQLITE_OK ){ + rc = whereLoopAddOr(&sSubBuild, mExtra); + } assert( rc==SQLITE_OK || sCur.n==0 ); if( sCur.n==0 ){ sSum.n = 0; @@ -4921,6 +5215,7 @@ static int whereLoopAddOr(WhereLoopBuilder *pBuilder, Bitmask mExtra){ pNew->prereq = sSum.a[i].prereq; rc = whereLoopInsert(pBuilder, pNew); } + WHERETRACE(0x200, ("End processing OR-clause %p\n", pTerm)); } } return rc; @@ -4980,7 +5275,7 @@ static int whereLoopAddAll(WhereLoopBuilder *pBuilder){ ** strict. With GROUP BY and DISTINCT the only requirement is that ** equivalent rows appear immediately adjacent to one another. GROUP BY ** and DISTINCT do not require rows to appear in any particular order as long -** as equivelent rows are grouped together. Thus for GROUP BY and DISTINCT +** as equivalent rows are grouped together. Thus for GROUP BY and DISTINCT ** the pOrderBy terms can be matched in any order. With ORDER BY, the ** pOrderBy terms must be matched in strict left-to-right order. */ @@ -5096,7 +5391,7 @@ static i8 wherePathSatisfiesOrderBy( nColumn = pIndex->nColumn; assert( nColumn==nKeyCol+1 || !HasRowid(pIndex->pTable) ); assert( pIndex->aiColumn[nColumn-1]==(-1) || !HasRowid(pIndex->pTable)); - isOrderDistinct = pIndex->onError!=OE_None; + isOrderDistinct = IsUniqueIndex(pIndex); } /* Loop through all columns of the index and deal with the ones @@ -5109,7 +5404,7 @@ static i8 wherePathSatisfiesOrderBy( /* Skip over == and IS NULL terms */ if( j<pLoop->u.btree.nEq - && pLoop->u.btree.nSkip==0 + && pLoop->nSkip==0 && ((i = pLoop->aLTerm[j]->eOperator) & (WO_EQ|WO_ISNULL))!=0 ){ if( i & WO_ISNULL ){ @@ -5164,7 +5459,7 @@ static i8 wherePathSatisfiesOrderBy( isMatch = 1; break; } - if( isMatch && (pWInfo->wctrlFlags & WHERE_GROUPBY)==0 ){ + if( isMatch && (wctrlFlags & WHERE_GROUPBY)==0 ){ /* Make sure the sort order is compatible in an ORDER BY clause. ** Sort order is irrelevant for a GROUP BY clause. */ if( revSet ){ @@ -5266,6 +5561,45 @@ static const char *wherePathName(WherePath *pPath, int nLoop, WhereLoop *pLast){ #endif /* +** Return the cost of sorting nRow rows, assuming that the keys have +** nOrderby columns and that the first nSorted columns are already in +** order. +*/ +static LogEst whereSortingCost( + WhereInfo *pWInfo, + LogEst nRow, + int nOrderBy, + int nSorted +){ + /* TUNING: Estimated cost of a full external sort, where N is + ** the number of rows to sort is: + ** + ** cost = (3.0 * N * log(N)). + ** + ** Or, if the order-by clause has X terms but only the last Y + ** terms are out of order, then block-sorting will reduce the + ** sorting cost to: + ** + ** cost = (3.0 * N * log(N)) * (Y/X) + ** + ** The (Y/X) term is implemented using stack variable rScale + ** below. */ + LogEst rScale, rSortCost; + assert( nOrderBy>0 && 66==sqlite3LogEst(100) ); + rScale = sqlite3LogEst((nOrderBy-nSorted)*100/nOrderBy) - 66; + rSortCost = nRow + estLog(nRow) + rScale + 16; + + /* TUNING: The cost of implementing DISTINCT using a B-TREE is + ** similar but with a larger constant of proportionality. + ** Multiply by an additional factor of 3.0. */ + if( pWInfo->wctrlFlags & WHERE_WANT_DISTINCT ){ + rSortCost += 16; + } + + return rSortCost; +} + +/* ** Given the list of WhereLoop objects at pWInfo->pLoops, this routine ** attempts to find the lowest cost path that visits each WhereLoop ** once. This path is then loaded into the pWInfo->a[].pWLoop fields. @@ -5286,9 +5620,8 @@ static int wherePathSolver(WhereInfo *pWInfo, LogEst nRowEst){ int ii, jj; /* Loop counters */ int mxI = 0; /* Index of next entry to replace */ int nOrderBy; /* Number of ORDER BY clause terms */ - LogEst rCost; /* Cost of a path */ - LogEst nOut; /* Number of outputs */ LogEst mxCost = 0; /* Maximum cost of a set of paths */ + LogEst mxUnsorted = 0; /* Maximum unsorted cost of a set of path */ int nTo, nFrom; /* Number of valid entries in aTo[] and aFrom[] */ WherePath *aFrom; /* All nFrom paths at the previous level */ WherePath *aTo; /* The nTo best paths at the current level */ @@ -5296,7 +5629,9 @@ static int wherePathSolver(WhereInfo *pWInfo, LogEst nRowEst){ WherePath *pTo; /* An element of aTo[] that we are working on */ WhereLoop *pWLoop; /* One of the WhereLoop objects */ WhereLoop **pX; /* Used to divy up the pSpace memory */ + LogEst *aSortCost = 0; /* Sorting and partial sorting costs */ char *pSpace; /* Temporary memory used by this routine */ + int nSpace; /* Bytes of space allocated at pSpace */ pParse = pWInfo->pParse; db = pParse->db; @@ -5306,11 +5641,23 @@ static int wherePathSolver(WhereInfo *pWInfo, LogEst nRowEst){ ** For joins of 3 or more tables, track the 10 best paths */ mxChoice = (nLoop<=1) ? 1 : (nLoop==2 ? 5 : 10); assert( nLoop<=pWInfo->pTabList->nSrc ); - WHERETRACE(0x002, ("---- begin solver\n")); + WHERETRACE(0x002, ("---- begin solver. (nRowEst=%d)\n", nRowEst)); + + /* If nRowEst is zero and there is an ORDER BY clause, ignore it. In this + ** case the purpose of this call is to estimate the number of rows returned + ** by the overall query. Once this estimate has been obtained, the caller + ** will invoke this function a second time, passing the estimate as the + ** nRowEst parameter. */ + if( pWInfo->pOrderBy==0 || nRowEst==0 ){ + nOrderBy = 0; + }else{ + nOrderBy = pWInfo->pOrderBy->nExpr; + } - /* Allocate and initialize space for aTo and aFrom */ - ii = (sizeof(WherePath)+sizeof(WhereLoop*)*nLoop)*mxChoice*2; - pSpace = sqlite3DbMallocRaw(db, ii); + /* Allocate and initialize space for aTo, aFrom and aSortCost[] */ + nSpace = (sizeof(WherePath)+sizeof(WhereLoop*)*nLoop)*mxChoice*2; + nSpace += sizeof(LogEst) * nOrderBy; + pSpace = sqlite3DbMallocRaw(db, nSpace); if( pSpace==0 ) return SQLITE_NOMEM; aTo = (WherePath*)pSpace; aFrom = aTo+mxChoice; @@ -5319,6 +5666,18 @@ static int wherePathSolver(WhereInfo *pWInfo, LogEst nRowEst){ for(ii=mxChoice*2, pFrom=aTo; ii>0; ii--, pFrom++, pX += nLoop){ pFrom->aLoop = pX; } + if( nOrderBy ){ + /* If there is an ORDER BY clause and it is not being ignored, set up + ** space for the aSortCost[] array. Each element of the aSortCost array + ** is either zero - meaning it has not yet been initialized - or the + ** cost of sorting nRowEst rows of data where the first X terms of + ** the ORDER BY clause are already in order, where X is the array + ** index. */ + aSortCost = (LogEst*)pX; + memset(aSortCost, 0, sizeof(LogEst) * nOrderBy); + } + assert( aSortCost==0 || &pSpace[nSpace]==(char*)&aSortCost[nOrderBy] ); + assert( aSortCost!=0 || &pSpace[nSpace]==(char*)pX ); /* Seed the search with a single WherePath containing zero WhereLoops. ** @@ -5327,15 +5686,15 @@ static int wherePathSolver(WhereInfo *pWInfo, LogEst nRowEst){ ** rows, then do not use the automatic index. */ aFrom[0].nRow = MIN(pParse->nQueryLoop, 46); assert( 46==sqlite3LogEst(25) ); nFrom = 1; - - /* Precompute the cost of sorting the final result set, if the caller - ** to sqlite3WhereBegin() was concerned about sorting */ - if( pWInfo->pOrderBy==0 || nRowEst==0 ){ - aFrom[0].isOrdered = 0; - nOrderBy = 0; - }else{ - aFrom[0].isOrdered = nLoop>0 ? -1 : 1; - nOrderBy = pWInfo->pOrderBy->nExpr; + assert( aFrom[0].isOrdered==0 ); + if( nOrderBy ){ + /* If nLoop is zero, then there are no FROM terms in the query. Since + ** in this case the query may return a maximum of one row, the results + ** are already in the requested order. Set isOrdered to nOrderBy to + ** indicate this. Or, if nLoop is greater than zero, set isOrdered to + ** -1, indicating that the result set may or may not be ordered, + ** depending on the loops added to the current plan. */ + aFrom[0].isOrdered = nLoop>0 ? -1 : nOrderBy; } /* Compute successively longer WherePaths using the previous generation @@ -5345,66 +5704,71 @@ static int wherePathSolver(WhereInfo *pWInfo, LogEst nRowEst){ nTo = 0; for(ii=0, pFrom=aFrom; ii<nFrom; ii++, pFrom++){ for(pWLoop=pWInfo->pLoops; pWLoop; pWLoop=pWLoop->pNextLoop){ - Bitmask maskNew; - Bitmask revMask = 0; - i8 isOrdered = pFrom->isOrdered; + LogEst nOut; /* Rows visited by (pFrom+pWLoop) */ + LogEst rCost; /* Cost of path (pFrom+pWLoop) */ + LogEst rUnsorted; /* Unsorted cost of (pFrom+pWLoop) */ + i8 isOrdered = pFrom->isOrdered; /* isOrdered for (pFrom+pWLoop) */ + Bitmask maskNew; /* Mask of src visited by (..) */ + Bitmask revMask = 0; /* Mask of rev-order loops for (..) */ + if( (pWLoop->prereq & ~pFrom->maskLoop)!=0 ) continue; if( (pWLoop->maskSelf & pFrom->maskLoop)!