diff options
Diffstat (limited to 'lib/libsqlite3/src/where.c')
| -rw-r--r-- | lib/libsqlite3/src/where.c | 1431 |
1 files changed, 1009 insertions, 422 deletions
diff --git a/lib/libsqlite3/src/where.c b/lib/libsqlite3/src/where.c index d8389a4d699..9c30136e876 100644 --- a/lib/libsqlite3/src/where.c +++ b/lib/libsqlite3/src/where.c @@ -39,7 +39,7 @@ int sqlite3WhereIsDistinct(WhereInfo *pWInfo){ ** Return FALSE if the output needs to be sorted. */ int sqlite3WhereIsOrdered(WhereInfo *pWInfo){ - return pWInfo->bOBSat!=0; + return pWInfo->nOBSat; } /* @@ -47,6 +47,7 @@ int sqlite3WhereIsOrdered(WhereInfo *pWInfo){ ** immediately with the next row of a WHERE clause. */ int sqlite3WhereContinueLabel(WhereInfo *pWInfo){ + assert( pWInfo->iContinue!=0 ); return pWInfo->iContinue; } @@ -226,7 +227,7 @@ static int whereClauseInsert(WhereClause *pWC, Expr *p, u8 wtFlags){ if( p && ExprHasProperty(p, EP_Unlikely) ){ pTerm->truthProb = sqlite3LogEst(p->iTable) - 99; }else{ - pTerm->truthProb = -1; + pTerm->truthProb = 1; } pTerm->pExpr = sqlite3ExprSkipCollate(p); pTerm->wtFlags = wtFlags; @@ -543,7 +544,7 @@ 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{ @@ -1469,7 +1470,7 @@ 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) ){ @@ -1493,8 +1494,7 @@ static int isDistinctRedundant( ** Estimate the logarithm of the input value to base 2. */ static LogEst estLog(LogEst N){ - LogEst x = sqlite3LogEst(N); - return x>33 ? x - 33 : 0; + return N<=10 ? 0 : sqlite3LogEst(N) - 33; } /* @@ -1955,10 +1955,11 @@ static void whereKeyStats( iLower = 0; iUpper = aSample[0].anLt[iCol]; }else{ - iUpper = i>=pIdx->nSample ? pIdx->aiRowEst[0] : aSample[i].anLt[iCol]; + i64 nRow0 = sqlite3LogEstToInt(pIdx->aiRowLogEst[0]); + 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{ @@ -1975,6 +1976,138 @@ static void whereKeyStats( #endif /* SQLITE_ENABLE_STAT3_OR_STAT4 */ /* +** If it is not NULL, pTerm is a term that provides an upper or lower +** bound on a range scan. Without considering pTerm, it is estimated +** that the scan will visit nNew rows. This function returns the number +** estimated to be visited after taking pTerm into account. +** +** If the user explicitly specified a likelihood() value for this term, +** then the return value is the likelihood multiplied by the number of +** input rows. Otherwise, this function assumes that an "IS NOT NULL" term +** has a likelihood of 0.50, and any other term a likelihood of 0.25. +*/ +static LogEst whereRangeAdjust(WhereTerm *pTerm, LogEst nNew){ + LogEst nRet = nNew; + if( pTerm ){ + if( pTerm->truthProb<=0 ){ + nRet += pTerm->truthProb; + }else if( (pTerm->wtFlags & TERM_VNULL)==0 ){ + nRet -= 20; assert( 20==sqlite3LogEst(4) ); + } + } + 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 ** bound, a lower bound, or both. The WHERE clause terms that set the upper @@ -2010,9 +2143,9 @@ static void whereKeyStats( ** to account for the range contraints pLower and pUpper. ** ** In the absence of sqlite_stat4 ANALYZE data, or if such data cannot be -** used, each range inequality reduces the search space by a factor of 4. -** Hence a pair of constraints (x>? AND x<?) reduces the expected number of -** rows visited by a factor of 16. +** used, a single range inequality reduces the search space by a factor of 4. +** and a pair of constraints (x>? AND x<?) reduces the expected number of +** rows visited by a factor of 64. */ static int whereRangeScanEst( Parse *pParse, /* Parsing & code generating context */ @@ -2030,95 +2163,100 @@ static int whereRangeScanEst( 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==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 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 = p->aiRowEst[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:$L). */ - if( pLower ){ - int bOk; /* True if value is extracted from pExpr */ - Expr *pExpr = pLower->pExpr->pRight; - assert( (pLower->eOperator & (WO_GT|WO_GE))!=0 ); - rc = sqlite3Stat4ProbeSetValue(pParse, p, &pRec, pExpr, aff, nEq, &bOk); - if( rc==SQLITE_OK && bOk ){ - tRowcnt iNew; + if( nEq==p->nKeyCol ){ + aff = SQLITE_AFF_INTEGER; + }else{ + aff = p->pTable->aCol[p->aiColumn[nEq]].affinity; + } + /* Determine iLower and iUpper using ($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 $P in whereEqualScanEst(). */ whereKeyStats(pParse, p, pRec, 0, a); - iNew = a[0] + ((pLower->eOperator & WO_GT) ? a[1] : 0); - if( iNew>iLower ) iLower = iNew; - nOut--; + iLower = a[0]; + iUpper = a[0] + a[1]; } - } - /* If possible, improve on the iUpper estimate using ($P:$U). */ - if( pUpper ){ - int bOk; /* True if value is extracted from pExpr */ - Expr *pExpr = pUpper->pExpr->pRight; - assert( (pUpper->eOperator & (WO_LT|WO_LE))!=0 ); - rc = sqlite3Stat4ProbeSetValue(pParse, p, &pRec, pExpr, aff, nEq, &bOk); - if( rc==SQLITE_OK && bOk ){ - tRowcnt iNew; - whereKeyStats(pParse, p, pRec, 1, a); - iNew = a[0] + ((pUpper->eOperator & WO_LE) ? a[1] : 0); - if( iNew<iUpper ) iUpper = iNew; - nOut--; + /* If possible, improve on the iLower estimate using ($P:$L). */ + if( pLower ){ + int bOk; /* True if value is extracted from pExpr */ + Expr *pExpr = pLower->pExpr->pRight; + assert( (pLower->eOperator & (WO_GT|WO_GE))!=0 ); + rc = sqlite3Stat4ProbeSetValue(pParse, p, &pRec, pExpr, aff, nEq, &bOk); + if( rc==SQLITE_OK && bOk ){ + tRowcnt iNew; + whereKeyStats(pParse, p, pRec, 0, a); + iNew = a[0] + ((pLower->eOperator & WO_GT) ? a[1] : 0); + if( iNew>iLower ) iLower = iNew; + nOut--; + } } - } - pBuilder->pRec = pRec; - if( rc==SQLITE_OK ){ - if( iUpper>iLower ){ - nNew = sqlite3LogEst(iUpper - iLower); - }else{ - nNew = 10; assert( 10==sqlite3LogEst(2) ); + /* If possible, improve on the iUpper estimate using ($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--; + } } - if( nNew<nOut ){ - nOut = nNew; + + pBuilder->pRec = pRec; + if( rc==SQLITE_OK ){ + if( iUpper>iLower ){ + nNew = sqlite3LogEst(iUpper - iLower); + }else{ + nNew = 10; assert( 10==sqlite3LogEst(2) ); + } + if( nNew<nOut ){ + nOut = nNew; + } + pLoop->nOut = (LogEst)nOut; + WHERETRACE(0x10, ("range scan regions: %u..%u est=%d\n", + (u32)iLower, (u32)iUpper, nOut)); + return SQLITE_OK; } - pLoop->nOut = (LogEst)nOut; - WHERETRACE(0x10, ("range scan regions: %u..%u est=%d\n", - (u32)iLower, (u32)iUpper, nOut)); - return SQLITE_OK; + }else{ + int bDone = 0; + rc = whereRangeSkipScanEst(pParse, pLower, pUpper, pLoop, &bDone); + if( bDone ) return rc; } } #else @@ -2126,17 +2264,18 @@ static int whereRangeScanEst( UNUSED_PARAMETER(pBuilder); #endif assert( pLower || pUpper ); - /* TUNING: Each inequality constraint reduces the search space 4-fold. - ** A BETWEEN operator, therefore, reduces the search space 16-fold */ - nNew = nOut; - if( pLower && (pLower->wtFlags & TERM_VNULL)==0 ){ - nNew -= 20; assert( 20==sqlite3LogEst(4) ); - nOut--; - } - if( pUpper ){ - nNew -= 20; assert( 20==sqlite3LogEst(4) ); - nOut--; - } + 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 + ** 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; + + nOut -= (pLower!=0) + (pUpper!