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Diffstat (limited to 'lib/libsqlite3/src/where.c')
| -rw-r--r-- | lib/libsqlite3/src/where.c | 4608 |
1 files changed, 0 insertions, 4608 deletions
diff --git a/lib/libsqlite3/src/where.c b/lib/libsqlite3/src/where.c deleted file mode 100644 index 0adc698401c..00000000000 --- a/lib/libsqlite3/src/where.c +++ /dev/null @@ -1,4608 +0,0 @@ -/* -** 2001 September 15 -** -** The author disclaims copyright to this source code. In place of -** a legal notice, here is a blessing: -** -** May you do good and not evil. -** May you find forgiveness for yourself and forgive others. -** May you share freely, never taking more than you give. -** -************************************************************************* -** This module contains C code that generates VDBE code used to process -** the WHERE clause of SQL statements. This module is responsible for -** generating the code that loops through a table looking for applicable -** rows. Indices are selected and used to speed the search when doing -** so is applicable. Because this module is responsible for selecting -** indices, you might also think of this module as the "query optimizer". -*/ -#include "sqliteInt.h" -#include "whereInt.h" - -/* Forward declaration of methods */ -static int whereLoopResize(sqlite3*, WhereLoop*, int); - -/* Test variable that can be set to enable WHERE tracing */ -#if defined(SQLITE_TEST) || defined(SQLITE_DEBUG) -/***/ int sqlite3WhereTrace = 0; -#endif - - -/* -** Return the estimated number of output rows from a WHERE clause -*/ -u64 sqlite3WhereOutputRowCount(WhereInfo *pWInfo){ - return sqlite3LogEstToInt(pWInfo->nRowOut); -} - -/* -** Return one of the WHERE_DISTINCT_xxxxx values to indicate how this -** WHERE clause returns outputs for DISTINCT processing. -*/ -int sqlite3WhereIsDistinct(WhereInfo *pWInfo){ - return pWInfo->eDistinct; -} - -/* -** Return TRUE if the WHERE clause returns rows in ORDER BY order. -** Return FALSE if the output needs to be sorted. -*/ -int sqlite3WhereIsOrdered(WhereInfo *pWInfo){ - return pWInfo->nOBSat; -} - -/* -** Return the VDBE address or label to jump to in order to continue -** immediately with the next row of a WHERE clause. -*/ -int sqlite3WhereContinueLabel(WhereInfo *pWInfo){ - assert( pWInfo->iContinue!=0 ); - return pWInfo->iContinue; -} - -/* -** Return the VDBE address or label to jump to in order to break -** out of a WHERE loop. -*/ -int sqlite3WhereBreakLabel(WhereInfo *pWInfo){ - return pWInfo->iBreak; -} - -/* -** Return ONEPASS_OFF (0) if an UPDATE or DELETE statement is unable to -** operate directly on the rowis returned by a WHERE clause. Return -** ONEPASS_SINGLE (1) if the statement can operation directly because only -** a single row is to be changed. Return ONEPASS_MULTI (2) if the one-pass -** optimization can be used on multiple -** -** If the ONEPASS optimization is used (if this routine returns true) -** then also write the indices of open cursors used by ONEPASS -** into aiCur[0] and aiCur[1]. iaCur[0] gets the cursor of the data -** table and iaCur[1] gets the cursor used by an auxiliary index. -** Either value may be -1, indicating that cursor is not used. -** Any cursors returned will have been opened for writing. -** -** aiCur[0] and aiCur[1] both get -1 if the where-clause logic is -** unable to use the ONEPASS optimization. -*/ -int sqlite3WhereOkOnePass(WhereInfo *pWInfo, int *aiCur){ - memcpy(aiCur, pWInfo->aiCurOnePass, sizeof(int)*2); -#ifdef WHERETRACE_ENABLED - if( sqlite3WhereTrace && pWInfo->eOnePass!=ONEPASS_OFF ){ - sqlite3DebugPrintf("%s cursors: %d %d\n", - pWInfo->eOnePass==ONEPASS_SINGLE ? "ONEPASS_SINGLE" : "ONEPASS_MULTI", - aiCur[0], aiCur[1]); - } -#endif - return pWInfo->eOnePass; -} - -/* -** Move the content of pSrc into pDest -*/ -static void whereOrMove(WhereOrSet *pDest, WhereOrSet *pSrc){ - pDest->n = pSrc->n; - memcpy(pDest->a, pSrc->a, pDest->n*sizeof(pDest->a[0])); -} - -/* -** Try to insert a new prerequisite/cost entry into the WhereOrSet pSet. -** -** The new entry might overwrite an existing entry, or it might be -** appended, or it might be discarded. Do whatever is the right thing -** so that pSet keeps the N_OR_COST best entries seen so far. -*/ -static int whereOrInsert( - WhereOrSet *pSet, /* The WhereOrSet to be updated */ - Bitmask prereq, /* Prerequisites of the new entry */ - LogEst rRun, /* Run-cost of the new entry */ - LogEst nOut /* Number of outputs for the new entry */ -){ - u16 i; - WhereOrCost *p; - for(i=pSet->n, p=pSet->a; i>0; i--, p++){ - if( rRun<=p->rRun && (prereq & p->prereq)==prereq ){ - goto whereOrInsert_done; - } - if( p->rRun<=rRun && (p->prereq & prereq)==p->prereq ){ - return 0; - } - } - if( pSet->n<N_OR_COST ){ - p = &pSet->a[pSet->n++]; - p->nOut = nOut; - }else{ - p = pSet->a; - for(i=1; i<pSet->n; i++){ - if( p->rRun>pSet->a[i].rRun ) p = pSet->a + i; - } - if( p->rRun<=rRun ) return 0; - } -whereOrInsert_done: - p->prereq = prereq; - p->rRun = rRun; - if( p->nOut>nOut ) p->nOut = nOut; - return 1; -} - -/* -** Return the bitmask for the given cursor number. Return 0 if -** iCursor is not in the set. -*/ -Bitmask sqlite3WhereGetMask(WhereMaskSet *pMaskSet, int iCursor){ - int i; - assert( pMaskSet->n<=(int)sizeof(Bitmask)*8 ); - for(i=0; i<pMaskSet->n; i++){ - if( pMaskSet->ix[i]==iCursor ){ - return MASKBIT(i); - } - } - return 0; -} - -/* -** Create a new mask for cursor iCursor. -** -** There is one cursor per table in the FROM clause. The number of -** tables in the FROM clause is limited by a test early in the -** sqlite3WhereBegin() routine. So we know that the pMaskSet->ix[] -** array will never overflow. -*/ -static void createMask(WhereMaskSet *pMaskSet, int iCursor){ - assert( pMaskSet->n < ArraySize(pMaskSet->ix) ); - pMaskSet->ix[pMaskSet->n++] = iCursor; -} - -/* -** Advance to the next WhereTerm that matches according to the criteria -** established when the pScan object was initialized by whereScanInit(). -** Return NULL if there are no more matching WhereTerms. -*/ -static WhereTerm *whereScanNext(WhereScan *pScan){ - int iCur; /* The cursor on the LHS of the term */ - i16 iColumn; /* The column on the LHS of the term. -1 for IPK */ - Expr *pX; /* An expression being tested */ - WhereClause *pWC; /* Shorthand for pScan->pWC */ - WhereTerm *pTerm; /* The term being tested */ - int k = pScan->k; /* Where to start scanning */ - - while( pScan->iEquiv<=pScan->nEquiv ){ - iCur = pScan->aiCur[pScan->iEquiv-1]; - iColumn = pScan->aiColumn[pScan->iEquiv-1]; - if( iColumn==XN_EXPR && pScan->pIdxExpr==0 ) return 0; - while( (pWC = pScan->pWC)!=0 ){ - for(pTerm=pWC->a+k; k<pWC->nTerm; k++, pTerm++){ - if( pTerm->leftCursor==iCur - && pTerm->u.leftColumn==iColumn - && (iColumn!=XN_EXPR - || sqlite3ExprCompare(pTerm->pExpr->pLeft,pScan->pIdxExpr,iCur)==0) - && (pScan->iEquiv<=1 || !ExprHasProperty(pTerm->pExpr, EP_FromJoin)) - ){ - if( (pTerm->eOperator & WO_EQUIV)!=0 - && pScan->nEquiv<ArraySize(pScan->aiCur) - && (pX = sqlite3ExprSkipCollate(pTerm->pExpr->pRight))->op==TK_COLUMN - ){ - int j; - for(j=0; j<pScan->nEquiv; j++){ - if( pScan->aiCur[j]==pX->iTable - && pScan->aiColumn[j]==pX->iColumn ){ - break; - } - } - if( j==pScan->nEquiv ){ - pScan->aiCur[j] = pX->iTable; - pScan->aiColumn[j] = pX->iColumn; - pScan->nEquiv++; - } - } - if( (pTerm->eOperator & pScan->opMask)!=0 ){ - /* Verify the affinity and collating sequence match */ - if( pScan->zCollName && (pTerm->eOperator & WO_ISNULL)==0 ){ - CollSeq *pColl; - Parse *pParse = pWC->pWInfo->pParse; - pX = pTerm->pExpr; - if( !sqlite3IndexAffinityOk(pX, pScan->idxaff) ){ - continue; - } - assert(pX->pLeft); - pColl = sqlite3BinaryCompareCollSeq(pParse, - pX->pLeft, pX->pRight); - if( pColl==0 ) pColl = pParse->db->pDfltColl; - if( sqlite3StrICmp(pColl->zName, pScan->zCollName) ){ - continue; - } - } - if( (pTerm->eOperator & (WO_EQ|WO_IS))!=0 - && (pX = pTerm->pExpr->pRight)->op==TK_COLUMN - && pX->iTable==pScan->aiCur[0] - && pX->iColumn==pScan->aiColumn[0] - ){ - testcase( pTerm->eOperator & WO_IS ); - continue; - } - pScan->k = k+1; - return pTerm; - } - } - } - pScan->pWC = pScan->pWC->pOuter; - k = 0; - } - pScan->pWC = pScan->pOrigWC; - k = 0; - pScan->iEquiv++; - } - return 0; -} - -/* -** Initialize a WHERE clause scanner object. Return a pointer to the -** first match. Return NULL if there are no matches. -** -** The scanner will be searching the WHERE clause pWC. It will look -** for terms of the form "X <op> <expr>" where X is column iColumn of table -** iCur. The <op> must be one of the operators described by opMask. -** -** If the search is for X and the WHERE clause contains terms of the -** form X=Y then this routine might also return terms of the form -** "Y <op> <expr>". The number of levels of transitivity is limited, -** but is enough to handle most commonly occurring SQL statements. -** -** If X is not the INTEGER PRIMARY KEY then X must be compatible with -** index pIdx. -*/ -static WhereTerm *whereScanInit( - WhereScan *pScan, /* The WhereScan object being initialized */ - WhereClause *pWC, /* The WHERE clause to be scanned */ - int iCur, /* Cursor to scan for */ - int iColumn, /* Column to scan for */ - u32 opMask, /* Operator(s) to scan for */ - Index *pIdx /* Must be compatible with this index */ -){ - int j = 0; - - /* memset(pScan, 0, sizeof(*pScan)); */ - pScan->pOrigWC = pWC; - pScan->pWC = pWC; - pScan->pIdxExpr = 0; - if( pIdx ){ - j = iColumn; - iColumn = pIdx->aiColumn[j]; - if( iColumn==XN_EXPR ) pScan->pIdxExpr = pIdx->aColExpr->a[j].pExpr; - } - if( pIdx && iColumn>=0 ){ - pScan->idxaff = pIdx->pTable->aCol[iColumn].affinity; - pScan->zCollName = pIdx->azColl[j]; - }else{ - pScan->idxaff = 0; - pScan->zCollName = 0; - } - pScan->opMask = opMask; - pScan->k = 0; - pScan->aiCur[0] = iCur; - pScan->aiColumn[0] = iColumn; - pScan->nEquiv = 1; - pScan->iEquiv = 1; - return whereScanNext(pScan); -} - -/* -** Search for a term in the WHERE clause that is of the form "X <op> <expr>" -** where X is a reference to the iColumn of table iCur and <op> is one of -** the WO_xx operator codes specified by the op parameter. -** Return a pointer to the term. Return 0 if not found. -** -** If pIdx!=0 then search for terms matching the iColumn-th column of pIdx -** rather than the iColumn-th column of table iCur. -** -** The term returned might by Y=<expr> if there is another constraint in -** the WHERE clause that specifies that X=Y. Any such constraints will be -** identified by the WO_EQUIV bit in the pTerm->eOperator field. The -** aiCur[]/iaColumn[] arrays hold X and all its equivalents. There are 11 -** slots in aiCur[]/aiColumn[] so that means we can look for X plus up to 10 -** other equivalent values. Hence a search for X will return <expr> if X=A1 -** and A1=A2 and A2=A3 and ... and A9=A10 and A10=<expr>. -** -** If there are multiple terms in the WHERE clause of the form "X <op> <expr>" -** then try for the one with no dependencies on <expr> - in other words where -** <expr> is a constant expression of some kind. Only return entries of -** the form "X <op> Y" where Y is a column in another table if no terms of -** the form "X <op> <const-expr>" exist. If no terms with a constant RHS -** exist, try to return a term that does not use WO_EQUIV. -*/ -WhereTerm *sqlite3WhereFindTerm( - WhereClause *pWC, /* The WHERE clause to be searched */ - int iCur, /* Cursor number of LHS */ - int iColumn, /* Column number of LHS */ - Bitmask notReady, /* RHS must not overlap with this mask */ - u32 op, /* Mask of WO_xx values describing operator */ - Index *pIdx /* Must be compatible with this index, if not NULL */ -){ - WhereTerm *pResult = 0; - WhereTerm *p; - WhereScan scan; - - p = whereScanInit(&scan, pWC, iCur, iColumn, op, pIdx); - op &= WO_EQ|WO_IS; - while( p ){ - if( (p->prereqRight & notReady)==0 ){ - if( p->prereqRight==0 && (p->eOperator&op)!