=0 ) continue; /* At this point, pWLoop is a candidate to be the next loop. ** Compute its cost */ - rCost = sqlite3LogEstAdd(pWLoop->rSetup,pWLoop->rRun + pFrom->nRow); - rCost = sqlite3LogEstAdd(rCost, pFrom->rCost); + rUnsorted = sqlite3LogEstAdd(pWLoop->rSetup,pWLoop->rRun + pFrom->nRow); + rUnsorted = sqlite3LogEstAdd(rUnsorted, pFrom->rUnsorted); nOut = pFrom->nRow + pWLoop->nOut; maskNew = pFrom->maskLoop | pWLoop->maskSelf; if( isOrdered<0 ){ isOrdered = wherePathSatisfiesOrderBy(pWInfo, pWInfo->pOrderBy, pFrom, pWInfo->wctrlFlags, iLoop, pWLoop, &revMask); - if( isOrdered>=0 && isOrdered<nOrderBy ){ - /* TUNING: Estimated cost of a full external sort, where N is - ** the number of rows to sort is: - ** - ** cost = (3.0 * N * log(N)). - ** - ** Or, if the order-by clause has X terms but only the last Y - ** terms are out of order, then block-sorting will reduce the - ** sorting cost to: - ** - ** cost = (3.0 * N * log(N)) * (Y/X) - ** - ** The (Y/X) term is implemented using stack variable rScale - ** below. */ - LogEst rScale, rSortCost; - assert( nOrderBy>0 && 66==sqlite3LogEst(100) ); - rScale = sqlite3LogEst((nOrderBy-isOrdered)*100/nOrderBy) - 66; - rSortCost = nRowEst + estLog(nRowEst) + rScale + 16; - - /* TUNING: The cost of implementing DISTINCT using a B-TREE is - ** similar but with a larger constant of proportionality. - ** Multiply by an additional factor of 3.0. */ - if( pWInfo->wctrlFlags & WHERE_WANT_DISTINCT ){ - rSortCost += 16; - } - WHERETRACE(0x002, - ("---- sort cost=%-3d (%d/%d) increases cost %3d to %-3d\n", - rSortCost, (nOrderBy-isOrdered), nOrderBy, rCost, - sqlite3LogEstAdd(rCost,rSortCost))); - rCost = sqlite3LogEstAdd(rCost, rSortCost); - } }else{ revMask = pFrom->revLoop; } - /* Check to see if pWLoop should be added to the mxChoice best so far */ + if( isOrdered>=0 && isOrdered<nOrderBy ){ + if( aSortCost[isOrdered]==0 ){ + aSortCost[isOrdered] = whereSortingCost( + pWInfo, nRowEst, nOrderBy, isOrdered + ); + } + rCost = sqlite3LogEstAdd(rUnsorted, aSortCost[isOrdered]); + + WHERETRACE(0x002, + ("---- sort cost=%-3d (%d/%d) increases cost %3d to %-3d\n", + aSortCost[isOrdered], (nOrderBy-isOrdered), nOrderBy, + rUnsorted, rCost)); + }else{ + rCost = rUnsorted; + } + + /* Check to see if pWLoop should be added to the set of + ** mxChoice best-so-far paths. + ** + ** First look for an existing path among best-so-far paths + ** that covers the same set of loops and has the same isOrdered + ** setting as the current path candidate. + ** + ** The term "((pTo->isOrdered^isOrdered)&0x80)==0" is equivalent + ** to (pTo->isOrdered==(-1))==(isOrdered==(-1))" for the range + ** of legal values for isOrdered, -1..64. + */ for(jj=0, pTo=aTo; jj<nTo; jj++, pTo++){ if( pTo->maskLoop==maskNew - && ((pTo->isOrdered^isOrdered)&80)==0 + && ((pTo->isOrdered^isOrdered)&0x80)==0 ){ testcase( jj==nTo-1 ); break; } } if( jj>=nTo ){ - if( nTo>=mxChoice && rCost>=mxCost ){ + /* None of the existing best-so-far paths match the candidate. */ + if( nTo>=mxChoice + && (rCost>mxCost || (rCost==mxCost && rUnsorted>=mxUnsorted)) + ){ + /* The current candidate is no better than any of the mxChoice + ** paths currently in the best-so-far buffer. So discard + ** this candidate as not viable. */ #ifdef WHERETRACE_ENABLED /* 0x4 */ if( sqlite3WhereTrace&0x4 ){ sqlite3DebugPrintf("Skip %s cost=%-3d,%3d order=%c\n", @@ -5414,7 +5778,8 @@ static int wherePathSolver(WhereInfo *pWInfo, LogEst nRowEst){ #endif continue; } - /* Add a new Path to the aTo[] set */ + /* If we reach this points it means that the new candidate path + ** needs to be added to the set of best-so-far paths. */ if( nTo<mxChoice ){ /* Increase the size of the aTo set by one */ jj = nTo++; @@ -5431,7 +5796,11 @@ static int wherePathSolver(WhereInfo *pWInfo, LogEst nRowEst){ } #endif }else{ - if( pTo->rCost<=rCost ){ + /* Control reaches here if best-so-far path pTo=aTo[jj] covers the + ** same set of loops and has the sam isOrdered setting as the + ** candidate path. Check to see if the candidate should replace + ** pTo or if the candidate should be skipped */ + if( pTo->rCost<rCost || (pTo->rCost==rCost && pTo->nRow<=nOut) ){ #ifdef WHERETRACE_ENABLED /* 0x4 */ if( sqlite3WhereTrace&0x4 ){ sqlite3DebugPrintf( @@ -5443,11 +5812,13 @@ static int wherePathSolver(WhereInfo *pWInfo, LogEst nRowEst){ pTo->isOrdered>=0 ? pTo->isOrdered+'0' : '?'); } #endif + /* Discard the candidate path from further consideration */ testcase( pTo->rCost==rCost ); continue; } testcase( pTo->rCost==rCost+1 ); - /* A new and better score for a previously created equivalent path */ + /* Control reaches here if the candidate path is better than the + ** pTo path. Replace pTo with the candidate. */ #ifdef WHERETRACE_ENABLED /* 0x4 */ if( sqlite3WhereTrace&0x4 ){ sqlite3DebugPrintf( @@ -5465,15 +5836,20 @@ static int wherePathSolver(WhereInfo *pWInfo, LogEst nRowEst){ pTo->revLoop = revMask; pTo->nRow = nOut; pTo->rCost = rCost; + pTo->rUnsorted = rUnsorted; pTo->isOrdered = isOrdered; memcpy(pTo->aLoop, pFrom->aLoop, sizeof(WhereLoop*)*iLoop); pTo->aLoop[iLoop] = pWLoop; if( nTo>=mxChoice ){ mxI = 0; mxCost = aTo[0].rCost; + mxUnsorted = aTo[0].nRow; for(jj=1, pTo=&aTo[1]; jj<mxChoice; jj++, pTo++){ - if( pTo->rCost>mxCost ){ + if( pTo->rCost>mxCost + || (pTo->rCost==mxCost && pTo->rUnsorted>mxUnsorted) + ){ mxCost = pTo->rCost; + mxUnsorted = pTo->rUnsorted; mxI = jj; } } @@ -5482,7 +5858,7 @@ static int wherePathSolver(WhereInfo *pWInfo, LogEst nRowEst){ } #ifdef WHERETRACE_ENABLED /* >=2 */ - if( sqlite3WhereTrace>=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", @@ -5548,12 +5924,15 @@ static int wherePathSolver(WhereInfo *pWInfo, LogEst nRowEst){ if( (pWInfo->wctrlFlags & WHERE_SORTBYGROUP) && pWInfo->nOBSat==pWInfo->pOrderBy->nExpr ){ - Bitmask notUsed = 0; + Bitmask revMask = 0; int nOrder = wherePathSatisfiesOrderBy(pWInfo, pWInfo->pOrderBy, - pFrom, 0, nLoop-1, pFrom->aLoop[nLoop-1], ¬Used + pFrom, 