=0); if( nNew<10 ) nNew = 10; if( nNew<nOut ) nOut = nNew; pLoop->nOut = (LogEst)nOut; @@ -2176,7 +2315,7 @@ 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 ); @@ -2189,7 +2328,7 @@ 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; } @@ -2233,6 +2372,7 @@ static int whereInScanEst( tRowcnt *pnRow /* Write the revised row estimate here */ ){ Index *p = pBuilder->pNew->u.btree.pIndex; + i64 nRow0 = sqlite3LogEstToInt(p->aiRowLogEst[0]); int nRecValid = pBuilder->nRecValid; int rc = SQLITE_OK; /* Subfunction return code */ tRowcnt nEst; /* Number of rows for a single term */ @@ -2241,14 +2381,14 @@ static int whereInScanEst( assert( p->aSample!=0 ); for(i=0; rc==SQLITE_OK && i<pList->nExpr; i++){ - nEst = p->aiRowEst[0]; + nEst = nRow0; rc = whereEqualScanEst(pParse, pBuilder, pList->a[i].pExpr, &nEst); nRowEst += nEst; pBuilder->nRecValid = nRecValid; } if( rc==SQLITE_OK ){ - if( nRowEst > p->aiRowEst[0] ) nRowEst = p->aiRowEst[0]; + if( nRowEst > nRow0 ) nRowEst = nRow0; *pnRow = nRowEst; WHERETRACE(0x10,("IN row estimate: est=%g\n", nRowEst)); } @@ -2382,7 +2522,7 @@ 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; @@ -2619,7 +2759,7 @@ static char *explainIndexRange(sqlite3 *db, WhereLoop *pLoop, Table *pTab){ txt.db = db; sqlite3StrAccumAppend(&txt, " (", 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, "="); }else{ @@ -2632,11 +2772,11 @@ static char *explainIndexRange(sqlite3 *db, WhereLoop *pLoop, Table *pTab){ j = i; if( pLoop->wsFlags&WHERE_BTM_LIMIT ){ - char *z = (j==pIndex->nKeyCol ) ? "rowid" : aCol[aiColumn[j]].zName; + char *z = aiColumn[j] < 0 ? "rowid" : aCol[aiColumn[j]].zName; explainAppendTerm(&txt, i++, z, ">"); } if( pLoop->wsFlags&WHERE_TOP_LIMIT ){ - char *z = (j==pIndex->nKeyCol ) ? "rowid" : aCol[aiColumn[j]].zName; + char *z = aiColumn[j] < 0 ? "rowid" : aCol[aiColumn[j]].zName; explainAppendTerm(&txt, i, z, "<"); } sqlite3StrAccumAppend(&txt, ")", 1); @@ -2691,13 +2831,20 @@ static void explainOneScan( 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); - zMsg = sqlite3MAppendf(db, zMsg, - ((flags & WHERE_AUTO_INDEX) ? - "%s USING AUTOMATIC %sINDEX%.0s%s" : - "%s USING %sINDEX %s%s"), - zMsg, ((flags & WHERE_IDX_ONLY) ? "COVERING " : ""), - pLoop->u.btree.pIndex->zName, zWhere); + 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"; + }else if( flags & WHERE_AUTO_INDEX ){ + zFmt = "%s USING AUTOMATIC COVERING INDEX%.0s%s"; + }else if( flags & WHERE_IDX_ONLY ){ + zFmt = "%s USING COVERING INDEX %s%s"; + }else{ + zFmt = "%s USING INDEX %s%s"; + } + 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); @@ -2840,7 +2987,7 @@ static Bitmask codeOneLoopStart( pLevel->p1 = iCur; pLevel->p2 = sqlite3VdbeCurrentAddr(v); sqlite3ReleaseTempRange(pParse, iReg, nConstraint+2); - sqlite3ExprCachePop(pParse, 1); + sqlite3ExprCachePop(pParse); }else #endif /* SQLITE_OMIT_VIRTUALTABLE */ @@ -3036,8 +3183,11 @@ static Bitmask codeOneLoopStart( ** the first one after the nEq equality constraints in the index, ** this requires some special handling. */ + assert( pWInfo->pOrderBy==0 + || pWInfo->pOrderBy->nExpr==1 + || (pWInfo->wctrlFlags&WHERE_ORDERBY_MIN)==0 ); if( (pWInfo->wctrlFlags&WHERE_ORDERBY_MIN)!=0 - && (pWInfo->bOBSat!=0) + && pWInfo->nOBSat>0 && (pIdx->nKeyCol>nEq) ){ assert( pLoop->u.btree.nSkip==0 ); @@ -3186,7 +3336,7 @@ static Bitmask codeOneLoopStart( sqlite3VdbeAddOp2(v, OP_IdxRowid, iIdxCur, iRowidReg); sqlite3ExprCacheStore(pParse, iCur, -1, iRowidReg); sqlite3VdbeAddOp2(v, OP_Seek, iCur, iRowidReg); /* Deferred seek */ - }else{ + }else if( iCur!=iIdxCur ){ Index *pPk = sqlite3PrimaryKeyIndex(pIdx->pTable); iRowidReg = sqlite3GetTempRange(pParse, pPk->nKeyCol); for(j=0; j<pPk->nKeyCol; j++){ @@ -3208,8 +3358,7 @@ static Bitmask codeOneLoopStart( pLevel->op = OP_Next; } pLevel->p1 = iIdxCur; - assert( (WHERE_UNQ_WANTED>>16)==1 ); - pLevel->p3 = (pLoop->wsFlags>>16)&1; + pLevel->p3 = (pLoop->wsFlags&WHERE_UNQ_WANTED)!=0 ? 1:0; if( (pLoop->wsFlags & WHERE_CONSTRAINT)==0 ){ pLevel->p5 = SQLITE_STMTSTATUS_FULLSCAN_STEP; }else{ @@ -3257,6 +3406,10 @@ 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 + ** keys of the rows we have already seen. + ** */ WhereClause *pOrWc; /* The OR-clause broken out into subterms */ SrcList *pOrTab; /* Shortened table list or OR-clause generation */ @@ -3270,7 +3423,9 @@ 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; pTerm = pLoop->aLTerm[0]; assert( pTerm!=0 ); @@ -3303,7 +3458,8 @@ static Bitmask codeOneLoopStart( } /* Initialize the rowset register to contain NULL. An SQL NULL is - ** equivalent to an empty rowset. + ** equivalent to an empty rowset. Or, create an ephermeral index + ** capable of holding primary keys in the case of a WITHOUT ROWID. ** ** Also initialize regReturn to contain the address of the instruction ** immediately following the OP_Return at the bottom of the loop. This @@ -3314,9 +3470,16 @@ static Bitmask codeOneLoopStart( ** called on an uninitialized cursor. */ if( (pWInfo->wctrlFlags & WHERE_DUPLICATES_OK)==0 ){ - regRowset = ++pParse->nMem; + if( HasRowid(pTab) ){ + regRowset = ++pParse->nMem; + sqlite3VdbeAddOp2(v, OP_Null, 0, regRowset); + }else{ + Index *pPk = sqlite3PrimaryKeyIndex(pTab); + regRowset = pParse->nTab++; + sqlite3VdbeAddOp2(v, OP_OpenEphemeral, regRowset, pPk->nKeyCol); + sqlite3VdbeSetP4KeyInfo(pParse, pPk); + } regRowid = ++pParse->nMem; - sqlite3VdbeAddOp2(v, OP_Null, 0, regRowset); } iRetInit = sqlite3VdbeAddOp2(v, OP_Integer, 0, regReturn); @@ -3352,36 +3515,88 @@ static Bitmask codeOneLoopStart( } } + /* Run a separate WHERE clause for each term of the OR clause. After + ** 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_AND_ONLY | + 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 ){ - WhereInfo *pSubWInfo; /* Info for single OR-term scan */ - Expr *pOrExpr = pOrTerm->pExpr; + WhereInfo *pSubWInfo; /* Info for single OR-term scan */ + Expr *pOrExpr = pOrTerm->pExpr; /* Current OR clause term */ + int j1 = 0; /* Address of jump operation */ if( pAndExpr && !ExprHasProperty(pOrExpr, EP_FromJoin) ){ pAndExpr->pLeft = pOrExpr; pOrExpr = pAndExpr; } /* Loop through table entries that match term pOrTerm. */ 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( pParse, pOrTab, &pSubWInfo->a[0], iLevel, pLevel->iFrom, 0 ); + /* 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 + ** row will be skipped in subsequent sub-WHERE clauses. + */ if( (pWInfo->wctrlFlags & WHERE_DUPLICATES_OK)==0 ){ - int iSet = ((ii==pOrWc->nTerm-1)?-1:ii); int r; - r = sqlite3ExprCodeGetColumn(pParse, pTabItem->pTab, -1, iCur, - regRowid, 0); - sqlite3VdbeAddOp4Int(v, OP_RowSetTest, regRowset, - sqlite3VdbeCurrentAddr(v)+2, r, iSet); - VdbeCoverage(v); + int iSet = ((ii==pOrWc->nTerm-1)?