=0 ){ - testcase( p->eOperator & WO_IS ); - return p; - } - if( pResult==0 ) pResult = p; - } - p = whereScanNext(&scan); - } - return pResult; -} - -/* -** 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 -** no expression is found, -1 is returned. -*/ -static int findIndexCol( - Parse *pParse, /* Parse context */ - ExprList *pList, /* Expression list to search */ - int iBase, /* Cursor for table associated with pIdx */ - Index *pIdx, /* Index to match column of */ - int iCol /* Column of index to match */ -){ - int i; - const char *zColl = pIdx->azColl[iCol]; - - for(i=0; i<pList->nExpr; i++){ - Expr *p = sqlite3ExprSkipCollate(pList->a[i].pExpr); - if( p->op==TK_COLUMN - && p->iColumn==pIdx->aiColumn[iCol] - && p->iTable==iBase - ){ - CollSeq *pColl = sqlite3ExprCollSeq(pParse, pList->a[i].pExpr); - if( pColl && 0==sqlite3StrICmp(pColl->zName, zColl) ){ - return i; - } - } - } - - return -1; -} - -/* -** Return TRUE if the iCol-th column of index pIdx is NOT NULL -*/ -static int indexColumnNotNull(Index *pIdx, int iCol){ - int j; - assert( pIdx!=0 ); - assert( iCol>=0 && iCol<pIdx->nColumn ); - j = pIdx->aiColumn[iCol]; - if( j>=0 ){ - return pIdx->pTable->aCol[j].notNull; - }else if( j==(-1) ){ - return 1; - }else{ - assert( j==(-2) ); - return 0; /* Assume an indexed expression can always yield a NULL */ - - } -} - -/* -** Return true if the DISTINCT expression-list passed as the third argument -** is redundant. -** -** A DISTINCT list is redundant if any subset of the columns in the -** DISTINCT list are collectively unique and individually non-null. -*/ -static int isDistinctRedundant( - Parse *pParse, /* Parsing context */ - SrcList *pTabList, /* The FROM clause */ - WhereClause *pWC, /* The WHERE clause */ - ExprList *pDistinct /* The result set that needs to be DISTINCT */ -){ - Table *pTab; - Index *pIdx; - int i; - int iBase; - - /* If there is more than one table or sub-select in the FROM clause of - ** this query, then it will not be possible to show that the DISTINCT - ** clause is redundant. */ - if( pTabList->nSrc!=1 ) return 0; - iBase = pTabList->a[0].iCursor; - pTab = pTabList->a[0].pTab; - - /* If any of the expressions is an IPK column on table iBase, then return - ** true. Note: The (p->iTable==iBase) part of this test may be false if the - ** current SELECT is a correlated sub-query. - */ - for(i=0; i<pDistinct->nExpr; i++){ - Expr *p = sqlite3ExprSkipCollate(pDistinct->a[i].pExpr); - if( p->op==TK_COLUMN && p->iTable==iBase && p->iColumn<0 ) return 1; - } - - /* Loop through all indices on the table, checking each to see if it makes - ** the DISTINCT qualifier redundant. It does so if: - ** - ** 1. The index is itself UNIQUE, and - ** - ** 2. All of the columns in the index are either part of the pDistinct - ** list, or else the WHERE clause contains a term of the form "col=X", - ** where X is a constant value. The collation sequences of the - ** comparison and select-list expressions must match those of the index. - ** - ** 3. All of those index columns for which the WHERE clause does not - ** contain a "col=X" term are subject to a NOT NULL constraint. - */ - for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){ - if( !IsUniqueIndex(pIdx) ) continue; - for(i=0; i<pIdx->nKeyCol; i++){ - if( 0==sqlite3WhereFindTerm(pWC, iBase, i, ~(Bitmask)0, WO_EQ, pIdx) ){ - if( findIndexCol(pParse, pDistinct, iBase, pIdx, i)<0 ) break; - if( indexColumnNotNull(pIdx, i)==0 ) break; - } - } - if( i==pIdx->nKeyCol ){ - /* This index implies that the DISTINCT qualifier is redundant. */ - return 1; - } - } - - return 0; -} - - -/* -** Estimate the logarithm of the input value to base 2. -*/ -static LogEst estLog(LogEst N){ - return N<=10 ? 0 : sqlite3LogEst(N) - 33; -} - -/* -** Convert OP_Column opcodes to OP_Copy in previously generated code. -** -** This routine runs over generated VDBE code and translates OP_Column -** opcodes into OP_Copy when the table is being accessed via co-routine -** instead of via table lookup. -** -** If the bIncrRowid parameter is 0, then any OP_Rowid instructions on -** cursor iTabCur are transformed into OP_Null. Or, if bIncrRowid is non-zero, -** then each OP_Rowid is transformed into an instruction to increment the -** value stored in its output register. -*/ -static void translateColumnToCopy( - Vdbe *v, /* The VDBE containing code to translate */ - int iStart, /* Translate from this opcode to the end */ - int iTabCur, /* OP_Column/OP_Rowid references to this table */ - int iRegister, /* The first column is in this register */ - int bIncrRowid /* If non-zero, transform OP_rowid to OP_AddImm(1) */ -){ - VdbeOp *pOp = sqlite3VdbeGetOp(v, iStart); - int iEnd = sqlite3VdbeCurrentAddr(v); - for(; iStart<iEnd; iStart++, pOp++){ - if( pOp->p1!=iTabCur ) continue; - if( pOp->opcode==OP_Column ){ - pOp->opcode = OP_Copy; - pOp->p1 = pOp->p2 + iRegister; - pOp->p2 = pOp->p3; - pOp->p3 = 0; - }else if( pOp->opcode==OP_Rowid ){ - if( bIncrRowid ){ - /* Increment the value stored in the P2 operand of the OP_Rowid. */ - pOp->opcode = OP_AddImm; - pOp->p1 = pOp->p2; - pOp->p2 = 1; - }else{ - pOp->opcode = OP_Null; - pOp->p1 = 0; - pOp->p3 = 0; - } - } - } -} - -/* -** Two routines for printing the content of an sqlite3_index_info -** structure. Used for testing and debugging only. If neither -** SQLITE_TEST or SQLITE_DEBUG are defined, then these routines -** are no-ops. -*/ -#if !defined(SQLITE_OMIT_VIRTUALTABLE) && defined(WHERETRACE_ENABLED) -static void TRACE_IDX_INPUTS(sqlite3_index_info *p){ - int i; - if( !sqlite3WhereTrace ) return; - for(i=0; i<p->nConstraint; i++){ - sqlite3DebugPrintf(" constraint[%d]: col=%d termid=%d op=%d usabled=%d\n", - i, - p->aConstraint[i].iColumn, - p->aConstraint[i].iTermOffset, - p->aConstraint[i].op, - p->aConstraint[i].usable); - } - for(i=0; i<p->nOrderBy; i++){ - sqlite3DebugPrintf(" orderby[%d]: col=%d desc=%d\n", - i, - p->aOrderBy[i].iColumn, - p->aOrderBy[i].desc); - } -} -static void TRACE_IDX_OUTPUTS(sqlite3_index_info *p){ - int i; - if( !sqlite3WhereTrace ) return; - for(i=0; i<p->nConstraint; i++){ - sqlite3DebugPrintf(" usage[%d]: argvIdx=%d omit=%d\n", - i, - p->aConstraintUsage[i].argvIndex, - p->aConstraintUsage[i].omit); - } - sqlite3DebugPrintf(" idxNum=%d\n", p->idxNum); - sqlite3DebugPrintf(" idxStr=%s\n", p->idxStr); - sqlite3DebugPrintf(" orderByConsumed=%d\n", p->orderByConsumed); - sqlite3DebugPrintf(" estimatedCost=%g\n", p->estimatedCost); - sqlite3DebugPrintf(" estimatedRows=%lld\n", p->estimatedRows); -} -#else -#define TRACE_IDX_INPUTS(A) -#define TRACE_IDX_OUTPUTS(A) -#endif - -#ifndef SQLITE_OMIT_AUTOMATIC_INDEX -/* -** Return TRUE if the WHERE clause term pTerm is of a form where it -** could be used with an index to access pSrc, assuming an appropriate -** index existed. -*/ -static int termCanDriveIndex( - WhereTerm *pTerm, /* WHERE clause term to check */ - struct SrcList_item *pSrc, /* Table we are trying to access */ - Bitmask notReady /* Tables in outer loops of the join */ -){ - char aff; - if( pTerm->leftCursor!=pSrc->iCursor ) return 0; - if( (pTerm->eOperator & (WO_EQ|WO_IS))==0 ) return 0; - if( (pTerm->prereqRight & notReady)!=0 ) return 0; - if( pTerm->u.leftColumn<0 ) return 0; - aff = pSrc->pTab->aCol[pTerm->u.leftColumn].affinity; - if( !sqlite3IndexAffinityOk(pTerm->pExpr, aff) ) return 0; - testcase( pTerm->pExpr->op==TK_IS ); - return 1; -} -#endif - - -#ifndef SQLITE_OMIT_AUTOMATIC_INDEX -/* -** Generate code to construct the Index object for an automatic index -** and to set up the WhereLevel object pLevel so that the code generator -** makes use of the automatic index. -*/ -static void constructAutomaticIndex( - Parse *pParse, /* The parsing context */ - WhereClause *pWC, /* The WHERE clause */ - struct SrcList_item *pSrc, /* The FROM clause term to get the next index */ - Bitmask notReady, /* Mask of cursors that are not available */ - WhereLevel *pLevel /* Write new index here */ -){ - int nKeyCol; /* Number of columns in the constructed index */ - WhereTerm *pTerm; /* A single term of the WHERE clause */ - WhereTerm *pWCEnd; /* End of pWC->a[] */ - Index *pIdx; /* Object describing the transient index */ - Vdbe *v; /* Prepared statement under construction */ - int addrInit; /* Address of the initialization bypass jump */ - Table *pTable; /* The table being indexed */ - int addrTop; /* Top of the index fill loop */ - int regRecord; /* Register holding an index record */ - int n; /* Column counter */ - int i; /* Loop counter */ - int mxBitCol; /* Maximum column in pSrc->colUsed */ - CollSeq *pColl; /* Collating sequence to on a column */ - WhereLoop *pLoop; /* The Loop object */ - char *zNotUsed; /* Extra space on the end of pIdx */ - 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 */ - struct SrcList_item *pTabItem; /* FROM clause term being indexed */ - int addrCounter; /* Address where integer counter is initialized */ - int regBase; /* Array of registers where record is assembled */ - - /* Generate code to skip over the creation and initialization of the - ** transient index on 2nd and subsequent iterations of the loop. */ - v = pParse->pVdbe; - assert( v!=0 ); - addrInit = sqlite3CodeOnce(pParse); VdbeCoverage(v); - - /* Count the number of columns that will be added to the index - ** and used to match WHERE clause constraints */ - nKeyCol = 0; - pTable = pSrc->pTab; - pWCEnd = &pWC->a[pWC->nTerm]; - pLoop = pLevel->pWLoop; - idxCols = 0; - for(pTerm=pWC->a; pTerm<pWCEnd; pTerm++){ - Expr *pExpr = pTerm->pExpr; - assert( !ExprHasProperty(pExpr, EP_FromJoin) /* prereq always non-zero */ - || pExpr->iRightJoinTable!=pSrc->iCursor /* for the right-hand */ - || pLoop->prereq!=0 ); /* table of a LEFT JOIN */ - if( pLoop->prereq==0 - && (pTerm->wtFlags & TERM_VIRTUAL)==0 - && !ExprHasProperty(pExpr, EP_FromJoin) - && sqlite3ExprIsTableConstant(pExpr, pSrc->iCursor) ){ - pPartial = sqlite3ExprAnd(pParse->db, pPartial, - sqlite3ExprDup(pParse->db, pExpr, 0)); - } - if( termCanDriveIndex(pTerm, pSrc, notReady) ){ - int iCol = pTerm->u.leftColumn; - Bitmask cMask = iCol>=BMS ? MASKBIT(BMS-1) : MASKBIT(iCol); - testcase( iCol==BMS ); - testcase( iCol==BMS-1 ); - if( !sentWarning ){ - sqlite3_log(SQLITE_WARNING_AUTOINDEX, - "automatic index on %s(%s)", pTable->zName, - pTable->aCol[iCol].zName); - sentWarning = 1; - } - if( (idxCols & cMask)==0 ){ - if( whereLoopResize(pParse->db, pLoop, nKeyCol+1) ){ - goto end_auto_index_create; - } - pLoop->aLTerm[nKeyCol++] = pTerm; - idxCols |= cMask; - } - } - } - assert( nKeyCol>0 ); - pLoop->u.btree.nEq = pLoop->nLTerm = nKeyCol; - pLoop->wsFlags = WHERE_COLUMN_EQ | WHERE_IDX_ONLY | WHERE_INDEXED - | WHERE_AUTO_INDEX; - - /* Count the number of additional columns needed to create a - ** covering index. A "covering index" is an index that contains all - ** columns that are needed by the query. With a covering index, the - ** original table never needs to be accessed. Automatic indices must - ** be a covering index because the index will not be updated if the - ** original table changes and the index and table cannot both be used - ** if they go out of sync. - */ - extraCols = pSrc->colUsed & (~idxCols | MASKBIT(BMS-1)); - mxBitCol = MIN(BMS-1,pTable->nCol); - testcase( pTable->nCol==BMS-1 ); - testcase( pTable->nCol==BMS-2 ); - for(i=0; i<mxBitCol; i++){ - if( extraCols & MASKBIT(i) ) nKeyCol++; - } - if( pSrc->colUsed & MASKBIT(BMS-1) ){ - nKeyCol += pTable->nCol - BMS + 1; - } - - /* Construct the Index object to describe this index */ - pIdx = sqlite3AllocateIndexObject(pParse->db, nKeyCol+1, 0, &zNotUsed); - if( pIdx==0 ) goto end_auto_index_create; - pLoop->u.btree.pIndex = pIdx; - pIdx->zName = "auto-index"; - pIdx->pTable = pTable; - n = 0; - idxCols = 0; - for(pTerm=pWC->a; pTerm<pWCEnd; pTerm++){ - if( termCanDriveIndex(pTerm, pSrc, notReady) ){ - int iCol = pTerm->u.leftColumn; - Bitmask cMask = iCol>=BMS ? MASKBIT(BMS-1) : MASKBIT(iCol); - testcase( iCol==BMS-1 ); - testcase( iCol==BMS ); - if( (idxCols & cMask)==0 ){ - Expr *pX = pTerm->pExpr; - idxCols |= cMask; - pIdx->aiColumn[n] = pTerm->u.leftColumn; - pColl = sqlite3BinaryCompareCollSeq(pParse, pX->pLeft, pX->pRight); - pIdx->azColl[n] = pColl ? pColl->zName : "BINARY"; - n++; - } - } - } - assert( (u32)n==pLoop->u.btree.nEq ); - - /* Add additional columns needed to make the automatic index into - ** a covering index */ - for(i=0; i<mxBitCol; i++){ - if( extraCols & MASKBIT(i) ){ - pIdx->aiColumn[n] = i; - pIdx->azColl[n] = "BINARY"; - n++; - } - } - if( pSrc->colUsed & MASKBIT(BMS-1) ){ - for(i=BMS-1; i<pTable->nCol; i++){ - pIdx->aiColumn[n] = i; - pIdx->azColl[n] = "BINARY"; - n++; - } - } - assert( n==nKeyCol ); - pIdx->aiColumn[n] = XN_ROWID; - pIdx->azColl[n] = "BINARY"; - - /* Create the automatic index */ - assert( pLevel->iIdxCur>=0 ); - pLevel->iIdxCur = pParse->nTab++; - sqlite3VdbeAddOp2(v, OP_OpenAutoindex, pLevel->iIdxCur, nKeyCol+1); - sqlite3VdbeSetP4KeyInfo(pParse, pIdx); - VdbeComment((v, "for %s", pTable->zName)); - - /* Fill the automatic index with content */ - sqlite3ExprCachePush(pParse); - pTabItem = &pWC->pWInfo->pTabList->a[pLevel->iFrom]; - if( pTabItem->fg.viaCoroutine ){ - int regYield = pTabItem->regReturn; - addrCounter = sqlite3VdbeAddOp2(v, OP_Integer, 0, 0); - sqlite3VdbeAddOp3(v, OP_InitCoroutine, regYield, 0, pTabItem->addrFillSub); - addrTop = sqlite3VdbeAddOp1(v, OP_Yield, regYield); - VdbeCoverage(v); - VdbeComment((v, "next row of \"%s\"", pTabItem->pTab->zName)); - }else{ - 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); - regBase = 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); - if( pTabItem->fg.viaCoroutine ){ - sqlite3VdbeChangeP2(v, addrCounter, regBase+n); - translateColumnToCopy(v, addrTop, pLevel->iTabCur, pTabItem->regResult, 1); - sqlite3VdbeGoto(v, addrTop); - pTabItem->fg.viaCoroutine = 0; - }else{ - 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 */ - -#ifndef SQLITE_OMIT_VIRTUALTABLE -/* -** Allocate and populate an sqlite3_index_info structure. It is the -** responsibility of the caller to eventually release the structure -** by passing the pointer returned by this function to sqlite3_free(). -*/ -static sqlite3_index_info *allocateIndexInfo( - Parse *pParse, - WhereClause *pWC, - Bitmask mUnusable, /* Ignore terms with these prereqs */ - struct SrcList_item *pSrc, - ExprList *pOrderBy -){ - int i, j; - int nTerm; - struct sqlite3_index_constraint *pIdxCons; - struct sqlite3_index_orderby *pIdxOrderBy; - struct sqlite3_index_constraint_usage *pUsage; - WhereTerm *pTerm; - int nOrderBy; - sqlite3_index_info *pIdxInfo; - - /* Count the number of possible WHERE clause constraints referring - ** to this virtual table */ - for(i=nTerm=0, pTerm=pWC->a; i<pWC->nTerm; i++, pTerm++){ - if( pTerm->leftCursor != pSrc->iCursor ) continue; - if( pTerm->prereqRight & mUnusable ) continue; - assert( IsPowerOfTwo(pTerm->eOperator & ~WO_EQUIV) ); - testcase( pTerm->eOperator & WO_IN ); - testcase( pTerm->eOperator & WO_ISNULL ); - testcase( pTerm->eOperator & WO_IS ); - testcase( pTerm->eOperator & WO_ALL ); - if( (pTerm->eOperator & ~(WO_ISNULL|WO_EQUIV|WO_IS))==0 ) continue; - if( pTerm->wtFlags & TERM_VNULL ) continue; - assert( pTerm->u.leftColumn>=(-1) ); - nTerm++; - } - - /* If the ORDER BY clause contains only columns in the current - ** virtual table then allocate space for the aOrderBy part of - ** the sqlite3_index_info structure. - */ - nOrderBy = 0; - if( pOrderBy ){ - int n = pOrderBy->nExpr; - for(i=0; i<n; i++){ - Expr *pExpr = pOrderBy->a[i].pExpr; - if( pExpr->op!=TK_COLUMN || pExpr->iTable!=pSrc->iCursor ) break; - } - if( i==n){ - nOrderBy = n; - } - } - - /* Allocate the sqlite3_index_info structure - */ - pIdxInfo = sqlite3DbMallocZero(pParse->db, sizeof(*pIdxInfo) - + (sizeof(*pIdxCons) + sizeof(*pUsage))*nTerm - + sizeof(*pIdxOrderBy)*nOrderBy ); - if( pIdxInfo==0 ){ - sqlite3ErrorMsg(pParse, "out of memory"); - return 0; - } - - /* Initialize the structure. The sqlite3_index_info structure contains - ** many fields that are declared "const" to prevent xBestIndex from - ** changing them. We have to do some funky casting in order to - ** initialize those fields. - */ - pIdxCons = (struct sqlite3_index_constraint*)&pIdxInfo[1]; - pIdxOrderBy = (struct sqlite3_index_orderby*)&pIdxCons[nTerm]; - pUsage = (struct sqlite3_index_constraint_usage*)&pIdxOrderBy[nOrderBy]; - *(int*)&pIdxInfo->nConstraint = nTerm; - *(int*)&pIdxInfo->nOrderBy = nOrderBy; - *(struct sqlite3_index_constraint**)&pIdxInfo->aConstraint = pIdxCons; - *(struct sqlite3_index_orderby**)&pIdxInfo->aOrderBy = pIdxOrderBy; - *(struct sqlite3_index_constraint_usage**)&pIdxInfo->aConstraintUsage = - pUsage; - - for(i=j=0, pTerm=pWC->a; i<pWC->nTerm; i++, pTerm++){ - u8 op; - if( pTerm->leftCursor != pSrc->iCursor ) continue; - if( pTerm->prereqRight & mUnusable ) continue; - assert( IsPowerOfTwo(pTerm->eOperator & ~WO_EQUIV) ); - testcase( pTerm->eOperator & WO_IN ); - testcase( pTerm->eOperator & WO_IS ); - testcase( pTerm->eOperator & WO_ISNULL ); - testcase( pTerm->eOperator & WO_ALL ); - if( (pTerm->eOperator & ~(WO_ISNULL|WO_EQUIV|WO_IS))==0 ) continue; - if( pTerm->wtFlags & TERM_VNULL ) continue; - assert( pTerm->u.leftColumn>=(-1) ); - pIdxCons[j].iColumn = pTerm->u.leftColumn; - pIdxCons[j].iTermOffset = i; - op = (u8)pTerm->eOperator & WO_ALL; - if( op==WO_IN ) op = WO_EQ; - pIdxCons[j].op = op; - /* The direct assignment in the previous line is possible only because - ** the WO_ and SQLITE_INDEX_CONSTRAINT_ codes are identical. The - ** following asserts verify this fact. */ - assert( WO_EQ==SQLITE_INDEX_CONSTRAINT_EQ ); - assert( WO_LT==SQLITE_INDEX_CONSTRAINT_LT ); - assert( WO_LE==SQLITE_INDEX_CONSTRAINT_LE ); - assert( WO_GT==SQLITE_INDEX_CONSTRAINT_GT ); - assert( WO_GE==SQLITE_INDEX_CONSTRAINT_GE ); - assert( WO_MATCH==SQLITE_INDEX_CONSTRAINT_MATCH ); - assert( pTerm->eOperator & (WO_IN|WO_EQ|WO_LT|WO_LE|WO_GT|WO_GE|WO_MATCH) ); - j++; - } - for(i=0; i<nOrderBy; i++){ - Expr *pExpr = pOrderBy->a[i].pExpr; - pIdxOrderBy[i].iColumn = pExpr->iColumn; - pIdxOrderBy[i].desc = pOrderBy->a[i].sortOrder; - } - - return pIdxInfo; -} - -/* -** The table object reference passed as the second argument to this function -** must represent a virtual table. This function invokes the xBestIndex() -** method of the virtual table with the sqlite3_index_info object that -** comes in as the 3rd argument to this function. -** -** If an error occurs, pParse is populated with an error message and a -** non-zero value is returned. Otherwise, 0 is returned and the output -** part of the sqlite3_index_info structure is left populated. -** -** Whether or not an error is returned, it is the responsibility of the -** caller to eventually free p->idxStr if p->needToFreeIdxStr indicates -** that this is required. -*/ -static int vtabBestIndex(Parse *pParse, Table *pTab, sqlite3_index_info *p){ - sqlite3_vtab *pVtab = sqlite3GetVTable(pParse->db, pTab)->pVtab; - int i; - int rc; - - TRACE_IDX_INPUTS(p); - rc = pVtab->pModule->xBestIndex(pVtab, p); - TRACE_IDX_OUTPUTS(p); - - if( rc!=SQLITE_OK ){ - if( rc==SQLITE_NOMEM ){ - pParse->db->mallocFailed = 1; - }else if( !pVtab->zErrMsg ){ - sqlite3ErrorMsg(pParse, "%s", sqlite3ErrStr(rc)); - }else{ - sqlite3ErrorMsg(pParse, "%s", pVtab->zErrMsg); - } - } - sqlite3_free(pVtab->zErrMsg); - pVtab->zErrMsg = 0; - - for(i=0; i<p->nConstraint; i++){ - if( !p->aConstraint[i].usable && p->aConstraintUsage[i].argvIndex>0 ){ - sqlite3ErrorMsg(pParse, - "table %s: xBestIndex returned an invalid plan", pTab->zName); - } - } - - return pParse->nErr; -} -#endif /* !defined(SQLITE_OMIT_VIRTUALTABLE) */ - -#ifdef SQLITE_ENABLE_STAT3_OR_STAT4 -/* -** Estimate the location of a particular key among all keys in an -** index. Store the results in aStat as follows: -** -** aStat[0] Est. number of rows less than pRec -** aStat[1] Est. number of rows equal to pRec -** -** Return the index of the sample that is the smallest sample that -** is greater than or equal to pRec. Note that this index is not an index -** into the aSample[] array - it is an index into a virtual set of samples -** based on the contents of aSample[] and the number of fields in record -** pRec. -*/ -static int whereKeyStats( - Parse *pParse, /* Database connection */ - Index *pIdx, /* Index to consider domain of */ - UnpackedRecord *pRec, /* Vector of values to consider */ - int roundUp, /* Round up if true. Round down if false */ - tRowcnt *aStat /* OUT: stats written here */ -){ - IndexSample *aSample = pIdx->aSample; - int iCol; /* Index of required stats in anEq[] etc. */ - int i; /* Index of first sample >= pRec */ - int iSample; /* Smallest sample larger than or equal to pRec */ - int iMin = 0; /* Smallest sample not yet tested */ - int iTest; /* Next sample to test */ - int res; /* Result of comparison operation */ - int nField; /* Number of fields in pRec */ - tRowcnt iLower = 0; /* anLt[] + anEq[] of largest sample pRec is > */ - -#ifndef SQLITE_DEBUG - UNUSED_PARAMETER( pParse ); -#endif - assert( pRec!=0 ); - assert( pIdx->nSample>0 ); - assert( pRec->nField>0 && pRec->nField<=pIdx->nSampleCol ); - - /* Do a binary search to find the first sample greater than or equal - ** to pRec. If pRec contains a single field, the set of samples to search - ** is simply the aSample[] array. If the samples in aSample[] contain more - ** than one fields, all fields following the first are ignored. - ** - ** If pRec contains N fields, where N is more than one, then as well as the - ** samples in aSample[] (truncated to N fields), the search also has to - ** consider prefixes of those samples. For example, if the set of samples - ** in aSample is: - ** - ** aSample[0] = (a, 5) - ** aSample[1] = (a, 10) - ** aSample[2] = (b, 5) - ** aSample[3] = (c, 100) - ** aSample[4] = (c, 105) - ** - ** Then the search space should ideally be the samples above and the - ** unique prefixes [a], [b] and [c]. But since that is hard to organize, - ** the code actually searches this set: - ** - ** 0: (a) - ** 1: (a, 5) - ** 2: (a, 10) - ** 3: (a, 10) - ** 4: (b) - ** 5: (b, 5) - ** 6: (c) - ** 7: (c, 100) - ** 8: (c, 105) - ** 9: (c, 105) - ** - ** For each sample in the aSample[] array, N samples are present in the - ** effective sample array. In the above, samples 0 and 1 are based on - ** sample aSample[0]. Samples 2 and 3 on aSample[1] etc. - ** - ** Often, sample i of each block of N effective samples has (i+1) fields. - ** Except, each sample may be extended to ensure that it is greater than or - ** equal to the previous sample in the array. For example, in the above, - ** sample 2 is the first sample of a block of N samples, so at first it - ** appears that it should be 1 field in size. However, that would make it - ** smaller than sample 1, so the binary search would not work. As a result, - ** it is extended to two fields. The duplicates that this creates do not - ** cause any problems. - */ - nField = pRec->nField; - iCol = 0; - iSample = pIdx->nSample * nField; - do{ - int iSamp; /* Index in aSample[] of test sample */ - int n; /* Number of fields in test sample */ - - iTest = (iMin+iSample)/2; - iSamp = iTest / nField; - if( iSamp>0 ){ - /* The proposed effective sample is a prefix of sample aSample[iSamp]. - ** Specifically, the shortest prefix of at least (1 + iTest%nField) - ** fields that is greater than the previous effective sample. */ - for(n=(iTest % nField) + 1; n<nField; n++){ - if( aSample[iSamp-1].anLt[n-1]!