0, nLoop-1, pFrom->aLoop[nLoop-1], &revMask ); assert( pWInfo->sorted==0 ); - pWInfo->sorted = (nOrder==pWInfo->pOrderBy->nExpr); + if( nOrder==pWInfo->pOrderBy->nExpr ){ + pWInfo->sorted = 1; + pWInfo->revMask = revMask; + } } } @@ -5598,7 +5977,7 @@ static int whereShortCut(WhereLoopBuilder *pBuilder){ pWC = &pWInfo->sWC; pLoop = pBuilder->pNew; pLoop->wsFlags = 0; - pLoop->u.btree.nSkip = 0; + pLoop->nSkip = 0; pTerm = findTerm(pWC, iCur, -1, 0, WO_EQ, 0); if( pTerm ){ pLoop->wsFlags = WHERE_COLUMN_EQ|WHERE_IPK|WHERE_ONEROW; @@ -5610,8 +5989,7 @@ static int whereShortCut(WhereLoopBuilder *pBuilder){ }else{ for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){ assert( pLoop->aLTermSpace==pLoop->aLTerm ); - assert( ArraySize(pLoop->aLTermSpace)==4 ); - if( pIdx->onError==OE_None + if( !IsUniqueIndex(pIdx) || pIdx->pPartIdxWhere!=0 || pIdx->nKeyCol>ArraySize(pLoop->aLTermSpace) ) continue; @@ -5906,23 +6284,16 @@ WhereInfo *sqlite3WhereBegin( /* Construct the WhereLoop objects */ WHERETRACE(0xffff,("*** Optimizer Start ***\n")); +#if defined(WHERETRACE_ENABLED) /* Display all terms of the WHERE clause */ -#if defined(WHERETRACE_ENABLED) && defined(SQLITE_ENABLE_TREE_EXPLAIN) if( sqlite3WhereTrace & 0x100 ){ int i; - Vdbe *v = pParse->pVdbe; - sqlite3ExplainBegin(v); for(i=0; i<sWLB.pWC->nTerm; i++){ - sqlite3ExplainPrintf(v, "#%-2d ", i); - sqlite3ExplainPush(v); - whereExplainTerm(v, &sWLB.pWC->a[i]); - sqlite3ExplainPop(v); - sqlite3ExplainNL(v); + whereTermPrint(&sWLB.pWC->a[i], i); } - sqlite3ExplainFinish(v); - sqlite3DebugPrintf("%s", sqlite3VdbeExplanation(v)); } #endif + if( nTabList!=1 || whereShortCut(&sWLB)==0 ){ rc = whereLoopAddAll(&sWLB); if( rc ) goto whereBeginError; @@ -6101,6 +6472,7 @@ WhereInfo *sqlite3WhereBegin( pWInfo->aiCurOnePass[1] = iIndexCur; }else if( iIdxCur && (wctrlFlags & WHERE_ONETABLE_ONLY)!=0 ){ iIndexCur = iIdxCur; + if( wctrlFlags & WHERE_REOPEN_IDX ) op = OP_ReopenIdx; }else{ iIndexCur = pParse->nTab++; } @@ -6125,7 +6497,10 @@ WhereInfo *sqlite3WhereBegin( */ notReady = ~(Bitmask)0; for(ii=0; ii<nTabList; ii++){ + int addrExplain; + int wsFlags; pLevel = &pWInfo->a[ii]; + wsFlags = pLevel->pWLoop->wsFlags; #ifndef SQLITE_OMIT_AUTOMATIC_INDEX if( (pLevel->pWLoop->wsFlags & WHERE_AUTO_INDEX)!=0 ){ constructAutomaticIndex(pParse, &pWInfo->sWC, @@ -6133,10 +6508,15 @@ WhereInfo *sqlite3WhereBegin( if( db->mallocFailed ) goto whereBeginError; } #endif - explainOneScan(pParse, pTabList, pLevel, ii, pLevel->iFrom, wctrlFlags); + addrExplain = explainOneScan( + pParse, pTabList, pLevel, ii, pLevel->iFrom, wctrlFlags + ); pLevel->addrBody = sqlite3VdbeCurrentAddr(v); notReady = codeOneLoopStart(pWInfo, ii, notReady); pWInfo->iContinue = pLevel->addrCont; + if( (wsFlags&WHERE_MULTI_OR)==0 && (wctrlFlags&WHERE_ONETABLE_ONLY)==0 ){ + addScanStatus(v, pTabList, pLevel, addrExplain); + } } /* Done. */ |