-1:ii); + if( HasRowid(pTab) ){ + r = sqlite3ExprCodeGetColumn(pParse, pTab, -1, iCur, regRowid, 0); + j1 = sqlite3VdbeAddOp4Int(v, OP_RowSetTest, regRowset, 0, r,iSet); + VdbeCoverage(v); + }else{ + Index *pPk = sqlite3PrimaryKeyIndex(pTab); + int nPk = pPk->nKeyCol; + int iPk; + + /* Read the PK into an array of temp registers. */ + r = sqlite3GetTempRange(pParse, nPk); + for(iPk=0; iPk<nPk; iPk++){ + int iCol = pPk->aiColumn[iPk]; + sqlite3ExprCodeGetColumn(pParse, pTab, iCol, iCur, r+iPk, 0); + } + + /* Check if the temp table already contains this key. If so, + ** the row has already been included in the result set and + ** can be ignored (by jumping past the Gosub below). Otherwise, + ** insert the key into the temp table and proceed with processing + ** the row. + ** + ** Use some of the same optimizations as OP_RowSetTest: If iSet + ** is zero, assume that the key cannot already be present in + ** the temp table. And if iSet is -1, assume that there is no + ** need to insert the key into the temp table, as it will never + ** be tested for. */ + if( iSet ){ + j1 = sqlite3VdbeAddOp4Int(v, OP_Found, regRowset, 0, r, nPk); + VdbeCoverage(v); + } + if( iSet>=0 ){ + sqlite3VdbeAddOp3(v, OP_MakeRecord, r, nPk, regRowid); + sqlite3VdbeAddOp3(v, OP_IdxInsert, regRowset, regRowid, 0); + if( iSet ) sqlite3VdbeChangeP5(v, OPFLAG_USESEEKRESULT); + } + + /* Release the array of temp registers */ + sqlite3ReleaseTempRange(pParse, r, nPk); + } } + + /* Invoke the main loop body as a subroutine */ sqlite3VdbeAddOp2(v, OP_Gosub, regReturn, iLoopBody); + /* Jump here (skipping the main loop body subroutine) if the + ** current sub-WHERE row is a duplicate from prior sub-WHEREs. */ + if( j1 ) sqlite3VdbeJumpHere(v, j1); + /* The pSubWInfo->untestedTerms flag means that this OR term ** contained one or more AND term from a notReady table. The ** terms from the notReady table could not be tested and will @@ -3405,9 +3620,11 @@ static Bitmask codeOneLoopStart( assert( (pSubLoop->wsFlags & WHERE_AUTO_INDEX)==0 ); if( (pSubLoop->wsFlags & WHERE_INDEXED)!=0 && (ii==0 || pSubLoop->u.btree.pIndex==pCov) + && (HasRowid(pTab) || !IsPrimaryKeyIndex(pSubLoop->u.btree.pIndex)) ){ assert( pSubWInfo->a[0].iIdxCur==iCovCur ); pCov = pSubLoop->u.btree.pIndex; + wctrlFlags |= WHERE_REOPEN_IDX; }else{ pCov = 0; } @@ -3586,7 +3803,7 @@ static void whereLoopPrint(WhereLoop *p, WhereClause *pWC){ sqlite3DebugPrintf(" %-19s", z); sqlite3_free(z); } - sqlite3DebugPrintf(" f %04x N %d", p->wsFlags, p->nLTerm); + 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 @@ -3709,6 +3926,161 @@ static void whereInfoFree(sqlite3 *db, WhereInfo *pWInfo){ } /* +** Return TRUE if both of the following are true: +** +** (1) X has the same or lower cost that Y +** (2) X is a proper subset of 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 +** by Y. +** +** 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. +*/ +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->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--){ + for(j=pY->nLTerm-1; j>=0; j--){ + if( pY->aLTerm[j]==pX->aLTerm[i] ) break; + } + if( j<0 ) return 0; /* X not a subset of Y since term X[i] not used by Y */ + } + return 1; /* All conditions meet */ +} + +/* +** Try to adjust the cost of WhereLoop pTemplate upwards or downwards so +** that: +** +** (1) pTemplate costs less than any other WhereLoops that are a proper +** subset of pTemplate +** +** (2) pTemplate costs more than any other WhereLoops for which pTemplate +** is a proper subset. +** +** 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 */ + 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; + } + } +} + +/* +** Search the list of WhereLoops in *ppPrev looking for one that can be +** supplanted by pTemplate. +** +** Return NULL if the WhereLoop list contains an entry that can supplant +** pTemplate, in other words if pTemplate does not belong on the list. +** +** If pX is a WhereLoop that pTemplate can supplant, then return the +** link that points to pX. +** +** If pTemplate cannot supplant any existing element of the list but needs +** to be added to the list, then return a pointer to the tail of the list. +*/ +static WhereLoop **whereLoopFindLesser( + WhereLoop **ppPrev, + const WhereLoop *pTemplate +){ + WhereLoop *p; + for(p=(*ppPrev); p; ppPrev=&p->pNextLoop, p=*ppPrev){ + if( p->iTab!=pTemplate->iTab || p->iSortIdx!=pTemplate->iSortIdx ){ + /* If either the iTab or iSortIdx values for two WhereLoop are different + ** then those WhereLoops need to be considered separately. Neither is + ** a candidate to replace the other. */ + continue; + } + /* In the current implementation, the rSetup value is either zero + ** or the cost of building an automatic index (NlogN) and the NlogN + ** is the same for compatible WhereLoops. */ + assert( p->rSetup==0 || pTemplate->rSetup==0 + || p->rSetup==pTemplate->rSetup ); + + /* whereLoopAddBtree() always generates and inserts the automatic index + ** case first. Hence compatible candidate WhereLoops never have a larger + ** rSetup. Call this SETUP-INVARIANT */ + assert( p->rSetup>=pTemplate->rSetup ); + + /* Any loop using an appliation-defined index (or PRIMARY KEY or + ** UNIQUE constraint) with one or more == constraints is better + ** than an automatic index. */ + if( (p->wsFlags & WHERE_AUTO_INDEX)!=0 + && (pTemplate->wsFlags & WHERE_INDEXED)!=0 + && (pTemplate->wsFlags & WHERE_COLUMN_EQ)!=0 + && (p->prereq & pTemplate->prereq)==pTemplate->prereq + ){ + break; + } + + /* If existing WhereLoop p is better than pTemplate, pTemplate can be + ** discarded. WhereLoop p is better if: + ** (1) p has no more dependencies than pTemplate, and + ** (2) p has an equal or lower cost than pTemplate + */ + if( (p->prereq & pTemplate->prereq)==p->prereq /* (1) */ + && p->rSetup<=pTemplate->rSetup /* (2a) */ + && p->rRun<=pTemplate->rRun /* (2b) */ + && p->nOut<=pTemplate->nOut /* (2c) */ + ){ + return 0; /* Discard pTemplate */ + } + + /* If pTemplate is always better than p, then cause p to be overwritten + ** with pTemplate. pTemplate is better than p if: + ** (1) pTemplate has no more dependences than p, and + ** (2) pTemplate has an equal or lower cost than p. + */ + if( (p->prereq & pTemplate->prereq)==pTemplate->prereq /* (1) */ + && p->rRun>=pTemplate->rRun /* (2a) */ + && p->nOut>=pTemplate->nOut /* (2b) */ + ){ + assert( p->rSetup>=pTemplate->rSetup ); /* SETUP-INVARIANT above */ + break; /* Cause p to be overwritten by pTemplate */ + } + } + return ppPrev; +} + +/* ** Insert or replace a WhereLoop entry using the template supplied. ** ** An existing WhereLoop entry might be overwritten if the new template @@ -3717,25 +4089,23 @@ static void whereInfoFree(sqlite3 *db, WhereInfo *pWInfo){ ** fewer dependencies than the template. Otherwise a new WhereLoop is ** added based on the template. ** -** If pBuilder->pOrSet is not NULL then we only care about only the +** If pBuilder->pOrSet is not NULL then we care about only the ** prerequisites and rRun and nOut costs of the N best loops. That ** information is gathered in the pBuilder->pOrSet object. This special ** processing mode is used only for OR clause processing. ** ** When accumulating multiple loops (when pBuilder->pOrSet is NULL) we ** still might overwrite similar loops with the new template if the -** template is better. Loops may be overwritten if the following +** new template is better. Loops may be overwritten if the following ** conditions are met: ** ** (1) They have the same iTab. ** (2) They have the same iSortIdx. ** (3) The template has same or fewer dependencies than the current loop ** (4) The template has the same or lower cost than the current loop -** (5) The template uses more terms of the same index but has no additional -** dependencies */ static int whereLoopInsert(WhereLoopBuilder *pBuilder, WhereLoop *pTemplate){ - WhereLoop **ppPrev, *p, *pNext = 0; + WhereLoop **ppPrev, *p; WhereInfo *pWInfo = pBuilder->pWInfo; sqlite3 *db = pWInfo->pParse->db; @@ -3758,64 +4128,23 @@ static int whereLoopInsert(WhereLoopBuilder *pBuilder, WhereLoop *pTemplate){ return SQLITE_OK; } - /* Search for an existing WhereLoop to overwrite, or which takes - ** priority over pTemplate. + /* Look for an existing WhereLoop to replace with pTemplate */ - for(ppPrev=&pWInfo->pLoops, p=*ppPrev; p; ppPrev=&p->pNextLoop, p=*ppPrev){ - if( p->iTab!