=aSample[iSamp].anLt[n-1] ) break; - } - }else{ - n = iTest + 1; - } - - pRec->nField = n; - res = sqlite3VdbeRecordCompare(aSample[iSamp].n, aSample[iSamp].p, pRec); - if( res<0 ){ - iLower = aSample[iSamp].anLt[n-1] + aSample[iSamp].anEq[n-1]; - iMin = iTest+1; - }else if( res==0 && n<nField ){ - iLower = aSample[iSamp].anLt[n-1]; - iMin = iTest+1; - res = -1; - }else{ - iSample = iTest; - iCol = n-1; - } - }while( res && iMin<iSample ); - i = iSample / nField; - -#ifdef SQLITE_DEBUG - /* The following assert statements check that the binary search code - ** above found the right answer. This block serves no purpose other - ** than to invoke the asserts. */ - if( pParse->db->mallocFailed==0 ){ - if( res==0 ){ - /* If (res==0) is true, then pRec must be equal to sample i. */ - assert( i<pIdx->nSample ); - assert( iCol==nField-1 ); - pRec->nField = nField; - assert( 0==sqlite3VdbeRecordCompare(aSample[i].n, aSample[i].p, pRec) - || pParse->db->mallocFailed - ); - }else{ - /* Unless i==pIdx->nSample, indicating that pRec is larger than - ** all samples in the aSample[] array, pRec must be smaller than the - ** (iCol+1) field prefix of sample i. */ - assert( i<=pIdx->nSample && i>=0 ); - pRec->nField = iCol+1; - assert( i==pIdx->nSample - || sqlite3VdbeRecordCompare(aSample[i].n, aSample[i].p, pRec)>0 - || pParse->db->mallocFailed ); - - /* if i==0 and iCol==0, then record pRec is smaller than all samples - ** in the aSample[] array. Otherwise, if (iCol>0) then pRec must - ** be greater than or equal to the (iCol) field prefix of sample i. - ** If (i>0), then pRec must also be greater than sample (i-1). */ - if( iCol>0 ){ - pRec->nField = iCol; - assert( sqlite3VdbeRecordCompare(aSample[i].n, aSample[i].p, pRec)<=0 - || pParse->db->mallocFailed ); - } - if( i>0 ){ - pRec->nField = nField; - assert( sqlite3VdbeRecordCompare(aSample[i-1].n, aSample[i-1].p, pRec)<0 - || pParse->db->mallocFailed ); - } - } - } -#endif /* ifdef SQLITE_DEBUG */ - - if( res==0 ){ - /* Record pRec is equal to sample i */ - assert( iCol==nField-1 ); - aStat[0] = aSample[i].anLt[iCol]; - aStat[1] = aSample[i].anEq[iCol]; - }else{ - /* At this point, the (iCol+1) field prefix of aSample[i] is the first - ** sample that is greater than pRec. Or, if i==pIdx->nSample then pRec - ** is larger than all samples in the array. */ - tRowcnt iUpper, iGap; - if( i>=pIdx->nSample ){ - iUpper = sqlite3LogEstToInt(pIdx->aiRowLogEst[0]); - }else{ - iUpper = aSample[i].anLt[iCol]; - } - - if( iLower>=iUpper ){ - iGap = 0; - }else{ - iGap = iUpper - iLower; - } - if( roundUp ){ - iGap = (iGap*2)/3; - }else{ - iGap = iGap/3; - } - aStat[0] = iLower + iGap; - aStat[1] = pIdx->aAvgEq[iCol]; - } - - /* Restore the pRec->nField value before returning. */ - pRec->nField = nField; - return i; -} -#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 -/* -** Return the affinity for a single column of an index. -*/ -static char sqlite3IndexColumnAffinity(sqlite3 *db, Index *pIdx, int iCol){ - assert( iCol>=0 && iCol<pIdx->nColumn ); - if( !pIdx->zColAff ){ - if( sqlite3IndexAffinityStr(db, pIdx)==0 ) return SQLITE_AFF_BLOB; - } - return pIdx->zColAff[iCol]; -} -#endif - - -#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; - u8 aff = sqlite3IndexColumnAffinity(db, p, nEq); - 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 -** and lower bounds are represented by pLower and pUpper respectively. For -** example, assuming that index p is on t1(a): -** -** ... FROM t1 WHERE a > ? AND a < ? ... -** |_____| |_____| -** | | -** pLower pUpper -** -** 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 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: -** -** ... FROM t1 WHERE a = ? AND b > ? AND b < ? ... -** -** then nEq is set to 1 (as the range restricted column, b, is the second -** left-most column of the index). Or, if the query is: -** -** ... FROM t1 WHERE a > ? AND a < ? ... -** -** then nEq is set to 0. -** -** 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, then *pnOut is the number of -** rows in the index. Assuming no error occurs, *pnOut is adjusted (reduced) -** 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. -** 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 */ - WhereLoopBuilder *pBuilder, - 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 /* Modify the .nOut and maybe .rRun fields */ -){ - int rc = SQLITE_OK; - int nOut = pLoop->nOut; - LogEst nNew; - -#ifdef SQLITE_ENABLE_STAT3_OR_STAT4 - Index *p = pLoop->u.btree.pIndex; - int nEq = pLoop->u.btree.nEq; - - 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 $U is available, both values - ** of iUpper are requested of whereKeyStats() and the smaller used. - ** - ** The number of rows between the two bounds is then just iUpper-iLower. - */ - tRowcnt iLower; /* Rows less than the lower bound */ - tRowcnt iUpper; /* Rows less than the upper bound */ - int iLwrIdx = -2; /* aSample[] for the lower bound */ - int iUprIdx = -1; /* aSample[] for the upper bound */ - - if( pRec ){ - testcase( pRec->nField!=pBuilder->nRecValid ); - pRec->nField = pBuilder->nRecValid; - } - aff = sqlite3IndexColumnAffinity(pParse->db, p, nEq); - assert( nEq!=p->nKeyCol || aff==SQLITE_AFF_INTEGER ); - /* Determine iLower and iUpper using ($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 $P in whereEqualScanEst(). */ - whereKeyStats(pParse, p, pRec, 0, a); - iLower = a[0]; - iUpper = a[0] + a[1]; - } - - assert( pLower==0 || (pLower->eOperator & (WO_GT|WO_GE))!=0 ); - assert( pUpper==0 || (pUpper->eOperator & (WO_LT|WO_LE))!=0 ); - assert( p->aSortOrder!=0 ); - if( p->aSortOrder[nEq] ){ - /* The roles of pLower and pUpper are swapped for a DESC index */ - SWAP(WhereTerm*, pLower, pUpper); - } - - /* If possible, improve on the iLower estimate using ($P:$L). */ - if( pLower ){ - int bOk; /* True if value is extracted from pExpr */ - Expr *pExpr = pLower->pExpr->pRight; - rc = sqlite3Stat4ProbeSetValue(pParse, p, &pRec, pExpr, aff, nEq, &bOk); - if( rc==SQLITE_OK && bOk ){ - tRowcnt iNew; - iLwrIdx = whereKeyStats(pParse, p, pRec, 0, a); - iNew = a[0] + ((pLower->eOperator & (WO_GT|WO_LE)) ? a[1] : 0); - if( iNew>iLower ) iLower = iNew; - nOut--; - pLower = 0; - } - } - - /* If possible, improve on the iUpper estimate using ($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; - } - } - - 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); - 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 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 && 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; -} - -#ifdef SQLITE_ENABLE_STAT3_OR_STAT4 -/* -** Estimate the number of rows that will be returned based on -** an equality constraint x=VALUE and where that VALUE occurs in -** the histogram data. This only works when x is the left-most -** column of an index and sqlite_stat3 histogram data is available -** for that index. When pExpr==NULL that means the constraint is -** "x IS NULL" instead of "x=VALUE". -** -** Write the estimated row count into *pnRow and return SQLITE_OK. -** If unable to make an estimate, leave *pnRow unchanged and return -** non-zero. -** -** This routine can fail if it is unable to load a collating sequence -** required for string comparison, or if unable to allocate memory -** for a UTF conversion required for comparison. The error is stored -** in the pParse structure. -*/ -static int whereEqualScanEst( - Parse *pParse, /* Parsing & code generating context */ - WhereLoopBuilder *pBuilder, - Expr *pExpr, /* Expression for VALUE in the x=VALUE constraint */ - tRowcnt *pnRow /* Write the revised row estimate here */ -){ - Index *p = pBuilder->pNew->u.btree.pIndex; - int nEq = pBuilder->pNew->u.btree.nEq; - UnpackedRecord *pRec = pBuilder->pRec; - u8 aff; /* Column affinity */ - int rc; /* Subfunction return code */ - tRowcnt a[2]; /* Statistics */ - int bOk; - - assert( nEq>=1 ); - assert( nEq<=p->nColumn ); - assert( p->aSample!=0 ); - assert( p->nSample>0 ); - assert( pBuilder->nRecValid<nEq ); - - /* If values are not available for all fields of the index to the left - ** of this one, no estimate can be made. Return SQLITE_NOTFOUND. */ - if( pBuilder->nRecValid<(nEq-1) ){ - return SQLITE_NOTFOUND; - } - - /* This is an optimization only. The call to sqlite3Stat4ProbeSetValue() - ** below would return the same value. */ - if( nEq>=p->nColumn ){ - *pnRow = 1; - return SQLITE_OK; - } - - aff = sqlite3IndexColumnAffinity(pParse->db, p, nEq-1); - rc = sqlite3Stat4ProbeSetValue(pParse, p, &pRec, pExpr, aff, nEq-1, &bOk); - pBuilder->pRec = pRec; - if( rc!=SQLITE_OK ) return rc; - if( bOk==0 ) return SQLITE_NOTFOUND; - pBuilder->nRecValid = nEq; - - whereKeyStats(pParse, p, pRec, 0, a); - WHERETRACE(0x10,("equality scan regions: %d\n", (int)a[1])); - *pnRow = a[1]; - - return rc; -} -#endif /* SQLITE_ENABLE_STAT3_OR_STAT4 */ - -#ifdef SQLITE_ENABLE_STAT3_OR_STAT4 -/* -** Estimate the number of rows that will be returned based on -** an IN constraint where the right-hand side of the IN operator -** is a list of values. Example: -** -** WHERE x IN (1,2,3,4) -** -** Write the estimated row count into *pnRow and return SQLITE_OK. -** If unable to make an estimate, leave *pnRow unchanged and return -** non-zero. -** -** This routine can fail if it is unable to load a collating sequence -** required for string comparison, or if unable to allocate memory -** for a UTF conversion required for comparison. The error is stored -** in the pParse structure. -*/ -static int whereInScanEst( - Parse *pParse, /* Parsing & code generating context */ - WhereLoopBuilder *pBuilder, - ExprList *pList, /* The value list on the RHS of "x IN (v1,v2,v3,...)" */ - 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 */ - tRowcnt nRowEst = 0; /* New estimate of the number of rows */ - int i; /* Loop counter */ - - assert( p->aSample!=0 ); - for(i=0; rc==SQLITE_OK && i<pList->nExpr; i++){ - nEst = nRow0; - rc = whereEqualScanEst(pParse, pBuilder, pList->a[i].pExpr, &nEst); - nRowEst += nEst; - pBuilder->nRecValid = nRecValid; - } - - if( rc==SQLITE_OK ){ - if( nRowEst > nRow0 ) nRowEst = nRow0; - *pnRow = nRowEst; - WHERETRACE(0x10,("IN row estimate: est=%d\n", nRowEst)); - } - assert( pBuilder->nRecValid==nRecValid ); - return rc; -} -#endif /* SQLITE_ENABLE_STAT3_OR_STAT4 */ - - -#ifdef WHERETRACE_ENABLED -/* -** Print the content of a WhereTerm object -*/ -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 wtFlags=0x%04x\n", - iTerm, pTerm, zType, pTerm->leftCursor, pTerm->truthProb, - pTerm->eOperator, pTerm->wtFlags); - sqlite3TreeViewExpr(0, pTerm->pExpr, 0); - } -} -#endif - -#ifdef WHERETRACE_ENABLED -/* -** Print a WhereLoop object for debugging purposes -*/ -static void whereLoopPrint(WhereLoop *p, WhereClause *pWC){ - WhereInfo *pWInfo = pWC->pWInfo; - int nb = 1+(pWInfo->pTabList->nSrc+7)/8; - struct SrcList_item *pItem = pWInfo->pTabList->a + p->iTab; - Table *pTab = pItem->pTab; - sqlite3DebugPrintf("%c%2d.%0*llx.%0*llx", p->cId, - p->iTab, nb, p->maskSelf, nb, p->prereq); - 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 ){ - if( strncmp(zName, "sqlite_autoindex_", 17)==0 ){ - int i = sqlite3Strlen30(zName) - 1; - while( zName[i]!='_' ) i--; - zName += i; - } - sqlite3DebugPrintf(".%-16s %2d", zName, p->u.btree.nEq); - }else{ - sqlite3DebugPrintf("%20s",""); - } - }else{ - char *z; - if( p->u.vtab.idxStr ){ - z = sqlite3_mprintf("(%d,\"%s\",%x)", - p->u.vtab.idxNum, p->u.vtab.idxStr, p->u.vtab.omitMask); - }else{ - z = sqlite3_mprintf("(%d,%x)", p->u.vtab.idxNum, p->u.vtab.omitMask); - } - sqlite3DebugPrintf(" %-19s", z); - sqlite3_free(z); - } - 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); - if( p->nLTerm && (sqlite3WhereTrace & 0x100)!=0 ){ - int i; - for(i=0; i<p->nLTerm; i++){ - whereTermPrint(p->aLTerm[i], i); - } - } -} -#endif - -/* -** Convert bulk memory into a valid WhereLoop that can be passed -** to whereLoopClear harmlessly. -*/ -static void whereLoopInit(WhereLoop *p){ - p->aLTerm = p->aLTermSpace; - p->nLTerm = 0; - p->nLSlot = ArraySize(p->aLTermSpace); - p->wsFlags = 0; -} - -/* -** Clear the WhereLoop.u union. Leave WhereLoop.pLTerm intact. -*/ -static void whereLoopClearUnion(sqlite3 *db, WhereLoop *p){ - if( p->wsFlags & (WHERE_VIRTUALTABLE|WHERE_AUTO_INDEX) ){ - if( (p->wsFlags & WHERE_VIRTUALTABLE)!=0 && p->u.vtab.needFree ){ - sqlite3_free(p->u.vtab.idxStr); - p->u.vtab.needFree = 0; - 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); - sqlite3DbFree(db, p->u.btree.pIndex); - p->u.btree.pIndex = 0; - } - } -} - -/* -** Deallocate internal memory used by a WhereLoop object -*/ -static void whereLoopClear(sqlite3 *db, WhereLoop *p){ - if( p->aLTerm!=p->aLTermSpace ) sqlite3DbFree(db, p->aLTerm); - whereLoopClearUnion(db, p); - whereLoopInit(p); -} - -/* -** Increase the memory allocation for pLoop->aLTerm[] to be at least n. -*/ -static int whereLoopResize(sqlite3 *db, WhereLoop *p, int n){ - WhereTerm **paNew; - if( p->nLSlot>=n ) return SQLITE_OK; - n = (n+7)&~7; - paNew = sqlite3DbMallocRaw(db, sizeof(p->aLTerm[0])*n); - if( paNew==0 ) return SQLITE_NOMEM; - memcpy(paNew, p->aLTerm, sizeof(p->aLTerm[0])*p->nLSlot); - if( p->aLTerm!=p->aLTermSpace ) sqlite3DbFree(db, p->aLTerm); - p->aLTerm = paNew; - p->nLSlot = n; - return SQLITE_OK; -} - -/* -** Transfer content from the second pLoop into the first. -*/ -static int whereLoopXfer(sqlite3 *db, WhereLoop *pTo, WhereLoop *pFrom){ - whereLoopClearUnion(db, pTo); - if( whereLoopResize(db, pTo, pFrom->nLTerm) ){ - memset(&pTo->u, 0, sizeof(pTo->u)); - return SQLITE_NOMEM; - } - memcpy(pTo, pFrom, WHERE_LOOP_XFER_SZ); - memcpy(pTo->aLTerm, pFrom->aLTerm, pTo->nLTerm*sizeof(pTo->aLTerm[0])); - if( pFrom->wsFlags & WHERE_VIRTUALTABLE ){ - pFrom->u.vtab.needFree = 0; - }else if( (pFrom->wsFlags & WHERE_AUTO_INDEX)!=0 ){ - pFrom->u.btree.pIndex = 0; - } - return SQLITE_OK; -} - -/* -** Delete a WhereLoop object -*/ -static void whereLoopDelete(sqlite3 *db, WhereLoop *p){ - whereLoopClear(db, p); - sqlite3DbFree(db, p); -} - -/* -** Free a WhereInfo structure -*/ -static void whereInfoFree(sqlite3 *db, WhereInfo *pWInfo){ - if( ALWAYS(pWInfo) ){ - int i; - for(i=0; i<pWInfo->nLevel; i++){ - WhereLevel *pLevel = &pWInfo->a[i]; - if( pLevel->pWLoop && (pLevel->pWLoop->wsFlags & WHERE_IN_ABLE) ){ - sqlite3DbFree(db, pLevel->u.in.aInLoop); - } - } - sqlite3WhereClauseClear(&pWInfo->sWC); - while( pWInfo->pLoops ){ - WhereLoop *p = pWInfo->pLoops; - pWInfo->pLoops = p->pNextLoop; - whereLoopDelete(db, p); - } - sqlite3DbFree(db, pWInfo); - } -} - -/* -** 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 -** 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. 