=pTemplate->iTab || p->iSortIdx!=pTemplate->iSortIdx ){ - /* If either the iTab or iSortIdx values for two WhereLoop are different - ** then those WhereLoops need to be considered separately. Neither is - ** a candidate to replace the other. */ - continue; - } - /* In the current implementation, the rSetup value is either zero - ** or the cost of building an automatic index (NlogN) and the NlogN - ** is the same for compatible WhereLoops. */ - assert( p->rSetup==0 || pTemplate->rSetup==0 - || p->rSetup==pTemplate->rSetup ); - - /* whereLoopAddBtree() always generates and inserts the automatic index - ** case first. Hence compatible candidate WhereLoops never have a larger - ** rSetup. Call this SETUP-INVARIANT */ - assert( p->rSetup>=pTemplate->rSetup ); + whereLoopAdjustCost(pWInfo->pLoops, pTemplate); + ppPrev = whereLoopFindLesser(&pWInfo->pLoops, pTemplate); - if( (p->prereq & pTemplate->prereq)==p->prereq - && p->rSetup<=pTemplate->rSetup - && p->rRun<=pTemplate->rRun - && p->nOut<=pTemplate->nOut - ){ - /* This branch taken when p is equal or better than pTemplate in - ** all of (1) dependencies (2) setup-cost, (3) run-cost, and - ** (4) number of output rows. */ - assert( p->rSetup==pTemplate->rSetup ); - if( p->prereq==pTemplate->prereq - && p->nLTerm<pTemplate->nLTerm - && (p->wsFlags & pTemplate->wsFlags & WHERE_INDEXED)!=0 - && (p->u.btree.pIndex==pTemplate->u.btree.pIndex - || pTemplate->rRun+p->nLTerm<=p->rRun+pTemplate->nLTerm) - ){ - /* Overwrite an existing WhereLoop with an similar one that uses - ** more terms of the index */ - pNext = p->pNextLoop; - break; - }else{ - /* pTemplate is not helpful. - ** Return without changing or adding anything */ - goto whereLoopInsert_noop; - } - } - if( (p->prereq & pTemplate->prereq)==pTemplate->prereq - && p->rRun>=pTemplate->rRun - && p->nOut>=pTemplate->nOut - ){ - /* Overwrite an existing WhereLoop with a better one: one that is - ** better at one of (1) dependencies, (2) setup-cost, (3) run-cost - ** or (4) number of output rows, and is no worse in any of those - ** categories. */ - assert( p->rSetup>=pTemplate->rSetup ); /* SETUP-INVARIANT above */ - pNext = p->pNextLoop; - break; + if( ppPrev==0 ){ + /* There already exists a WhereLoop on the list that is better + ** than pTemplate, so just ignore pTemplate */ +#if WHERETRACE_ENABLED /* 0x8 */ + if( sqlite3WhereTrace & 0x8 ){ + sqlite3DebugPrintf("ins-noop: "); + whereLoopPrint(pTemplate, pBuilder->pWC); } +#endif + return SQLITE_OK; + }else{ + p = *ppPrev; } /* If we reach this point it means that either p[] should be overwritten @@ -3833,13 +4162,33 @@ static int whereLoopInsert(WhereLoopBuilder *pBuilder, WhereLoop *pTemplate){ } #endif if( p==0 ){ - p = sqlite3DbMallocRaw(db, sizeof(WhereLoop)); + /* Allocate a new WhereLoop to add to the end of the list */ + *ppPrev = p = sqlite3DbMallocRaw(db, sizeof(WhereLoop)); if( p==0 ) return SQLITE_NOMEM; whereLoopInit(p); + p->pNextLoop = 0; + }else{ + /* We will be overwriting WhereLoop p[]. But before we do, first + ** go through the rest of the list and delete any other entries besides + ** p[] that are also supplated by pTemplate */ + WhereLoop **ppTail = &p->pNextLoop; + WhereLoop *pToDel; + while( *ppTail ){ + ppTail = whereLoopFindLesser(ppTail, pTemplate); + if( ppTail==0 ) break; + pToDel = *ppTail; + if( pToDel==0 ) break; + *ppTail = pToDel->pNextLoop; +#if WHERETRACE_ENABLED /* 0x8 */ + if( sqlite3WhereTrace & 0x8 ){ + sqlite3DebugPrintf("ins-del: "); + whereLoopPrint(pToDel, pBuilder->pWC); + } +#endif + whereLoopDelete(db, pToDel); + } } whereLoopXfer(db, p, pTemplate); - p->pNextLoop = pNext; - *ppPrev = p; if( (p->wsFlags & WHERE_VIRTUALTABLE)==0 ){ Index *pIndex = p->u.btree.pIndex; if( pIndex && pIndex->tnum==0 ){ @@ -3847,16 +4196,6 @@ static int whereLoopInsert(WhereLoopBuilder *pBuilder, WhereLoop *pTemplate){ } } return SQLITE_OK; - - /* Jump here if the insert is a no-op */ -whereLoopInsert_noop: -#if WHERETRACE_ENABLED /* 0x8 */ - if( sqlite3WhereTrace & 0x8 ){ - sqlite3DebugPrintf("ins-noop: "); - whereLoopPrint(pTemplate, pBuilder->pWC); - } -#endif - return SQLITE_OK; } /* @@ -3886,13 +4225,30 @@ static void whereLoopOutputAdjust(WhereClause *pWC, WhereLoop *pLoop){ if( pX==pTerm ) break; if( pX->iParent>=0 && (&pWC->a[pX->iParent])==pTerm ) break; } - if( j<0 ) pLoop->nOut += pTerm->truthProb; + if( j<0 ){ + pLoop->nOut += (pTerm->truthProb<=0 ? pTerm->truthProb : -1); + } } } /* -** We have so far matched pBuilder->pNew->u.btree.nEq terms of the index pIndex. -** Try to match one more. +** 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. +** +** When this function is called, pBuilder->pNew->nOut contains the +** number of rows expected to be visited by filtering using the nEq +** terms only. If it is modified, this value is restored before this +** function returns. ** ** If pProbe->tnum==0, that means pIndex is a fake index used for the ** INTEGER PRIMARY KEY. @@ -3918,7 +4274,6 @@ static int whereLoopAddBtreeIndex( LogEst saved_nOut; /* Original value of pNew->nOut */ int iCol; /* Index of the column in the table */ int rc = SQLITE_OK; /* Return code */ - LogEst nRowEst; /* Estimated index selectivity */ LogEst rLogSize; /* Logarithm of table size */ WhereTerm *pTop = 0, *pBtm = 0; /* Top and bottom range constraints */ @@ -3936,15 +4291,9 @@ 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]; - nRowEst = sqlite3LogEst(pProbe->aiRowEst[pNew->u.btree.nEq+1]); - if( nRowEst==0 && pProbe->onError==OE_None ) nRowEst = 1; - }else{ - iCol = -1; - nRowEst = 0; - } + 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; @@ -3954,18 +4303,23 @@ static int whereLoopAddBtreeIndex( saved_prereq = pNew->prereq; saved_nOut = pNew->nOut; pNew->rSetup = 0; - rLogSize = estLog(sqlite3LogEst(pProbe->aiRowEst[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 was found by experimentation to be the payoff point where - ** skip-scan become faster than a full-scan. - */ + ** 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->aiRowEst[saved_nEq+1]>=18 /* TUNING: Minimum for skip-scan */ + && pProbe->aiRowLogEst[saved_nEq+1]>=42 /* TUNING: Minimum for skip-scan */ && (rc = whereLoopResize(db, pNew, pNew->nLTerm+1))==SQLITE_OK ){ LogEst nIter; @@ -3973,34 +4327,40 @@ static int whereLoopAddBtreeIndex( pNew->u.btree.nSkip++; pNew->aLTerm[pNew->nLTerm++] = 0; pNew->wsFlags |= WHERE_SKIPSCAN; - nIter = sqlite3LogEst(pProbe->aiRowEst[0]/pProbe->aiRowEst[saved_nEq+1]); - pNew->rRun = rLogSize + nIter; - pNew->nOut += nIter; - whereLoopAddBtreeIndex(pBuilder, pSrc, pProbe, nIter); + nIter = pProbe->aiRowLogEst[saved_nEq] - pProbe->aiRowLogEst[saved_nEq+1]; + pNew->nOut -= nIter; + whereLoopAddBtreeIndex(pBuilder, pSrc, pProbe, nIter + nInMul); pNew->nOut = saved_nOut; } for(; rc==SQLITE_OK && pTerm!