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-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; - } - 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. -*/ -static void whereLoopAdjustCost(const WhereLoop *p, WhereLoop *pTemplate){ - if( (pTemplate->wsFlags & WHERE_INDEXED)==0 ) return; - for(; p; p=p->pNextLoop){ - if( p->iTab!=pTemplate->iTab ) continue; - if( (p->wsFlags & WHERE_INDEXED)==0 ) continue; - if( whereLoopCheaperProperSubset(p, pTemplate) ){ - /* Adjust pTemplate cost downward so that it is cheaper than its - ** subset p. */ - WHERETRACE(0x80,("subset cost adjustment %d,%d to %d,%d\n", - pTemplate->rRun, pTemplate->nOut, p->rRun, p->nOut-1)); - pTemplate->rRun = p->rRun; - pTemplate->nOut = p->nOut - 1; - }else if( whereLoopCheaperProperSubset(pTemplate, p) ){ - /* Adjust pTemplate cost upward so that it is costlier than p since - ** pTemplate is a proper subset of p */ - WHERETRACE(0x80,("subset cost adjustment %d,%d to %d,%d\n", - pTemplate->rRun, pTemplate->nOut, p->rRun, p->nOut+1)); - pTemplate->rRun = p->rRun; - pTemplate->nOut = p->nOut + 1; - } - } -} - -/* -** 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. 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 - ){ - 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 -** is better and has fewer dependencies. Or the template will be ignored -** and no insert will occur if an existing WhereLoop is faster and has -** fewer dependencies than the template. Otherwise a new WhereLoop is -** added based on the template. -** -** 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 -** 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 -*/ -static int whereLoopInsert(WhereLoopBuilder *pBuilder, WhereLoop *pTemplate){ - WhereLoop **ppPrev, *p; - WhereInfo *pWInfo = pBuilder->pWInfo; - sqlite3 *db = pWInfo->pParse->db; - - /* If pBuilder->pOrSet is defined, then only keep track of the costs - ** and prereqs. - */ - if( pBuilder->pOrSet!=0 ){ - if( pTemplate->nLTerm ){ -#if WHERETRACE_ENABLED - u16 n = pBuilder->pOrSet->n; - int x = -#endif - whereOrInsert(pBuilder->pOrSet, pTemplate->prereq, pTemplate->rRun, - pTemplate->nOut); -#if WHERETRACE_ENABLED /* 0x8 */ - if( sqlite3WhereTrace & 0x8 ){ - sqlite3DebugPrintf(x?" or-%d: ":" or-X: ", n); - whereLoopPrint(pTemplate, pBuilder->pWC); - } -#endif - } - return SQLITE_OK; - } - - /* Look for an existing WhereLoop to replace with pTemplate - */ - whereLoopAdjustCost(pWInfo->pLoops, pTemplate); - ppPrev = whereLoopFindLesser(&pWInfo->pLoops, pTemplate); - - 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(" skip: "); - whereLoopPrint(pTemplate, pBuilder->pWC); - } -#endif - return SQLITE_OK; - }else{ - p = *ppPrev; - } - - /* If we reach this point it means that either p[] should be overwritten - ** with pTemplate[] if p[] exists, or if p==NULL then allocate a new - ** WhereLoop and insert it. - */ -#if WHERETRACE_ENABLED /* 0x8 */ - if( sqlite3WhereTrace & 0x8 ){ - if( p!=0 ){ - sqlite3DebugPrintf("replace: "); - whereLoopPrint(p, pBuilder->pWC); - } - sqlite3DebugPrintf(" add: "); - whereLoopPrint(pTemplate, pBuilder->pWC); - } -#endif - if( p==0 ){ - /* 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(" delete: "); - whereLoopPrint(pToDel, pBuilder->pWC); - } -#endif - whereLoopDelete(db, pToDel); - } - } - whereLoopXfer(db, p, pTemplate); - if( (p->wsFlags & WHERE_VIRTUALTABLE)==0 ){ - Index *pIndex = p->u.btree.pIndex; - if( pIndex && pIndex->tnum==0 ){ - p->u.btree.pIndex = 0; - } - } - return SQLITE_OK; -} - -/* -** 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. -* -** 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, /* 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, k; - LogEst iReduce = 0; /* pLoop->nOut should not exceed nRow-iReduce */ - - 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; - if( (pTerm->prereqAll & notAllowed)!=0 ) continue; - for(j=pLoop->nLTerm-1; j>=0; j--){ - pX = pLoop->aLTerm[j]; - if( pX==0 ) continue; - if( pX==pTerm ) break; - if( pX->iParent>=0 && (&pWC->a[pX->iParent])==pTerm ) break; - } - if( j<0 ){ - 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|WO_IS) ){ - Expr *pRight = pTerm->pExpr->pRight; - testcase( pTerm->pExpr->op==TK_IS ); - 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. -** -** 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. -*/ -static int whereLoopAddBtreeIndex( - WhereLoopBuilder *pBuilder, /* The WhereLoop factory */ - struct SrcList_item *pSrc, /* FROM clause term being analyzed */ - Index *pProbe, /* An index on pSrc */ - LogEst nInMul /* log(Number of iterations due to IN) */ -){ - WhereInfo *pWInfo = pBuilder->pWInfo; /* WHERE analyse context */ - Parse *pParse = pWInfo->pParse; /* Parsing context */ - sqlite3 *db = pParse->db; /* Database connection malloc context */ - WhereLoop *pNew; /* Template WhereLoop under construction */ - WhereTerm *pTerm; /* A WhereTerm under consideration */ - int opMask; /* Valid operators for constraints */ - WhereScan scan; /* Iterator for WHERE terms */ - 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->nSkip */ - u32 saved_wsFlags; /* Original value of pNew->wsFlags */ - LogEst saved_nOut; /* Original value of pNew->nOut */ - 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 */ - - pNew = pBuilder->pNew; - if( db->mallocFailed ) return SQLITE_NOMEM; - - assert( (pNew->wsFlags & WHERE_VIRTUALTABLE)==0 ); - assert( (pNew->wsFlags & WHERE_TOP_LIMIT)==0 ); - if( pNew->wsFlags & WHERE_BTM_LIMIT ){ - opMask = WO_LT|WO_LE; - }else if( /*pProbe->tnum<=0 ||*/ (pSrc->fg.jointype & JT_LEFT)!=0 ){ - opMask = WO_EQ|WO_IN|WO_GT|WO_GE|WO_LT|WO_LE; - }else{ - opMask = WO_EQ|WO_IN|WO_GT|WO_GE|WO_LT|WO_LE|WO_ISNULL|WO_IS; - } - if( pProbe->bUnordered ) opMask &= ~(WO_GT|WO_GE|WO_LT|WO_LE); - - assert( pNew->u.btree.nEq<pProbe->nColumn ); - - saved_nEq = pNew->u.btree.nEq; - saved_nSkip = pNew->nSkip; - saved_nLTerm = pNew->nLTerm; - saved_wsFlags = pNew->wsFlags; - saved_prereq = pNew->prereq; - saved_nOut = pNew->nOut; - pTerm = whereScanInit(&scan, pBuilder->pWC, pSrc->iCursor, saved_nEq, - opMask, pProbe); - pNew->rSetup = 0; - 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; - LogEst nOutUnadjusted; /* nOut before IN() and WHERE adjustments */ - int nIn = 0; -#ifdef SQLITE_ENABLE_STAT3_OR_STAT4 - int nRecValid = pBuilder->nRecValid; -#endif - if( (eOp==WO_ISNULL || (pTerm->wtFlags&TERM_VNULL)!=0) - && indexColumnNotNull(pProbe, saved_nEq) - ){ - continue; /* ignore IS [NOT] NULL constraints on NOT NULL columns */ - } - if( pTerm->prereqRight & pNew->maskSelf ) continue; - - /* Do not allow the upper bound of a LIKE optimization range constraint - ** to mix with a lower range bound from some other source */ - if( pTerm->wtFlags & TERM_LIKEOPT && pTerm->eOperator==WO_LT ) continue; - - 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; - - 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) ){ - /* "x IN (SELECT ...)": TUNING: the SELECT returns 25 rows */ - nIn = 46; assert( 46==sqlite3LogEst(25) ); - }else if( ALWAYS(pExpr->x.pList && pExpr->x.pList->nExpr) ){ - /* "x IN (value, value, ...)" */ - nIn = sqlite3LogEst(pExpr->x.pList->nExpr); - } - assert( nIn>0 ); /* RHS always has 2 or more terms... The parser - ** changes "x IN (?)" into "x=?". */ - - }else if( eOp & (WO_EQ|WO_IS) ){ - int iCol = pProbe->aiColumn[saved_nEq]; - pNew->wsFlags |= WHERE_COLUMN_EQ; - assert( saved_nEq==pNew->u.btree.nEq ); - if( iCol==XN_ROWID - || (iCol>0 && nInMul==0 && saved_nEq==pProbe->nKeyCol-1) - ){ - if( iCol>=0 && pProbe->uniqNotNull==0 ){ - pNew->wsFlags |= WHERE_UNQ_WANTED; - }else{ - pNew->wsFlags |= WHERE_ONEROW; - } - } - }else if( eOp & WO_ISNULL ){ - pNew->wsFlags |= WHERE_COLUMN_NULL; - }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; - if( pTerm->wtFlags & TERM_LIKEOPT ){ - /* Range contraints that come from the LIKE optimization are - ** always used in pairs. */ - pTop = &pTerm[1]; - assert( (pTop-(pTerm->pWC->a))<pTerm->pWC->nTerm ); - assert( pTop->wtFlags & TERM_LIKEOPT ); - assert( pTop->eOperator==WO_LT ); - if( whereLoopResize(db, pNew, pNew->nLTerm+1) ) break; /* OOM */ - pNew->aLTerm[pNew->nLTerm++] = pTop; - pNew->wsFlags |= WHERE_TOP_LIMIT; - } - }else{ - 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 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|WO_IS) ); - - assert( pNew->nOut==saved_nOut ); - if( pTerm->truthProb<=0 && pProbe->aiColumn[saved_nEq]>=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 - tRowcnt nOut = 0; - if( nInMul==0 - && pProbe->nSample - && pNew->u.btree.nEq<=pProbe->nSampleCol - && ((eOp & WO_IN)==0 || !ExprHasProperty(pTerm->pExpr, EP_xIsSelect)) - ){ - Expr *pExpr = pTerm->pExpr; - if( (eOp & (WO_EQ|WO_ISNULL|WO_IS))!=0 ){ - testcase( eOp & WO_EQ ); - testcase( eOp & WO_IS ); - 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; - } - } - } - } - - /* 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 ){ - 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, rSize); - 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->nColumn - ){ - whereLoopAddBtreeIndex(pBuilder, pSrc, pProbe, nInMul+nIn); - } - pNew->nOut = saved_nOut; -#ifdef SQLITE_ENABLE_STAT3_OR_STAT4 - pBuilder->nRecValid = nRecValid; -#endif - } - pNew->prereq = saved_prereq; - pNew->u.btree.nEq = saved_nEq; - 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; -} - -/* -** Return True if it is possible that pIndex might be useful in -** implementing the ORDER BY clause in pBuilder. -** -** Return False if pBuilder does not contain an ORDER BY clause or -** if there is no way for pIndex to be useful in implementing that -** ORDER BY clause. -*/ -static int indexMightHelpWithOrderBy( - WhereLoopBuilder *pBuilder, - Index *pIndex, - int iCursor -){ - ExprList *pOB; - ExprList *aColExpr; - int ii, jj; - - if( pIndex->bUnordered ) return 0; - if( (pOB = pBuilder->pWInfo->pOrderBy)==0 ) return 0; - for(ii=0; ii<pOB->nExpr; ii++){ - Expr *pExpr = sqlite3ExprSkipCollate(pOB->a[ii].pExpr); - if( pExpr->op==TK_COLUMN && pExpr->iTable==iCursor ){ - if( pExpr->iColumn<0 ) return 1; - for(jj=0; jj<pIndex->nKeyCol; jj++){ - if( pExpr->iColumn==pIndex->aiColumn[jj] ) return 1; - } - }else if( (aColExpr = pIndex->aColExpr)!=0 ){ - for(jj=0; jj<pIndex->nKeyCol; jj++){ - if( pIndex->aiColumn[jj]!=XN_EXPR ) continue; - if( sqlite3ExprCompare(pExpr,aColExpr->a[jj].pExpr,iCursor)==0 ){ - return 1; - } - } - } - } - return 0; -} - -/* -** Return a bitmask where 1s indicate that the corresponding column of -** the table is used by an index. Only the first 63 columns are considered. -*/ -static Bitmask columnsInIndex(Index *pIdx){ - Bitmask m = 0; - int j; - for(j=pIdx->nColumn-1; j>=0; j--){ - int x = pIdx->aiColumn[j]; - if( x>=0 ){ - testcase( x==BMS-1 ); - testcase( x==BMS-2 ); - if( x<BMS-1 ) m |= MASKBIT(x); - } - } - return m; -} - -/* Check to see if a partial index with pPartIndexWhere can be used -** in the current query. Return true if it can be and false if not. -*/ -static int whereUsablePartialIndex(int iTab, WhereClause *pWC, Expr *pWhere){ - int i; - WhereTerm *pTerm; - while( pWhere->op==TK_AND ){ - if( !whereUsablePartialIndex(iTab,pWC,pWhere->pLeft) ) return 0; - pWhere = pWhere->pRight; - } - for(i=0, pTerm=pWC->a; i<pWC->nTerm; i++, pTerm++){ - Expr *pExpr = pTerm->pExpr; - if( sqlite3ExprImpliesExpr(pExpr, pWhere, iTab) - && (!ExprHasProperty(pExpr, EP_FromJoin) || pExpr->iRightJoinTable==iTab) - ){ - return 1; - } - } - return 0; -} - -/* -** 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 */ - Bitmask mExtra /* Extra prerequesites for using this table */ -){ - WhereInfo *pWInfo; /* WHERE analysis context */ - Index *pProbe; /* An index we are evaluating */ - Index sPk; /* A fake index object for the primary key */ - 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 */ - WhereLoop *pNew; /* Template WhereLoop object */ - int rc = SQLITE_OK; /* Return code */ - int iSortIdx = 1; /* Index number */ - int b; /* A boolean value */ - LogEst rSize; /* number of rows in the table */ - LogEst rLogSize; /* Logarithm of the number of rows in the table */ - WhereClause *pWC; /* The parsed WHERE clause */ - Table *pTab; /* Table being queried */ - - pNew = pBuilder->pNew; - pWInfo = pBuilder->pWInfo; - pTabList = pWInfo->pTabList; - pSrc = pTabList->a + pNew->iTab; - pTab = pSrc->pTab; - pWC = pBuilder->pWC; - assert( !IsVirtual(pSrc->pTab) ); - - if( pSrc->pIBIndex ){ - /* An INDEXED BY clause specifies a particular index to use */ - pProbe = pSrc->pIBIndex; - }else if( !HasRowid(pTab) ){ - pProbe = pTab->pIndex; - }else{ - /* There is no INDEXED BY clause. Create a fake Index object in local - ** variable sPk to represent the rowid primary key index. Make this - ** fake index the first in a chain of Index objects with all of the real - ** indices to follow */ - 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; - sPk.pTable = pTab; - sPk.szIdxRow = pTab->szTabRow; - aiRowEstPk[0] = pTab->nRowLogEst; - aiRowEstPk[1] = 0; - pFirst = pSrc->pTab->pIndex; - if( pSrc->fg.notIndexed==0 ){ - /* The real indices of the table are only considered if the - ** NOT INDEXED qualifier is omitted from the FROM clause */ - sPk.pNext = pFirst; - } - pProbe = &sPk; - } - rSize = pTab->nRowLogEst; - rLogSize = estLog(rSize); - -#ifndef SQLITE_OMIT_AUTOMATIC_INDEX - /* Automatic indexes */ - if( !pBuilder->pOrSet /* Not part of an OR optimization */ - && (pWInfo->wctrlFlags & WHERE_NO_AUTOINDEX)==0 - && (pWInfo->pParse->db->flags & SQLITE_AutoIndex)!=0 - && pSrc->pIBIndex==0 /* Has no INDEXED BY clause */ - && !pSrc->fg.notIndexed /* Has no NOT INDEXED clause */ - && HasRowid(pTab) /* Not WITHOUT ROWID table. (FIXME: Why not?) */ - && !pSrc->fg.isCorrelated /* Not a correlated subquery */ - && !pSrc->fg.isRecursive /* Not a recursive common table expression. */ - ){ - /* Generate auto-index WhereLoops */ - WhereTerm *pTerm; - WhereTerm *pWCEnd = pWC->a + pWC->nTerm; - for(pTerm=pWC->a; rc==SQLITE_OK && pTerm<pWCEnd; pTerm++){ - if( pTerm->prereqRight & pNew->maskSelf ) continue; - if( termCanDriveIndex(pTerm, pSrc, 0) ){ - pNew->u.btree.nEq = 1; - 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 - ** 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 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); - pNew->wsFlags = WHERE_AUTO_INDEX; - pNew->prereq = mExtra | pTerm->prereqRight; - rc = whereLoopInsert(pBuilder, pNew); - } - } - } -#endif /* SQLITE_OMIT_AUTOMATIC_INDEX */ - - /* Loop over all indices - */ - for(; rc==SQLITE_OK && pProbe; pProbe=pProbe->pNext, iSortIdx++){ - if( pProbe->pPartIdxWhere!=0 - && !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->nSkip = 0; - pNew->nLTerm = 0; - pNew->iSortIdx = 0; - pNew->rSetup = 0; - pNew->prereq = mExtra; - pNew->nOut = rSize; - pNew->u.btree.pIndex = pProbe; - b = indexMightHelpWithOrderBy(pBuilder, pProbe, pSrc->iCursor); - /* The ONEPASS_DESIRED flags never occurs together with ORDER BY */ - assert( (pWInfo->wctrlFlags & WHERE_ONEPASS_DESIRED)==0 || b==0 ); - if( pProbe->tnum<=0 ){ - /* Integer primary key index */ - pNew->wsFlags = WHERE_IPK; - - /* Full table scan */ - pNew->iSortIdx = b ? iSortIdx : 0; - /* TUNING: Cost of full table scan is (N*3.0). */ - pNew->rRun = rSize + 16; - ApplyCostMultiplier(pNew->rRun, pTab->costMult); - whereLoopOutputAdjust(pWC, pNew, rSize); - rc = whereLoopInsert(pBuilder, pNew); - pNew->nOut = rSize; - if( rc ) break; - }else{ - Bitmask m; - if( pProbe->isCovering ){ - pNew->wsFlags = WHERE_IDX_ONLY | WHERE_INDEXED; - m = 0; - }else{ - m = pSrc->colUsed & ~columnsInIndex(pProbe); - pNew->wsFlags = (m==0) ? (WHERE_IDX_ONLY|WHERE_INDEXED) : WHERE_INDEXED; - } - - /* Full scan via index */ - if( b - || !HasRowid(pTab) - || ( m==0 - && pProbe->bUnordered==0 - && (pProbe->szIdxRow<pTab->szTabRow) - && (pWInfo->wctrlFlags & WHERE_ONEPASS_DESIRED)==0 - && sqlite3GlobalConfig.bUseCis - && OptimizationEnabled(pWInfo->pParse->db, SQLITE_CoverIdxScan) - ) - ){ - pNew->iSortIdx = b ? iSortIdx : 0; - - /* 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, rSize); - rc = whereLoopInsert(pBuilder, pNew); - pNew->nOut = rSize; - if( rc ) break; - } - } - - rc = whereLoopAddBtreeIndex(pBuilder, pSrc, pProbe, 0); -#ifdef SQLITE_ENABLE_STAT3_OR_STAT4 - sqlite3Stat4ProbeFree(pBuilder->pRec); - pBuilder->nRecValid = 0; - pBuilder->pRec = 0; -#endif - - /* If there was an INDEXED BY clause, then only that one index is - ** considered. */ - if( pSrc->pIBIndex ) break; - } - return rc; -} - -#ifndef SQLITE_OMIT_VIRTUALTABLE -/* -** Add all WhereLoop objects for a table of the join identified by -** pBuilder->pNew->iTab. That table is guaranteed to be a virtual table. -** -** If there are no LEFT or CROSS JOIN joins in the query, both mExtra and -** mUnusable are set to 0. Otherwise, mExtra is a mask of all FROM clause -** entries that occur before the virtual table in the FROM clause and are -** separated from it by at least one LEFT or CROSS JOIN. Similarly, the -** mUnusable mask contains all FROM clause entries that occur after the -** virtual table and are separated from it by at least one LEFT or -** CROSS JOIN. -** -** For example, if the query were: -** -** ... FROM t1, t2 LEFT JOIN t3, t4, vt CROSS JOIN t5, t6; -** -** then mExtra corresponds to (t1, t2) and mUnusable to (t5, t6). -** -** All the tables in mExtra must be scanned before the current virtual -** table. So any terms for which all prerequisites are satisfied by -** mExtra may be specified as "usable" in all calls to xBestIndex. -** Conversely, all tables in mUnusable must be scanned after the current -** virtual table, so any terms for which the prerequisites overlap with -** mUnusable should always be configured as "not-usable" for xBestIndex. -*/ -static int whereLoopAddVirtual( - WhereLoopBuilder *pBuilder, /* WHERE clause information */ - Bitmask mExtra, /* Tables that must be scanned before this one */ - Bitmask mUnusable /* Tables that must be scanned after this one */ -){ - WhereInfo *pWInfo; /* WHERE analysis context */ - Parse *pParse; /* The parsing context */ - WhereClause *pWC; /* The WHERE clause */ - struct SrcList_item *pSrc; /* The FROM clause term to search */ - Table *pTab; - sqlite3 *db; - sqlite3_index_info *pIdxInfo; - struct sqlite3_index_constraint *pIdxCons; - struct sqlite3_index_constraint_usage *pUsage; - WhereTerm *pTerm; - int i, j; - int iTerm, mxTerm; - int nConstraint; - int seenIn = 0; /* True if an IN operator is seen */ - int seenVar = 0; /* True if a non-constant constraint is seen */ - int iPhase; /* 0: const w/o IN, 1: const, 2: no IN, 2: IN */ - WhereLoop *pNew; - int rc = SQLITE_OK; - - assert( (mExtra & mUnusable)==0 ); - pWInfo = pBuilder->pWInfo; - pParse = pWInfo->pParse; - db = pParse->db; - pWC = pBuilder->pWC; - pNew = pBuilder->pNew; - pSrc = &pWInfo->pTabList->a[pNew->iTab]; - pTab = pSrc->pTab; - assert( IsVirtual(pTab) ); - pIdxInfo = allocateIndexInfo(pParse, pWC, mUnusable, pSrc,pBuilder->pOrderBy); - if( pIdxInfo==0 ) return SQLITE_NOMEM; - pNew->prereq = 0; - pNew->rSetup = 0; - pNew->wsFlags = WHERE_VIRTUALTABLE; - pNew->nLTerm = 0; - pNew->u.vtab.needFree = 0; - pUsage = pIdxInfo->aConstraintUsage; - nConstraint = pIdxInfo->nConstraint; - if( whereLoopResize(db, pNew, nConstraint) ){ - sqlite3DbFree(db, pIdxInfo); - return SQLITE_NOMEM; - } - - for(iPhase=0; iPhase<=3; iPhase++){ - if( !seenIn && (iPhase&1)!=0 ){ - iPhase++; - if( iPhase>3 ) break; - } - if( !seenVar && iPhase>1 ) break; - pIdxCons = *(struct sqlite3_index_constraint**)&pIdxInfo->aConstraint; - for(i=0; i<pIdxInfo->nConstraint; i++, pIdxCons++){ - j = pIdxCons->iTermOffset; - pTerm = &pWC->a[j]; - switch( iPhase ){ - case 0: /* Constants without IN operator */ - pIdxCons->usable = 0; - if( (pTerm->eOperator & WO_IN)!=0 ){ - seenIn = 1; - } - if( (pTerm->prereqRight & ~mExtra)!=0 ){ - seenVar = 1; - }else if( (pTerm->eOperator & WO_IN)==0 ){ - pIdxCons->usable = 1; - } - break; - case 1: /* Constants with IN operators */ - assert( seenIn ); - pIdxCons->usable = (pTerm->prereqRight & ~mExtra)==0; - break; - case 2: /* Variables without IN */ - assert( seenVar ); - pIdxCons->usable = (pTerm->eOperator & WO_IN)==0; - break; - default: /* Variables with IN */ - assert( seenVar && seenIn ); - pIdxCons->usable = 1; - break; - } - } - memset(pUsage, 0, sizeof(pUsage[0])*pIdxInfo->nConstraint); - if( pIdxInfo->needToFreeIdxStr ) sqlite3_free(pIdxInfo->idxStr); - pIdxInfo->idxStr = 0; - pIdxInfo->idxNum = 0; - pIdxInfo->needToFreeIdxStr = 0; - pIdxInfo->orderByConsumed = 0; - pIdxInfo->estimatedCost = SQLITE_BIG_DBL / (double)2; - pIdxInfo->estimatedRows = 25; - pIdxInfo->idxFlags = 0; - rc = vtabBestIndex(pParse, pTab, pIdxInfo); - if( rc ) goto whereLoopAddVtab_exit; - pIdxCons = *(struct sqlite3_index_constraint**)&pIdxInfo->aConstraint; - pNew->prereq = mExtra; - mxTerm = -1; - assert( pNew->nLSlot>=nConstraint ); - for(i=0; i<nConstraint; i++) pNew->aLTerm[i] = 0; - pNew->u.vtab.omitMask = 0; - for(i=0; i<nConstraint; i++, pIdxCons++){ - if( (iTerm = pUsage[i].argvIndex - 1)>=0 ){ - j = pIdxCons->iTermOffset; - if( iTerm>=nConstraint - || j<0 - || j>=pWC->nTerm - || pNew->aLTerm[iTerm]!=0 - ){ - rc = SQLITE_ERROR; - sqlite3ErrorMsg(pParse, "%s.xBestIndex() malfunction", pTab->zName); - goto whereLoopAddVtab_exit; - } - testcase( iTerm==nConstraint-1 ); - testcase( j==0 ); - testcase( j==pWC->nTerm-1 ); - pTerm = &pWC->a[j]; - pNew->prereq |= pTerm->prereqRight; - assert( iTerm<pNew->nLSlot ); - pNew->aLTerm[iTerm] = pTerm; - if( iTerm>mxTerm ) mxTerm = iTerm; - testcase( iTerm==15 ); - testcase( iTerm==16 ); - if( iTerm<16 && pUsage[i].omit ) pNew->u.vtab.omitMask |= 1<<iTerm; - if( (pTerm->eOperator & WO_IN)!=0 ){ - if( pUsage[i].omit==0 ){ - /* Do not attempt to use an IN constraint if the virtual table - ** says that the equivalent EQ constraint cannot be safely omitted. - ** If we do attempt to use such a constraint, some rows might be - ** repeated in the output. */ - break; - } - /* A virtual table that is constrained by an IN clause may not - ** consume the ORDER BY clause because (1) the order of IN terms - ** is not necessarily related to the order of output terms and - ** (2) Multiple outputs from a single IN value will not merge - ** together. */ - pIdxInfo->orderByConsumed = 0; - pIdxInfo->idxFlags &= ~SQLITE_INDEX_SCAN_UNIQUE; - } - } - } - if( i>=nConstraint ){ - pNew->nLTerm = mxTerm+1; - assert( pNew->nLTerm<=pNew->nLSlot ); - pNew->u.vtab.idxNum = pIdxInfo->idxNum; - pNew->u.vtab.needFree = pIdxInfo->needToFreeIdxStr; - pIdxInfo->needToFreeIdxStr = 0; - pNew->u.vtab.idxStr = pIdxInfo->idxStr; - pNew->u.vtab.isOrdered = (i8)(pIdxInfo->orderByConsumed ? - pIdxInfo->nOrderBy : 0); - pNew->rSetup = 0; - pNew->rRun = sqlite3LogEstFromDouble(pIdxInfo->estimatedCost); - pNew->nOut = sqlite3LogEst(pIdxInfo->estimatedRows); - - /* Set the WHERE_ONEROW flag if the xBestIndex() method indicated - ** that the scan will visit at most one row. Clear it otherwise. */ - if( pIdxInfo->idxFlags & SQLITE_INDEX_SCAN_UNIQUE ){ - pNew->wsFlags |= WHERE_ONEROW; - }else{ - pNew->wsFlags &= ~WHERE_ONEROW; - } - whereLoopInsert(pBuilder, pNew); - if( pNew->u.vtab.needFree ){ - sqlite3_free(pNew->u.vtab.idxStr); - pNew->u.vtab.needFree = 0; - } - } - } - -whereLoopAddVtab_exit: - if( pIdxInfo->needToFreeIdxStr ) sqlite3_free(pIdxInfo->idxStr); - sqlite3DbFree(db, pIdxInfo); - return rc; -} -#endif /* SQLITE_OMIT_VIRTUALTABLE */ - -/* -** Add WhereLoop entries to handle OR terms. This works for either -** btrees or virtual tables. -*/ -static int whereLoopAddOr( - WhereLoopBuilder *pBuilder, - Bitmask mExtra, - Bitmask mUnusable -){ - WhereInfo *pWInfo = pBuilder->pWInfo; - WhereClause *pWC; - WhereLoop *pNew; - WhereTerm *pTerm, *pWCEnd; - int rc = SQLITE_OK; - int iCur; - WhereClause tempWC; - WhereLoopBuilder sSubBuild; - WhereOrSet sSum, sCur; - struct SrcList_item *pItem; - - pWC = pBuilder->pWC; - pWCEnd = pWC->a + pWC->nTerm; - pNew = pBuilder->pNew; - memset(&sSum, 0, sizeof(sSum)); - pItem = pWInfo->pTabList->a + pNew->iTab; - iCur = pItem->iCursor; - - for(pTerm=pWC->a; pTerm<pWCEnd && rc==SQLITE_OK; pTerm++){ - if( (pTerm->eOperator & WO_OR)!=0 - && (pTerm->u.pOrInfo->indexable & pNew->maskSelf)!