=0; pTerm = whereScanNext(&scan)){ + u16 eOp = pTerm->eOperator; /* Shorthand for pTerm->eOperator */ + LogEst rCostIdx; + LogEst nOutUnadjusted; /* nOut before IN() and WHERE adjustments */ int nIn = 0; #ifdef SQLITE_ENABLE_STAT3_OR_STAT4 int nRecValid = pBuilder->nRecValid; #endif - if( (pTerm->eOperator==WO_ISNULL || (pTerm->wtFlags&TERM_VNULL)!=0) + if( (eOp==WO_ISNULL || (pTerm->wtFlags&TERM_VNULL)!=0) && (iCol<0 || pSrc->pTab->aCol[iCol].notNull) ){ continue; /* ignore IS [NOT] NULL constraints on NOT NULL columns */ } if( pTerm->prereqRight & pNew->maskSelf ) continue; - assert( pNew->nOut==saved_nOut ); - pNew->wsFlags = saved_wsFlags; pNew->u.btree.nEq = saved_nEq; pNew->nLTerm = saved_nLTerm; if( whereLoopResize(db, pNew, pNew->nLTerm+1) ) break; /* OOM */ pNew->aLTerm[pNew->nLTerm++] = pTerm; pNew->prereq = (saved_prereq | pTerm->prereqRight) & ~pNew->maskSelf; - pNew->rRun = rLogSize; /* Baseline cost is log2(N). Adjustments below */ - if( pTerm->eOperator & WO_IN ){ + + assert( nInMul==0 + || (pNew->wsFlags & WHERE_COLUMN_NULL)!=0 + || (pNew->wsFlags & WHERE_COLUMN_IN)!=0 + || (pNew->wsFlags & WHERE_SKIPSCAN)!=0 + ); + + if( eOp & WO_IN ){ Expr *pExpr = pTerm->pExpr; pNew->wsFlags |= WHERE_COLUMN_IN; if( ExprHasProperty(pExpr, EP_xIsSelect) ){ @@ -4010,85 +4370,120 @@ static int whereLoopAddBtreeIndex( /* "x IN (value, value, ...)" */ nIn = sqlite3LogEst(pExpr->x.pList->nExpr); } - pNew->rRun += nIn; - pNew->u.btree.nEq++; - pNew->nOut = nRowEst + nInMul + nIn; - }else if( pTerm->eOperator & (WO_EQ) ){ - assert( - (pNew->wsFlags & (WHERE_COLUMN_NULL|WHERE_COLUMN_IN|WHERE_SKIPSCAN))!=0 - || nInMul==0 - ); + assert( nIn>0 ); /* RHS always has 2 or more terms... The parser + ** changes "x IN (?)" into "x=?". */ + + }else if( eOp & (WO_EQ) ){ pNew->wsFlags |= WHERE_COLUMN_EQ; - if( iCol<0 || (nInMul==0 && pNew->u.btree.nEq==pProbe->nKeyCol-1)){ - assert( (pNew->wsFlags & WHERE_COLUMN_IN)==0 || iCol<0 ); - if( iCol>=0 && pProbe->onError==OE_None ){ + if( iCol<0 || (nInMul==0 && pNew->u.btree.nEq==pProbe->nKeyCol-1) ){ + if( iCol>=0 && !IsUniqueIndex(pProbe) ){ pNew->wsFlags |= WHERE_UNQ_WANTED; }else{ pNew->wsFlags |= WHERE_ONEROW; } } - pNew->u.btree.nEq++; - pNew->nOut = nRowEst + nInMul; - }else if( pTerm->eOperator & (WO_ISNULL) ){ + }else if( eOp & WO_ISNULL ){ pNew->wsFlags |= WHERE_COLUMN_NULL; - pNew->u.btree.nEq++; - /* TUNING: IS NULL selects 2 rows */ - nIn = 10; assert( 10==sqlite3LogEst(2) ); - pNew->nOut = nRowEst + nInMul + nIn; - }else if( pTerm->eOperator & (WO_GT|WO_GE) ){ - testcase( pTerm->eOperator & WO_GT ); - testcase( pTerm->eOperator & WO_GE ); + }else if( eOp & (WO_GT|WO_GE) ){ + testcase( eOp & WO_GT ); + testcase( eOp & WO_GE ); pNew->wsFlags |= WHERE_COLUMN_RANGE|WHERE_BTM_LIMIT; pBtm = pTerm; pTop = 0; }else{ - assert( pTerm->eOperator & (WO_LT|WO_LE) ); - testcase( pTerm->eOperator & WO_LT ); - testcase( pTerm->eOperator & WO_LE ); + assert( eOp & (WO_LT|WO_LE) ); + testcase( eOp & WO_LT ); + testcase( eOp & WO_LE ); pNew->wsFlags |= WHERE_COLUMN_RANGE|WHERE_TOP_LIMIT; pTop = pTerm; pBtm = (pNew->wsFlags & WHERE_BTM_LIMIT)!=0 ? pNew->aLTerm[pNew->nLTerm-2] : 0; } + + /* At this point pNew->nOut is set to the number of rows expected to + ** be visited by the index scan before considering term pTerm, or the + ** values of nIn and nInMul. In other words, assuming that all + ** "x IN(...)" terms are replaced with "x = ?". This block updates + ** the value of pNew->nOut to account for pTerm (but not nIn/nInMul). */ + assert( pNew->nOut==saved_nOut ); if( pNew->wsFlags & WHERE_COLUMN_RANGE ){ - /* Adjust nOut and rRun for STAT3 range values */ - assert( pNew->nOut==saved_nOut ); + /* Adjust nOut using stat3/stat4 data. Or, if there is no stat3/stat4 + ** data, using some other estimate. */ whereRangeScanEst(pParse, pBuilder, pBtm, pTop, pNew); - } + }else{ + int nEq = ++pNew->u.btree.nEq; + assert( eOp & (WO_ISNULL|WO_EQ|WO_IN) ); + + assert( pNew->nOut==saved_nOut ); + if( pTerm->truthProb<=0 && iCol>=0 ){ + assert( (eOp & WO_IN) || nIn==0 ); + testcase( eOp & WO_IN ); + pNew->nOut += pTerm->truthProb; + pNew->nOut -= nIn; + }else{ #ifdef SQLITE_ENABLE_STAT3_OR_STAT4 - if( nInMul==0 - && pProbe->nSample - && pNew->u.btree.nEq<=pProbe->nSampleCol - && OptimizationEnabled(db, SQLITE_Stat3) - ){ - Expr *pExpr = pTerm->pExpr; - tRowcnt nOut = 0; - if( (pTerm->eOperator & (WO_EQ|WO_ISNULL))!=0 ){ - testcase( pTerm->eOperator & WO_EQ ); - testcase( pTerm->eOperator & WO_ISNULL ); - rc = whereEqualScanEst(pParse, pBuilder, pExpr->pRight, &nOut); - }else if( (pTerm->eOperator & WO_IN) - && !ExprHasProperty(pExpr, EP_xIsSelect) ){ - rc = whereInScanEst(pParse, pBuilder, pExpr->x.pList, &nOut); - } - assert( nOut==0 || rc==SQLITE_OK ); - if( nOut ){ - pNew->nOut = sqlite3LogEst(nOut); - if( pNew->nOut>saved_nOut ) pNew->nOut = saved_nOut; + tRowcnt nOut = 0; + 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; + if( (eOp & (WO_EQ|WO_ISNULL))!=0 ){ + testcase( eOp & WO_EQ ); + testcase( eOp & WO_ISNULL ); + rc = whereEqualScanEst(pParse, pBuilder, pExpr->pRight, &nOut); + }else{ + rc = whereInScanEst(pParse, pBuilder, pExpr->x.pList, &nOut); + } + if( rc==SQLITE_NOTFOUND ) rc = SQLITE_OK; + if( rc!=SQLITE_OK ) break; /* Jump out of the pTerm loop */ + if( nOut ){ + pNew->nOut = sqlite3LogEst(nOut); + if( pNew->nOut>saved_nOut ) pNew->nOut = saved_nOut; + pNew->nOut -= nIn; + } + } + if( nOut==0 ) +#endif + { + pNew->nOut += (pProbe->aiRowLogEst[nEq] - pProbe->aiRowLogEst[nEq-1]); + if( eOp & WO_ISNULL ){ + /* TUNING: If there is no likelihood() value, assume that a + ** "col IS NULL" expression matches twice as many rows + ** as (col=?). */ + pNew->nOut += 10; + } + } } } -#endif + + /* Set rCostIdx to the cost of visiting selected rows in index. Add + ** it to pNew->rRun, which is currently set to the cost of the index + ** seek only. Then, if this is a non-covering index, add the cost of + ** visiting the rows in the main table. */ + rCostIdx = pNew->nOut + 1 + (15*pProbe->szIdxRow)/pSrc->pTab->szTabRow; + pNew->rRun = sqlite3LogEstAdd(rLogSize, rCostIdx); 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 = sqlite3LogEstAdd(pNew->rRun,rLogSize>27 ? rLogSize-17 : 10); + pNew->rRun = sqlite3LogEstAdd(pNew->rRun, pNew->nOut + 16); } - /* Step cost for each output row */ - pNew->rRun = sqlite3LogEstAdd(pNew->rRun, pNew->nOut); + ApplyCostMultiplier(pNew->rRun, pProbe->pTable->costMult); + + nOutUnadjusted = pNew->nOut; + pNew->rRun += nInMul + nIn; + pNew->nOut += nInMul + nIn; whereLoopOutputAdjust(pBuilder->pWC, pNew); rc = whereLoopInsert(pBuilder, pNew); + + if( pNew->wsFlags & WHERE_COLUMN_RANGE ){ + pNew->nOut = saved_nOut; + }else{ + pNew->nOut = nOutUnadjusted; + } + 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); } @@ -4170,6 +4565,37 @@ static int whereUsablePartialIndex(int iTab, WhereClause *pWC, Expr *pWhere){ ** Add all WhereLoop objects for a single table of the join where the table ** is idenfied by pBuilder->pNew->iTab. That table is guaranteed to be ** a b-tree table, not a virtual table. +** +** The costs (WhereLoop.rRun) of the b-tree loops added by this function +** are calculated as follows: +** +** For a full scan, assuming the table (or index) contains nRow rows: +** +** cost = nRow * 3.0 // full-table scan +** cost = nRow * K // scan of covering index +** cost = nRow * (K+3.0) // scan of non-covering index +** +** where K is a value between 1.1 and 3.0 set based on the relative +** estimated average size of the index and table records. +** +** For an index scan, where nVisit is the number of index rows visited +** by the scan, and nSeek is the number of seek operations required on +** the index b-tree: +** +** cost = nSeek * (log(nRow) + K * nVisit) // covering index +** cost = nSeek * (log(nRow) + (K+3.0) * nVisit) // non-covering index +** +** 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 */ @@ -4178,7 +4604,7 @@ static int whereLoopAddBtree( WhereInfo *pWInfo; /* WHERE analysis context */ Index *pProbe; /* An index we are evaluating */ Index sPk; /* A fake index object for the primary key */ - tRowcnt aiRowEstPk[2]; /* The aiRowEst[] value for the sPk index */ + LogEst aiRowEstPk[2]; /* The aiRowLogEst[] value for the sPk index */ i16 aiColumnPk = -1; /* The aColumn[] value for the sPk index */ SrcList *pTabList; /* The FROM clause */ struct SrcList_item *pSrc; /* The FROM clause btree term to add */ @@ -4212,12 +4638,14 @@ 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.aiRowEst = aiRowEstPk; + sPk.aiRowLogEst = aiRowEstPk; sPk.onError = OE_Replace; sPk.pTable = pTab; - aiRowEstPk[0] = pTab->nRowEst; - aiRowEstPk[1] = 1; + sPk.szIdxRow = pTab->szTabRow; + aiRowEstPk[0] = pTab->nRowLogEst; + aiRowEstPk[1] = 0; pFirst = pSrc->pTab->pIndex; if( pSrc->notIndexed==0 ){ /* The real indices of the table are only considered if the @@ -4226,7 +4654,7 @@ static int whereLoopAddBtree( } pProbe = &sPk; } - rSize = sqlite3LogEst(pTab->nRowEst); + rSize = pTab->nRowLogEst; rLogSize = estLog(rSize); #ifndef SQLITE_OMIT_AUTOMATIC_INDEX @@ -4255,6 +4683,7 @@ static int whereLoopAddBtree( ** 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) ); + 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 @@ -4276,6 +4705,7 @@ static int whereLoopAddBtree( && !whereUsablePartialIndex(pNew->iTab, pWC, pProbe->pPartIdxWhere) ){ continue; /* Partial index inappropriate for this query */ } + rSize = pProbe->aiRowLogEst[0]; pNew->u.btree.nEq = 0; pNew->u.btree.nSkip = 0; pNew->nLTerm = 0; @@ -4293,10 +4723,9 @@ static int whereLoopAddBtree( /* Full table scan */ pNew->iSortIdx = b ? iSortIdx : 0; - /* TUNING: Cost of full table scan is 3*(N + log2(N)). - ** + The extra 3 factor is to encourage the use of indexed lookups - ** over full scans. FIXME */ - pNew->rRun = sqlite3LogEstAdd(rSize,rLogSize) + 16; + /* TUNING: Cost of full table scan is (N*3.0). */ + pNew->rRun = rSize + 16; + ApplyCostMultiplier(pNew->rRun, pTab->costMult); whereLoopOutputAdjust(pWC, pNew); rc = whereLoopInsert(pBuilder, pNew); pNew->nOut = rSize; @@ -4323,19 +4752,16 @@ static int whereLoopAddBtree( ) ){ pNew->iSortIdx = b ? iSortIdx : 0; - if( m==0 ){ - /* TUNING: Cost of a covering index scan is K*(N + log2(N)). - ** + The extra factor K of between 1.1 and 3.0 that depends - ** on the relative sizes of the table and the index. K - ** is smaller for smaller indices, thus favoring them. - */ - pNew->rRun = sqlite3LogEstAdd(rSize,rLogSize) + 1 + - (15*pProbe->szIdxRow)/pTab->szTabRow; - }else{ - /* TUNING: Cost of scanning a non-covering index is (N+1)*log2(N) - ** which we will simplify to just N*log2(N) */ - pNew->rRun = rSize + rLogSize; + + /* The cost of visiting the index rows is N*K, where K is + ** between 1.1 and 3.0, depending on the relative sizes of the + ** index and table rows. If this is a non-covering index scan, + ** also add the cost of visiting table rows (N*3.0). */ + pNew->rRun = rSize + 1 + (15*pProbe->szIdxRow)/pTab->szTabRow; + if( m!=0 ){ + pNew->rRun = sqlite3LogEstAdd(pNew->rRun, rSize+16); } + ApplyCostMultiplier(pNew->rRun, pTab->costMult); whereLoopOutputAdjust(pWC, pNew); rc = whereLoopInsert(pBuilder, pNew); pNew->nOut = rSize; @@ -4506,8 +4932,8 @@ static int whereLoopAddVirtual( pNew->u.vtab.needFree = pIdxInfo->needToFreeIdxStr; pIdxInfo->needToFreeIdxStr = 0; pNew->u.vtab.idxStr = pIdxInfo->idxStr; - pNew->u.vtab.isOrdered = (u8)((pIdxInfo->nOrderBy!=0) - && pIdxInfo->orderByConsumed); + pNew->u.vtab.isOrdered = (i8)(pIdxInfo->orderByConsumed ? + pIdxInfo->nOrderBy : 0); pNew->rSetup = 0; pNew->rRun = sqlite3LogEstFromDouble(pIdxInfo->estimatedCost); pNew->nOut = sqlite3LogEst(pIdxInfo->estimatedRows); @@ -4539,7 +4965,7 @@ static int whereLoopAddOr(WhereLoopBuilder *pBuilder, Bitmask mExtra){ int iCur; WhereClause tempWC; WhereLoopBuilder sSubBuild; - WhereOrSet sSum, sCur, sPrev; + WhereOrSet sSum, sCur; struct SrcList_item *pItem; pWC = pBuilder->pWC; @@ -4548,7 +4974,6 @@ static int whereLoopAddOr(WhereLoopBuilder *pBuilder, Bitmask mExtra){ pNew = pBuilder->pNew; memset(&sSum, 0, sizeof(sSum)); pItem = pWInfo->pTabList->a + pNew->iTab; - if( !HasRowid(pItem->pTab) ) return SQLITE_OK; iCur = pItem->iCursor; for(pTerm=pWC->a; pTerm<pWCEnd && rc==SQLITE_OK; pTerm++){ @@ -4595,6 +5020,7 @@ static int whereLoopAddOr(WhereLoopBuilder *pBuilder, Bitmask mExtra){ whereOrMove(&sSum, &sCur); once = 0; }else{ + WhereOrSet sPrev; whereOrMove(&sPrev, &sSum); sSum.n = 0; for(i=0; i<sPrev.n; i++){ @@ -4613,8 +5039,19 @@ static int whereLoopAddOr(WhereLoopBuilder *pBuilder, Bitmask mExtra){ pNew->iSortIdx = 0; memset(&pNew->u, 0, sizeof(pNew->u)); for(i=0; rc==SQLITE_OK && i<sSum.n; i++){ - /* TUNING: Multiple by 3.5 for the secondary table lookup */ - pNew->rRun = sSum.a[i].rRun + 18; + /* TUNING: Currently sSum.a[i].rRun is set to the sum of the costs + ** of all sub-scans required by the OR-scan. However, due to rounding + ** errors, it may be that the cost of the OR-scan is equal to its + ** most expensive sub-scan. Add the smallest possible penalty + ** (equivalent to multiplying the cost by 1.07) to ensure that + ** this does not happen. Otherwise, for WHERE clauses such as the + ** following where there is an index on "y": + ** + ** WHERE likelihood(x=?, 0.99) OR y=? + ** + ** the planner may elect to "OR" together a full-table scan and an + ** index lookup. And other similarly odd results. */ + pNew->rRun = sSum.a[i].rRun + 1; pNew->nOut = sSum.a[i].nOut; pNew->prereq = sSum.a[i].prereq; rc = whereLoopInsert(pBuilder, pNew); @@ -4668,21 +5105,21 @@ static int whereLoopAddAll(WhereLoopBuilder *pBuilder){ /* ** Examine a WherePath (with the addition of the extra WhereLoop of the 5th ** parameters) to see if it outputs rows in the requested ORDER BY -** (or GROUP BY) without requiring a separate sort operation. Return: +** (or GROUP BY) without requiring a separate sort operation. Return N: ** -** 0: ORDER BY is not satisfied. Sorting required -** 1: ORDER BY is satisfied. Omit sorting -** -1: Unknown at this time +** N>0: N terms of the ORDER BY clause are satisfied +** N==0: No terms of the ORDER BY clause are satisfied +** N<0: Unknown yet how many terms of ORDER BY might be satisfied. ** ** Note that processing for WHERE_GROUPBY and WHERE_DISTINCTBY is not as ** strict. With GROUP BY and DISTINCT the only requirement is that ** equivalent rows appear immediately adjacent to one another. GROUP BY -** and DISTINT do not require rows to appear in any particular order as long +** 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 ** the pOrderBy terms can be matched in any order. With ORDER BY, the ** pOrderBy terms must be matched in strict left-to-right order. */ -static int wherePathSatisfiesOrderBy( +static i8 wherePathSatisfiesOrderBy( WhereInfo *pWInfo, /* The WHERE clause */ ExprList *pOrderBy, /* ORDER BY or GROUP BY or DISTINCT clause to check */ WherePath *pPath, /* The WherePath to check */ @@ -4738,14 +5175,6 @@ static int wherePathSatisfiesOrderBy( */ assert( pOrderBy!=0 ); - - /* Sortability of virtual tables is determined by the xBestIndex method - ** of the virtual table itself */ - if( pLast->wsFlags & WHERE_VIRTUALTABLE ){ - testcase( nLoop>0 ); /* True when outer loops are one-row and match - ** no ORDER BY terms */ - return pLast->u.vtab.isOrdered; - } if( nLoop && OptimizationDisabled(db, SQLITE_OrderByIdxJoin) ) return 0; nOrderBy = pOrderBy->nExpr; @@ -4758,7 +5187,10 @@ static int wherePathSatisfiesOrderBy( for(iLoop=0; isOrderDistinct && obSat<obDone && iLoop<=nLoop; iLoop++){ if( iLoop>0 ) ready |= pLoop->maskSelf; pLoop = iLoop<nLoop ? pPath->aLoop[iLoop] : pLast; - assert( (pLoop->wsFlags & WHERE_VIRTUALTABLE)==0 ); + if( pLoop->wsFlags & WHERE_VIRTUALTABLE ){ + if( pLoop->u.vtab.isOrdered ) obSat = obDone; + break; + } iCur = pWInfo->pTabList->a[pLoop->iTab].iCursor; /* Mark off any ORDER BY term X that is a column in the table of @@ -4799,7 +5231,7 @@ static int 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 @@ -4846,7 +5278,7 @@ static int wherePathSatisfiesOrderBy( } /* Find the ORDER BY term that corresponds to the j-th column - ** of the index and and mark that ORDER BY term off + ** of the index and mark that ORDER BY term off */ bOnce = 1; isMatch = 0; @@ -4867,23 +5299,23 @@ static int wherePathSatisfiesOrderBy( isMatch = 1; break; } + if( isMatch && (pWInfo->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 ){ + if( (rev ^ revIdx)!=pOrderBy->a[i].sortOrder ) isMatch = 0; + }else{ + rev = revIdx ^ pOrderBy->a[i].sortOrder; + if( rev ) *pRevMask |= MASKBIT(iLoop); + revSet = 1; + } + } if( isMatch ){ if( iColumn<0 ){ testcase( distinctColumns==0 ); distinctColumns = 1; } obSat |= MASKBIT(i); - if( (pWInfo->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 ){ - if( (rev ^ revIdx)!=pOrderBy->a[i].sortOrder ) return 0; - }else{ - rev = revIdx ^ pOrderBy->a[i].sortOrder; - if( rev ) *pRevMask |= MASKBIT(iLoop); - revSet = 1; - } - } }else{ /* No match found */ if( j==0 || j<nKeyCol ){ @@ -4915,11 +5347,47 @@ static int wherePathSatisfiesOrderBy( } } } /* End the loop over all WhereLoops from outer-most down to inner-most */ - if( obSat==obDone ) return 1; - if( !isOrderDistinct ) return 0; + if( obSat==obDone ) return (i8)nOrderBy; + if( !isOrderDistinct ){ + for(i=nOrderBy-1; i>0; i--){ + Bitmask m = MASKBIT(i) - 1; + if( (obSat&m)==m ) return i; + } + return 0; + } return -1; } + +/* +** If the WHERE_GROUPBY flag is set in the mask passed to sqlite3WhereBegin(), +** the planner assumes that the specified pOrderBy list is actually a GROUP +** BY clause - and so any order that groups rows as required satisfies the +** request. +** +** Normally, in this case it is not possible for the caller to determine +** whether or not the rows are really being delivered in sorted order, or +** just in some other order that provides the required grouping. However, +** if the WHERE_SORTBYGROUP flag is also passed to sqlite3WhereBegin(), then +** this function may be called on the returned WhereInfo object. It returns +** true if the rows really will be sorted in the specified order, or false +** otherwise. +** +** For example, assuming: +** +** CREATE INDEX i1 ON t1(x, Y); +** +** then +** +** SELECT * FROM t1 GROUP BY x,y ORDER BY x,y; -- IsSorted()==1 +** SELECT * FROM t1 GROUP BY y,x ORDER BY y,x; -- IsSorted()==0 +*/ +int sqlite3WhereIsSorted(WhereInfo *pWInfo){ + assert( pWInfo->wctrlFlags & WHERE_GROUPBY ); + assert( pWInfo->wctrlFlags & WHERE_SORTBYGROUP ); + return pWInfo->sorted; +} + #ifdef WHERETRACE_ENABLED /* For debugging use only: */ static const char *wherePathName(WherePath *pPath, int nLoop, WhereLoop *pLast){ @@ -4932,6 +5400,44 @@ 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 @@ -4953,11 +5459,9 @@ static int wherePathSolver(WhereInfo *pWInfo, LogEst nRowEst){ int iLoop; /* Loop counter over the terms of the join */ int ii, jj; /* Loop counters */ int mxI = 0; /* Index of next entry to replace */ - LogEst rCost; /* Cost of a path */ - LogEst nOut; /* Number of outputs */ + int nOrderBy; /* Number of ORDER BY clause terms */ LogEst mxCost = 0; /* Maximum cost of a set of paths */ - LogEst mxOut = 0; /* Maximum nOut value on the set of paths */ - LogEst rSortCost; /* Cost to do a sort */ + 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 */ @@ -4965,7 +5469,9 @@ 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; @@ -4973,13 +5479,25 @@ static int wherePathSolver(WhereInfo *pWInfo, LogEst nRowEst){ /* TUNING: For simple queries, only the best path is tracked. ** For 2-way joins, the 5 best paths are followed. ** For joins of 3 or more tables, track the 10 best paths */ - mxChoice = (nLoop==1) ? 1 : (nLoop==2 ? 5 : 10); + 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; @@ -4988,6 +5506,18 @@ 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. ** @@ -4996,19 +5526,15 @@ 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 */ - rSortCost = 0; - if( pWInfo->pOrderBy==0 || nRowEst==0 ){ - aFrom[0].isOrderedValid = 1; - }else{ - /* TUNING: Estimated cost of sorting is 48*N*log2(N) where N is the - ** number of output rows. The 48 is the expected size of a row to sort. - ** FIXME: compute a better estimate of the 48 multiplier based on the - ** result set expressions. */ - rSortCost = nRowEst + estLog(nRowEst); - WHERETRACE(0x002,("---- sort cost=%-3d\n", rSortCost)); + 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 @@ -5018,60 +5544,82 @@ 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; - u8 isOrderedValid = pFrom->isOrderedValid; - u8 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( !isOrderedValid ){ - switch( wherePathSatisfiesOrderBy(pWInfo, + if( isOrdered<0 ){ + isOrdered = wherePathSatisfiesOrderBy(pWInfo, pWInfo->pOrderBy, pFrom, pWInfo->wctrlFlags, - iLoop, pWLoop, &revMask) ){ - case 1: /* Yes. pFrom+pWLoop does satisfy the ORDER BY clause */ - isOrdered = 1; - isOrderedValid = 1; - break; - case 0: /* No. pFrom+pWLoop will require a separate sort */ - isOrdered = 0; - isOrderedValid = 1; - rCost = sqlite3LogEstAdd(rCost, rSortCost); - break; - default: /* Cannot tell yet. Try again on the next iteration */ - break; - } + iLoop, pWLoop, &revMask); }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->isOrderedValid==isOrderedValid - && ((pTo->rCost<=rCost && pTo->nRow<=nOut) || - (pTo->rCost>=rCost && pTo->nRow>=nOut)) + && ((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", wherePathName(pFrom, iLoop, pWLoop), rCost, nOut, - isOrderedValid ? (isOrdered ? 