=0 - ){ - WhereClause * const pOrWC = &pTerm->u.pOrInfo->wc; - WhereTerm * const pOrWCEnd = &pOrWC->a[pOrWC->nTerm]; - WhereTerm *pOrTerm; - int once = 1; - int i, j; - - sSubBuild = *pBuilder; - 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; - }else if( pOrTerm->leftCursor==iCur ){ - tempWC.pWInfo = pWC->pWInfo; - tempWC.pOuter = pWC; - tempWC.op = TK_AND; - tempWC.nTerm = 1; - tempWC.a = pOrTerm; - sSubBuild.pWC = &tempWC; - }else{ - 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, mUnusable); - }else -#endif - { - rc = whereLoopAddBtree(&sSubBuild, mExtra); - } - if( rc==SQLITE_OK ){ - rc = whereLoopAddOr(&sSubBuild, mExtra, mUnusable); - } - assert( rc==SQLITE_OK || sCur.n==0 ); - if( sCur.n==0 ){ - sSum.n = 0; - break; - }else if( once ){ - whereOrMove(&sSum, &sCur); - once = 0; - }else{ - WhereOrSet sPrev; - whereOrMove(&sPrev, &sSum); - sSum.n = 0; - for(i=0; i<sPrev.n; i++){ - for(j=0; j<sCur.n; j++){ - whereOrInsert(&sSum, sPrev.a[i].prereq | sCur.a[j].prereq, - sqlite3LogEstAdd(sPrev.a[i].rRun, sCur.a[j].rRun), - sqlite3LogEstAdd(sPrev.a[i].nOut, sCur.a[j].nOut)); - } - } - } - } - pNew->nLTerm = 1; - pNew->aLTerm[0] = pTerm; - pNew->wsFlags = WHERE_MULTI_OR; - pNew->rSetup = 0; - pNew->iSortIdx = 0; - memset(&pNew->u, 0, sizeof(pNew->u)); - for(i=0; rc==SQLITE_OK && i<sSum.n; i++){ - /* 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); - } - WHERETRACE(0x200, ("End processing OR-clause %p\n", pTerm)); - } - } - return rc; -} - -/* -** Add all WhereLoop objects for all tables -*/ -static int whereLoopAddAll(WhereLoopBuilder *pBuilder){ - WhereInfo *pWInfo = pBuilder->pWInfo; - Bitmask mExtra = 0; - Bitmask mPrior = 0; - int iTab; - SrcList *pTabList = pWInfo->pTabList; - struct SrcList_item *pItem; - struct SrcList_item *pEnd = &pTabList->a[pWInfo->nLevel]; - sqlite3 *db = pWInfo->pParse->db; - int rc = SQLITE_OK; - WhereLoop *pNew; - u8 priorJointype = 0; - - /* Loop over the tables in the join, from left to right */ - pNew = pBuilder->pNew; - whereLoopInit(pNew); - for(iTab=0, pItem=pTabList->a; pItem<pEnd; iTab++, pItem++){ - Bitmask mUnusable = 0; - pNew->iTab = iTab; - pNew->maskSelf = sqlite3WhereGetMask(&pWInfo->sMaskSet, pItem->iCursor); - if( ((pItem->fg.jointype|priorJointype) & (JT_LEFT|JT_CROSS))!=0 ){ - /* This condition is true when pItem is the FROM clause term on the - ** right-hand-side of a LEFT or CROSS JOIN. */ - mExtra = mPrior; - } - priorJointype = pItem->fg.jointype; - if( IsVirtual(pItem->pTab) ){ - struct SrcList_item *p; - for(p=&pItem[1]; p<pEnd; p++){ - if( mUnusable || (p->fg.jointype & (JT_LEFT|JT_CROSS)) ){ - mUnusable |= sqlite3WhereGetMask(&pWInfo->sMaskSet, p->iCursor); - } - } - rc = whereLoopAddVirtual(pBuilder, mExtra, mUnusable); - }else{ - rc = whereLoopAddBtree(pBuilder, mExtra); - } - if( rc==SQLITE_OK ){ - rc = whereLoopAddOr(pBuilder, mExtra, mUnusable); - } - mPrior |= pNew->maskSelf; - if( rc || db->mallocFailed ) break; - } - - whereLoopClear(db, pNew); - return rc; -} - -/* -** 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 N: -** -** 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 DISTINCT do not require rows to appear in any particular order as long -** 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. -*/ -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 */ - u16 wctrlFlags, /* Might contain WHERE_GROUPBY or WHERE_DISTINCTBY */ - u16 nLoop, /* Number of entries in pPath->aLoop[] */ - WhereLoop *pLast, /* Add this WhereLoop to the end of pPath->aLoop[] */ - Bitmask *pRevMask /* OUT: Mask of WhereLoops to run in reverse order */ -){ - u8 revSet; /* True if rev is known */ - u8 rev; /* Composite sort order */ - u8 revIdx; /* Index sort order */ - u8 isOrderDistinct; /* All prior WhereLoops are order-distinct */ - u8 distinctColumns; /* True if the loop has UNIQUE NOT NULL columns */ - u8 isMatch; /* iColumn matches a term of the ORDER BY clause */ - u16 nKeyCol; /* Number of key columns in pIndex */ - u16 nColumn; /* Total number of ordered columns in the index */ - u16 nOrderBy; /* Number terms in the ORDER BY clause */ - int iLoop; /* Index of WhereLoop in pPath being processed */ - int i, j; /* Loop counters */ - int iCur; /* Cursor number for current WhereLoop */ - int iColumn; /* A column number within table iCur */ - WhereLoop *pLoop = 0; /* Current WhereLoop being processed. */ - WhereTerm *pTerm; /* A single term of the WHERE clause */ - Expr *pOBExpr; /* An expression from the ORDER BY clause */ - CollSeq *pColl; /* COLLATE function from an ORDER BY clause term */ - Index *pIndex; /* The index associated with pLoop */ - sqlite3 *db = pWInfo->pParse->db; /* Database connection */ - Bitmask obSat = 0; /* Mask of ORDER BY terms satisfied so far */ - Bitmask obDone; /* Mask of all ORDER BY terms */ - Bitmask orderDistinctMask; /* Mask of all well-ordered loops */ - Bitmask ready; /* Mask of inner loops */ - - /* - ** We say the WhereLoop is "one-row" if it generates no more than one - ** row of output. A WhereLoop is one-row if all of the following are true: - ** (a) All index columns match with WHERE_COLUMN_EQ. - ** (b) The index is unique - ** Any WhereLoop with an WHERE_COLUMN_EQ constraint on the rowid is one-row. - ** Every one-row WhereLoop will have the WHERE_ONEROW bit set in wsFlags. - ** - ** We say the WhereLoop is "order-distinct" if the set of columns from - ** that WhereLoop that are in the ORDER BY clause are different for every - ** row of the WhereLoop. Every one-row WhereLoop is automatically - ** order-distinct. A WhereLoop that has no columns in the ORDER BY clause - ** is not order-distinct. To be order-distinct is not quite the same as being - ** UNIQUE since a UNIQUE column or index can have multiple rows that - ** are NULL and NULL values are equivalent for the purpose of order-distinct. - ** To be order-distinct, the columns must be UNIQUE and NOT NULL. - ** - ** The rowid for a table is always UNIQUE and NOT NULL so whenever the - ** rowid appears in the ORDER BY clause, the corresponding WhereLoop is - ** automatically order-distinct. - */ - - assert( pOrderBy!=0 ); - if( nLoop && OptimizationDisabled(db, SQLITE_OrderByIdxJoin) ) return 0; - - nOrderBy = pOrderBy->nExpr; - testcase( nOrderBy==BMS-1 ); - if( nOrderBy>BMS-1 ) return 0; /* Cannot optimize overly large ORDER BYs */ - isOrderDistinct = 1; - obDone = MASKBIT(nOrderBy)-1; - orderDistinctMask = 0; - ready = 0; - for(iLoop=0; isOrderDistinct && obSat<obDone && iLoop<=nLoop; iLoop++){ - if( iLoop>0 ) ready |= pLoop->maskSelf; - pLoop = iLoop<nLoop ? pPath->aLoop[iLoop] : pLast; - 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 - ** the current loop for which there is term in the WHERE - ** clause of the form X IS NULL or X=? that reference only outer - ** loops. - */ - for(i=0; i<nOrderBy; i++){ - if( MASKBIT(i) & obSat ) continue; - pOBExpr = sqlite3ExprSkipCollate(pOrderBy->a[i].pExpr); - if( pOBExpr->op!=TK_COLUMN ) continue; - if( pOBExpr->iTable!=iCur ) continue; - pTerm = sqlite3WhereFindTerm(&pWInfo->sWC, iCur, pOBExpr->iColumn, - ~ready, WO_EQ|WO_ISNULL|WO_IS, 0); - if( pTerm==0 ) continue; - if( (pTerm->eOperator&(WO_EQ|WO_IS))!=0 && pOBExpr->iColumn>=0 ){ - const char *z1, *z2; - pColl = sqlite3ExprCollSeq(pWInfo->pParse, pOrderBy->a[i].pExpr); - if( !pColl ) pColl = db->pDfltColl; - z1 = pColl->zName; - pColl = sqlite3ExprCollSeq(pWInfo->pParse, pTerm->pExpr); - if( !pColl ) pColl = db->pDfltColl; - z2 = pColl->zName; - if( sqlite3StrICmp(z1, z2)!=0 ) continue; - testcase( pTerm->pExpr->op==TK_IS ); - } - obSat |= MASKBIT(i); - } - - if( (pLoop->wsFlags & WHERE_ONEROW)==0 ){ - if( pLoop->wsFlags & WHERE_IPK ){ - pIndex = 0; - nKeyCol = 0; - nColumn = 1; - }else if( (pIndex = pLoop->u.btree.pIndex)==0 || pIndex->bUnordered ){ - return 0; - }else{ - nKeyCol = pIndex->nKeyCol; - nColumn = pIndex->nColumn; - assert( nColumn==nKeyCol+1 || !HasRowid(pIndex->pTable) ); - assert( pIndex->aiColumn[nColumn-1]==XN_ROWID - || !HasRowid(pIndex->pTable)); - isOrderDistinct = IsUniqueIndex(pIndex); - } - - /* Loop through all columns of the index and deal with the ones - ** that are not constrained by == or IN. - */ - rev = revSet = 0; - distinctColumns = 0; - for(j=0; j<nColumn; j++){ - u8 bOnce; /* True to run the ORDER BY search loop */ - - /* Skip over == and IS NULL terms */ - if( j<pLoop->u.btree.nEq - && pLoop->nSkip==0 - && ((i = pLoop->aLTerm[j]->eOperator) & (WO_EQ|WO_ISNULL|WO_IS))!=0 - ){ - if( i & WO_ISNULL ){ - testcase( isOrderDistinct ); - isOrderDistinct = 0; - } - continue; - } - - /* Get the column number in the table (iColumn) and sort order - ** (revIdx) for the j-th column of the index. - */ - if( pIndex ){ - iColumn = pIndex->aiColumn[j]; - revIdx = pIndex->aSortOrder[j]; - if( iColumn==pIndex->pTable->iPKey ) iColumn = -1; - }else{ - iColumn = XN_ROWID; - revIdx = 0; - } - - /* An unconstrained column that might be NULL means that this - ** WhereLoop is not well-ordered - */ - if( isOrderDistinct - && iColumn>=0 - && j>=pLoop->u.btree.nEq - && pIndex->pTable->aCol[iColumn].notNull==0 - ){ - isOrderDistinct = 0; - } - - /* Find the ORDER BY term that corresponds to the j-th column - ** of the index and mark that ORDER BY term off - */ - bOnce = 1; - isMatch = 0; - for(i=0; bOnce && i<nOrderBy; i++){ - if( MASKBIT(i) & obSat ) continue; - pOBExpr = sqlite3ExprSkipCollate(pOrderBy->a[i].pExpr); - testcase( wctrlFlags & WHERE_GROUPBY ); - testcase( wctrlFlags & WHERE_DISTINCTBY ); - if( (wctrlFlags & (WHERE_GROUPBY|WHERE_DISTINCTBY))==0 ) bOnce = 0; - if( iColumn>=(-1) ){ - if( pOBExpr->op!=TK_COLUMN ) continue; - if( pOBExpr->iTable!=iCur ) continue; - if( pOBExpr->iColumn!=iColumn ) continue; - }else{ - if( sqlite3ExprCompare(pOBExpr,pIndex->aColExpr->a[j].pExpr,iCur) ){ - continue; - } - } - if( iColumn>=0 ){ - pColl = sqlite3ExprCollSeq(pWInfo->pParse, pOrderBy->a[i].pExpr); - if( !pColl ) pColl = db->pDfltColl; - if( sqlite3StrICmp(pColl->zName, pIndex->azColl[j])!=0 ) continue; - } - isMatch = 1; - break; - } - 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 ){ - 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); - }else{ - /* No match found */ - if( j==0 || j<nKeyCol ){ - testcase( isOrderDistinct!=0 ); - isOrderDistinct = 0; - } - break; - } - } /* end Loop over all index columns */ - if( distinctColumns ){ - testcase( isOrderDistinct==0 ); - isOrderDistinct = 1; - } - } /* end-if not one-row */ - - /* Mark off any other ORDER BY terms that reference pLoop */ - if( isOrderDistinct ){ - orderDistinctMask |= pLoop->maskSelf; - for(i=0; i<nOrderBy; i++){ - Expr *p; - Bitmask mTerm; - if( MASKBIT(i) & obSat ) continue; - p = pOrderBy->a[i].pExpr; - mTerm = sqlite3WhereExprUsage(&pWInfo->sMaskSet,p); - if( mTerm==0 && !sqlite3ExprIsConstant(p) ) continue; - if( (mTerm&~orderDistinctMask)==0 ){ - obSat |= MASKBIT(i); - } - } - } - } /* End the loop over all WhereLoops from outer-most down to inner-most */ - 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){ - static char zName[65]; - int i; - for(i=0; i<nLoop; i++){ zName[i] = pPath->aLoop[i]->cId; } - if( pLast ) zName[i++] = pLast->cId; - zName[i] = 0; - return zName; -} -#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. -** -** Assume that the total number of output rows that will need to be sorted -** will be nRowEst (in the 10*log2 representation). Or, ignore sorting -** costs if nRowEst==0. -** -** Return SQLITE_OK on success or SQLITE_NOMEM of a memory allocation -** error occurs. -*/ -static int wherePathSolver(WhereInfo *pWInfo, LogEst nRowEst){ - int mxChoice; /* Maximum number of simultaneous paths tracked */ - int nLoop; /* Number of terms in the join */ - Parse *pParse; /* Parsing context */ - sqlite3 *db; /* The database connection */ - int iLoop; /* Loop counter over the terms of the join */ - int ii, jj; /* Loop counters */ - int mxI = 0; /* Index of next entry to replace */ - int nOrderBy; /* Number of ORDER BY clause terms */ - 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 */ - WherePath *pFrom; /* An element of aFrom[] that we are working on */ - 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; - nLoop = pWInfo->nLevel; - /* 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); - assert( nLoop<=pWInfo->pTabList->nSrc ); - 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, 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; - memset(aFrom, 0, sizeof(aFrom[0])); - pX = (WhereLoop**)(aFrom+mxChoice); - 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. - ** - ** TUNING: Do not let the number of iterations go above 28. If the cost - ** of computing an automatic