'Y' : 'N') : '?'); + isOrdered>=0 ? isOrdered+'0' : '?'); } #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++; @@ -5084,36 +5632,42 @@ static int wherePathSolver(WhereInfo *pWInfo, LogEst nRowEst){ if( sqlite3WhereTrace&0x4 ){ sqlite3DebugPrintf("New %s cost=%-3d,%3d order=%c\n", wherePathName(pFrom, iLoop, pWLoop), rCost, nOut, - isOrderedValid ? (isOrdered ? 'Y' : 'N') : '?'); + isOrdered>=0 ? isOrdered+'0' : '?'); } #endif }else{ - if( pTo->rCost<=rCost && pTo->nRow<=nOut ){ + /* 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( "Skip %s cost=%-3d,%3d order=%c", wherePathName(pFrom, iLoop, pWLoop), rCost, nOut, - isOrderedValid ? (isOrdered ? 'Y' : 'N') : '?'); + isOrdered>=0 ? isOrdered+'0' : '?'); sqlite3DebugPrintf(" vs %s cost=%-3d,%d order=%c\n", wherePathName(pTo, iLoop+1, 0), pTo->rCost, pTo->nRow, - pTo->isOrderedValid ? (pTo->isOrdered ? 'Y' : 'N') : '?'); + 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( "Update %s cost=%-3d,%3d order=%c", wherePathName(pFrom, iLoop, pWLoop), rCost, nOut, - isOrderedValid ? (isOrdered ? 'Y' : 'N') : '?'); + isOrdered>=0 ? isOrdered+'0' : '?'); sqlite3DebugPrintf(" was %s cost=%-3d,%3d order=%c\n", wherePathName(pTo, iLoop+1, 0), pTo->rCost, pTo->nRow, - pTo->isOrderedValid ? (pTo->isOrdered ? 'Y' : 'N') : '?'); + pTo->isOrdered>=0 ? pTo->isOrdered+'0' : '?'); } #endif } @@ -5122,18 +5676,20 @@ static int wherePathSolver(WhereInfo *pWInfo, LogEst nRowEst){ pTo->revLoop = revMask; pTo->nRow = nOut; pTo->rCost = rCost; - pTo->isOrderedValid = isOrderedValid; + 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; - mxOut = aTo[0].nRow; + mxUnsorted = aTo[0].nRow; for(jj=1, pTo=&aTo[1]; jj<mxChoice; jj++, pTo++){ - if( pTo->rCost>mxCost || (pTo->rCost==mxCost && pTo->nRow>mxOut) ){ + if( pTo->rCost>mxCost + || (pTo->rCost==mxCost && pTo->rUnsorted>mxUnsorted) + ){ mxCost = pTo->rCost; - mxOut = pTo->nRow; + mxUnsorted = pTo->rUnsorted; mxI = jj; } } @@ -5147,8 +5703,8 @@ static int wherePathSolver(WhereInfo *pWInfo, LogEst nRowEst){ 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->isOrderedValid ? (pTo->isOrdered ? 'Y' : 'N') : '?'); - if( pTo->isOrderedValid && pTo->isOrdered ){ + pTo->isOrdered>=0 ? (pTo->isOrdered+'0') : '?'); + if( pTo->isOrdered>0 ){ sqlite3DebugPrintf(" rev=0x%llx\n", pTo->revLoop); }else{ sqlite3DebugPrintf("\n"); @@ -5191,16 +5747,33 @@ static int wherePathSolver(WhereInfo *pWInfo, LogEst nRowEst){ Bitmask notUsed; int rc = wherePathSatisfiesOrderBy(pWInfo, pWInfo->pResultSet, pFrom, WHERE_DISTINCTBY, nLoop-1, pFrom->aLoop[nLoop-1], ¬Used); - if( rc==1 ) pWInfo->eDistinct = WHERE_DISTINCT_ORDERED; + if( rc==pWInfo->pResultSet->nExpr ){ + pWInfo->eDistinct = WHERE_DISTINCT_ORDERED; + } } - if( pFrom->isOrdered ){ + if( pWInfo->pOrderBy ){ if( pWInfo->wctrlFlags & WHERE_DISTINCTBY ){ - pWInfo->eDistinct = WHERE_DISTINCT_ORDERED; + if( pFrom->isOrdered==pWInfo->pOrderBy->nExpr ){ + pWInfo->eDistinct = WHERE_DISTINCT_ORDERED; + } }else{ - pWInfo->bOBSat = 1; + pWInfo->nOBSat = pFrom->isOrdered; + if( pWInfo->nOBSat<0 ) pWInfo->nOBSat = 0; pWInfo->revMask = pFrom->revLoop; } + if( (pWInfo->wctrlFlags & WHERE_SORTBYGROUP) + && pWInfo->nOBSat==pWInfo->pOrderBy->nExpr + ){ + Bitmask notUsed = 0; + int nOrder = wherePathSatisfiesOrderBy(pWInfo, pWInfo->pOrderBy, + pFrom, 0, nLoop-1, pFrom->aLoop[nLoop-1], ¬Used + ); + assert( pWInfo->sorted==0 ); + pWInfo->sorted = (nOrder==pWInfo->pOrderBy->nExpr); + } } + + pWInfo->nRowOut = pFrom->nRow; /* Free temporary memory and return success */ @@ -5254,7 +5827,7 @@ static int whereShortCut(WhereLoopBuilder *pBuilder){ 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; @@ -5282,7 +5855,7 @@ static int whereShortCut(WhereLoopBuilder *pBuilder){ pLoop->maskSelf = getMask(&pWInfo->sMaskSet, iCur); pWInfo->a[0].iTabCur = iCur; pWInfo->nRowOut = 1; - if( pWInfo->pOrderBy ) pWInfo->bOBSat = 1; + if( pWInfo->pOrderBy ) pWInfo->nOBSat = pWInfo->pOrderBy->nExpr; if( pWInfo->wctrlFlags & WHERE_WANT_DISTINCT ){ pWInfo->eDistinct = WHERE_DISTINCT_UNIQUE; } @@ -5386,7 +5959,7 @@ WhereInfo *sqlite3WhereBegin( Parse *pParse, /* The parser context */ SrcList *pTabList, /* FROM clause: A list of all tables to be scanned */ Expr *pWhere, /* The WHERE clause */ - ExprList *pOrderBy, /* An ORDER BY clause, or NULL */ + ExprList *pOrderBy, /* An ORDER BY (or GROUP BY) clause, or NULL */ ExprList *pResultSet, /* Result set of the query */ u16 wctrlFlags, /* One of the WHERE_* flags defined in sqliteInt.h */ int iIdxCur /* If WHERE_ONETABLE_ONLY is set, index cursor number */ @@ -5408,6 +5981,10 @@ WhereInfo *sqlite3WhereBegin( /* Variable initialization */ db = pParse->db; memset(&sWLB, 0, sizeof(sWLB)); + + /* An ORDER/GROUP BY clause of more than 63 terms cannot be optimized */ + testcase( pOrderBy && pOrderBy->nExpr==BMS-1 ); + if( pOrderBy && pOrderBy->nExpr>=BMS ) pOrderBy = 0; sWLB.pOrderBy = pOrderBy; /* Disable the DISTINCT optimization if SQLITE_DistinctOpt is set via @@ -5452,7 +6029,7 @@ WhereInfo *sqlite3WhereBegin( pWInfo->pTabList = pTabList; pWInfo->pOrderBy = pOrderBy; pWInfo->pResultSet = pResultSet; - pWInfo->iBreak = sqlite3VdbeMakeLabel(v); + pWInfo->iBreak = pWInfo->iContinue = sqlite3VdbeMakeLabel(v); pWInfo->wctrlFlags = wctrlFlags; pWInfo->savedNQueryLoop = pParse->nQueryLoop; pMaskSet = &pWInfo->sMaskSet; @@ -5486,7 +6063,7 @@ WhereInfo *sqlite3WhereBegin( /* Special case: No FROM clause */ if( nTabList==0 ){ - if( pOrderBy ) pWInfo->bOBSat = 1; + if( pOrderBy ) pWInfo->nOBSat = pOrderBy->nExpr; if( wctrlFlags & WHERE_WANT_DISTINCT ){ pWInfo->eDistinct = WHERE_DISTINCT_UNIQUE; } @@ -5597,8 +6174,8 @@ WhereInfo *sqlite3WhereBegin( if( sqlite3WhereTrace ){ int ii; sqlite3DebugPrintf("---- Solution nRow=%d", pWInfo->nRowOut); - if( pWInfo->bOBSat ){ - sqlite3DebugPrintf(" ORDERBY=0x%llx", pWInfo->revMask); + if( pWInfo->nOBSat>0 ){ + sqlite3DebugPrintf(" ORDERBY=%d,0x%llx", pWInfo->nOBSat, pWInfo->revMask); } switch( pWInfo->eDistinct ){ case WHERE_DISTINCT_UNIQUE: { @@ -5721,7 +6298,14 @@ WhereInfo *sqlite3WhereBegin( int op = OP_OpenRead; /* iIdxCur is always set if to a positive value if ONEPASS is possible */ assert( iIdxCur!=0 || (pWInfo->wctrlFlags & WHERE_ONEPASS_DESIRED)==0 ); - if( pWInfo->okOnePass ){ + if( !HasRowid(pTab) && IsPrimaryKeyIndex(pIx) + && (wctrlFlags & WHERE_ONETABLE_ONLY)!=0 + ){ + /* This is one term of an OR-optimization using the PRIMARY KEY of a + ** WITHOUT ROWID table. No need for a separate index */ + iIndexCur = pLevel->iTabCur; + op = 0; + }else if( pWInfo->okOnePass ){ Index *pJ = pTabItem->pTab->pIndex; iIndexCur = iIdxCur; assert( wctrlFlags & WHERE_ONEPASS_DESIRED ); @@ -5733,15 +6317,18 @@ 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++; } pLevel->iIdxCur = iIndexCur; assert( pIx->pSchema==pTab->pSchema ); assert( iIndexCur>=0 ); - sqlite3VdbeAddOp3(v, op, iIndexCur, pIx->tnum, iDb); - sqlite3VdbeSetP4KeyInfo(pParse, pIx); - VdbeComment((v, "%s", pIx->zName)); + if( op ){ + sqlite3VdbeAddOp3(v, op, iIndexCur, pIx->tnum, iDb); + sqlite3VdbeSetP4KeyInfo(pParse, pIx); + VdbeComment((v, "%s", pIx->zName)); + } } if( iDb>=0 ) sqlite3CodeVerifySchema(pParse, iDb); notReady &= ~getMask(&pWInfo->sMaskSet, pTabItem->iCursor); |