index is not paid back within the first 28 - ** rows, then do not use the automatic index. */ - aFrom[0].nRow = MIN(pParse->nQueryLoop, 48); assert( 48==sqlite3LogEst(28) ); - nFrom = 1; - 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 - ** of WherePaths as the basis for the next. Keep track of the mxChoice - ** best paths at each generation */ - for(iLoop=0; iLoop<nLoop; iLoop++){ - nTo = 0; - for(ii=0, pFrom=aFrom; ii<nFrom; ii++, pFrom++){ - for(pWLoop=pWInfo->pLoops; pWLoop; pWLoop=pWLoop->pNextLoop){ - 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 */ - 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); - }else{ - revMask = pFrom->revLoop; - } - 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)&0x80)==0 - ){ - testcase( jj==nTo-1 ); - break; - } - } - if( jj>=nTo ){ - /* 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, - isOrdered>=0 ? isOrdered+'0' : '?'); - } -#endif - continue; - } - /* 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++; - }else{ - /* New path replaces the prior worst to keep count below mxChoice */ - jj = mxI; - } - pTo = &aTo[jj]; -#ifdef WHERETRACE_ENABLED /* 0x4 */ - if( sqlite3WhereTrace&0x4 ){ - sqlite3DebugPrintf("New %s cost=%-3d,%3d order=%c\n", - wherePathName(pFrom, iLoop, pWLoop), rCost, nOut, - isOrdered>=0 ? isOrdered+'0' : '?'); - } -#endif - }else{ - /* 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, - isOrdered>=0 ? isOrdered+'0' : '?'); - sqlite3DebugPrintf(" vs %s cost=%-3d,%d order=%c\n", - wherePathName(pTo, iLoop+1, 0), pTo->rCost, pTo->nRow, - pTo->isOrdered>=0 ? pTo->isOrdered+'0' : '?'); - } -#endif - /* Discard the candidate path from further consideration */ - testcase( pTo->rCost==rCost ); - continue; - } - testcase( pTo->rCost==rCost+1 ); - /* 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, - isOrdered>=0 ? isOrdered+'0' : '?'); - sqlite3DebugPrintf(" was %s cost=%-3d,%3d order=%c\n", - wherePathName(pTo, iLoop+1, 0), pTo->rCost, pTo->nRow, - pTo->isOrdered>=0 ? pTo->isOrdered+'0' : '?'); - } -#endif - } - /* pWLoop is a winner. Add it to the set of best so far */ - pTo->maskLoop = pFrom->maskLoop | pWLoop->maskSelf; - 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 - || (pTo->rCost==mxCost && pTo->rUnsorted>mxUnsorted) - ){ - mxCost = pTo->rCost; - mxUnsorted = pTo->rUnsorted; - mxI = jj; - } - } - } - } - } - -#ifdef WHERETRACE_ENABLED /* >=2 */ - if( sqlite3WhereTrace & 0x02 ){ - sqlite3DebugPrintf("---- after round %d ----\n", iLoop); - for(ii=0, pTo=aTo; ii<nTo; ii++, pTo++){ - sqlite3DebugPrintf(" %s cost=%-3d nrow=%-3d order=%c", - wherePathName(pTo, iLoop+1, 0), pTo->rCost, pTo->nRow, - pTo->isOrdered>=0 ? (pTo->isOrdered+'0') : '?'); - if( pTo->isOrdered>0 ){ - sqlite3DebugPrintf(" rev=0x%llx\n", pTo->revLoop); - }else{ - sqlite3DebugPrintf("\n"); - } - } - } -#endif - - /* Swap the roles of aFrom and aTo for the next generation */ - pFrom = aTo; - aTo = aFrom; - aFrom = pFrom; - nFrom = nTo; - } - - if( nFrom==0 ){ - sqlite3ErrorMsg(pParse, "no query solution"); - sqlite3DbFree(db, pSpace); - return SQLITE_ERROR; - } - - /* Find the lowest cost path. pFrom will be left pointing to that path */ - pFrom = aFrom; - for(ii=1; ii<nFrom; ii++){ - if( pFrom->rCost>aFrom[ii].rCost ) pFrom = &aFrom[ii]; - } - assert( pWInfo->nLevel==nLoop ); - /* Load the lowest cost path into pWInfo */ - for(iLoop=0; iLoop<nLoop; iLoop++){ - WhereLevel *pLevel = pWInfo->a + iLoop; - pLevel->pWLoop = pWLoop = pFrom->aLoop[iLoop]; - pLevel->iFrom = pWLoop->iTab; - pLevel->iTabCur = pWInfo->pTabList->a[pLevel->iFrom].iCursor; - } - if( (pWInfo->wctrlFlags & WHERE_WANT_DISTINCT)!=0 - && (pWInfo->wctrlFlags & WHERE_DISTINCTBY)==0 - && pWInfo->eDistinct==WHERE_DISTINCT_NOOP - && nRowEst - ){ - Bitmask notUsed; - int rc = wherePathSatisfiesOrderBy(pWInfo, pWInfo->pResultSet, pFrom, - WHERE_DISTINCTBY, nLoop-1, pFrom->aLoop[nLoop-1], ¬Used); - if( rc==pWInfo->pResultSet->nExpr ){ - pWInfo->eDistinct = WHERE_DISTINCT_ORDERED; - } - } - if( pWInfo->pOrderBy ){ - if( pWInfo->wctrlFlags & WHERE_DISTINCTBY ){ - if( pFrom->isOrdered==pWInfo->pOrderBy->nExpr ){ - pWInfo->eDistinct = WHERE_DISTINCT_ORDERED; - } - }else{ - 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 && nLoop>0 - ){ - Bitmask revMask = 0; - int nOrder = wherePathSatisfiesOrderBy(pWInfo, pWInfo->pOrderBy, - pFrom, 0, nLoop-1, pFrom->aLoop[nLoop-1], &revMask - ); - assert( pWInfo->sorted==0 ); - if( nOrder==pWInfo->pOrderBy->nExpr ){ - pWInfo->sorted = 1; - pWInfo->revMask = revMask; - } - } - } - - - pWInfo->nRowOut = pFrom->nRow; - - /* Free temporary memory and return success */ - sqlite3DbFree(db, pSpace); - return SQLITE_OK; -} - -/* -** Most queries use only a single table (they are not joins) and have -** simple == constraints against indexed fields. This routine attempts -** to plan those simple cases using much less ceremony than the -** general-purpose query planner, and thereby yield faster sqlite3_prepare() -** times for the common case. -** -** Return non-zero on success, if this query can be handled by this -** no-frills query planner. Return zero if this query needs the -** general-purpose query planner. -*/ -static int whereShortCut(WhereLoopBuilder *pBuilder){ - WhereInfo *pWInfo; - struct SrcList_item *pItem; - WhereClause *pWC; - WhereTerm *pTerm; - WhereLoop *pLoop; - int iCur; - int j; - Table *pTab; - Index *pIdx; - - pWInfo = pBuilder->pWInfo; - if( pWInfo->wctrlFlags & WHERE_FORCE_TABLE ) return 0; - assert( pWInfo->pTabList->nSrc>=1 ); - pItem = pWInfo->pTabList->a; - pTab = pItem->pTab; - if( IsVirtual(pTab) ) return 0; - if( pItem->fg.isIndexedBy ) return 0; - iCur = pItem->iCursor; - pWC = &pWInfo->sWC; - pLoop = pBuilder->pNew; - pLoop->wsFlags = 0; - pLoop->nSkip = 0; - pTerm = sqlite3WhereFindTerm(pWC, iCur, -1, 0, WO_EQ|WO_IS, 0); - if( pTerm ){ - testcase( pTerm->eOperator & WO_IS ); - pLoop->wsFlags = WHERE_COLUMN_EQ|WHERE_IPK|WHERE_ONEROW; - pLoop->aLTerm[0] = pTerm; - pLoop->nLTerm = 1; - pLoop->u.btree.nEq = 1; - /* TUNING: Cost of a rowid lookup is 10 */ - pLoop->rRun = 33; /* 33==sqlite3LogEst(10) */ - }else{ - for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){ - int opMask; - assert( pLoop->aLTermSpace==pLoop->aLTerm ); - if( !IsUniqueIndex(pIdx) - || pIdx->pPartIdxWhere!=0 - || pIdx->nKeyCol>ArraySize(pLoop->aLTermSpace) - ) continue; - opMask = pIdx->uniqNotNull ? (WO_EQ|WO_IS) : WO_EQ; - for(j=0; j<pIdx->nKeyCol; j++){ - pTerm = sqlite3WhereFindTerm(pWC, iCur, j, 0, opMask, pIdx); - if( pTerm==0 ) break; - testcase( pTerm->eOperator & WO_IS ); - pLoop->aLTerm[j] = pTerm; - } - if( j!=pIdx->nKeyCol ) continue; - pLoop->wsFlags = WHERE_COLUMN_EQ|WHERE_ONEROW|WHERE_INDEXED; - if( pIdx->isCovering || (pItem->colUsed & ~columnsInIndex(pIdx))==0 ){ - pLoop->wsFlags |= WHERE_IDX_ONLY; - } - pLoop->nLTerm = j; - pLoop->u.btree.nEq = j; - pLoop->u.btree.pIndex = pIdx; - /* TUNING: Cost of a unique index lookup is 15 */ - pLoop->rRun = 39; /* 39==sqlite3LogEst(15) */ - break; - } - } - if( pLoop->wsFlags ){ - pLoop->nOut = (LogEst)1; - pWInfo->a[0].pWLoop = pLoop; - pLoop->maskSelf = sqlite3WhereGetMask(&pWInfo->sMaskSet, iCur); - pWInfo->a[0].iTabCur = iCur; - pWInfo->nRowOut = 1; - if( pWInfo->pOrderBy ) pWInfo->nOBSat = pWInfo->pOrderBy->nExpr; - if( pWInfo->wctrlFlags & WHERE_WANT_DISTINCT ){ - pWInfo->eDistinct = WHERE_DISTINCT_UNIQUE; - } -#ifdef SQLITE_DEBUG - pLoop->cId = '0'; -#endif - return 1; - } - return 0; -} - -/* -** Generate the beginning of the loop used for WHERE clause processing. -** The return value is a pointer to an opaque structure that contains -** information needed to terminate the loop. Later, the calling routine -** should invoke sqlite3WhereEnd() with the return value of this function -** in order to complete the WHERE clause processing. -** -** If an error occurs, this routine returns NULL. -** -** The basic idea is to do a nested loop, one loop for each table in -** the FROM clause of a select. (INSERT and UPDATE statements are the -** same as a SELECT with only a single table in the FROM clause.) For -** example, if the SQL is this: -** -** SELECT * FROM t1, t2, t3 WHERE ...; -** -** Then the code generated is conceptually like the following: -** -** foreach row1 in t1 do \ Code generated -** foreach row2 in t2 do |-- by sqlite3WhereBegin() -** foreach row3 in t3 do / -** ... -** end \ Code generated -** end |-- by sqlite3WhereEnd() -** end / -** -** Note that the loops might not be nested in the order in which they -** appear in the FROM clause if a different order is better able to make -** use of indices. Note also that when the IN operator appears in -** the WHERE clause, it might result in additional nested loops for -** scanning through all values on the right-hand side of the IN. -** -** There are Btree cursors associated with each table. t1 uses cursor -** number pTabList->a[0].iCursor. t2 uses the cursor pTabList->a[1].iCursor. -** And so forth. This routine generates code to open those VDBE cursors -** and sqlite3WhereEnd() generates the code to close them. -** -** The code that sqlite3WhereBegin() generates leaves the cursors named -** in pTabList pointing at their appropriate entries. The [...] code -** can use OP_Column and OP_Rowid opcodes on these cursors to extract -** data from the various tables of the loop. -** -** If the WHERE clause is empty, the foreach loops must each scan their -** entire tables. Thus a three-way join is an O(N^3) operation. But if -** the tables have indices and there are terms in the WHERE clause that -** refer to those indices, a complete table scan can be avoided and the -** code will run much faster. Most of the work of this routine is checking -** to see if there are indices that can be used to speed up the loop. -** -** Terms of the WHERE clause are also used to limit which rows actually -** make it to the "..." in the middle of the loop. After each "foreach", -** terms of the WHERE clause that use only terms in that loop and outer -** loops are evaluated and if false a jump is made around all subsequent -** inner loops (or around the "..." if the test occurs within the inner- -** most loop) -** -** OUTER JOINS -** -** An outer join of tables t1 and t2 is conceptally coded as follows: -** -** foreach row1 in t1 do -** flag = 0 -** foreach row2 in t2 do -** start: -** ... -** flag = 1 -** end -** if flag==0 then -** move the row2 cursor to a null row -** goto start -** fi -** end -** -** ORDER BY CLAUSE PROCESSING -** -** pOrderBy is a pointer to the ORDER BY clause (or the GROUP BY clause -** if the WHERE_GROUPBY flag is set in wctrlFlags) of a SELECT statement -** if there is one. If there is no ORDER BY clause or if this routine -** is called from an UPDATE or DELETE statement, then pOrderBy is NULL. -** -** The iIdxCur parameter is the cursor number of an index. If -** WHERE_ONETABLE_ONLY is set, iIdxCur is the cursor number of an index -** to use for OR clause processing. The WHERE clause should use this -** specific cursor. If WHERE_ONEPASS_DESIRED is set, then iIdxCur is -** the first cursor in an array of cursors for all indices. iIdxCur should -** be used to compute the appropriate cursor depending on which index is -** used. -*/ -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 (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 */ -){ - int nByteWInfo; /* Num. bytes allocated for WhereInfo struct */ - int nTabList; /* Number of elements in pTabList */ - WhereInfo *pWInfo; /* Will become the return value of this function */ - Vdbe *v = pParse->pVdbe; /* The virtual database engine */ - Bitmask notReady; /* Cursors that are not yet positioned */ - WhereLoopBuilder sWLB; /* The WhereLoop builder */ - WhereMaskSet *pMaskSet; /* The expression mask set */ - WhereLevel *pLevel; /* A single level in pWInfo->a[] */ - WhereLoop *pLoop; /* Pointer to a single WhereLoop object */ - int ii; /* Loop counter */ - sqlite3 *db; /* Database connection */ - int rc; /* Return code */ - - assert( (wctrlFlags & WHERE_ONEPASS_MULTIROW)==0 || ( - (wctrlFlags & WHERE_ONEPASS_DESIRED)!=0 - && (wctrlFlags & WHERE_OMIT_OPEN_CLOSE)==0 - )); - - /* 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 - ** sqlite3_test_ctrl(SQLITE_TESTCTRL_OPTIMIZATIONS,...) */ - if( OptimizationDisabled(db, SQLITE_DistinctOpt) ){ - wctrlFlags &= ~WHERE_WANT_DISTINCT; - } - - /* The number of tables in the FROM clause is limited by the number of - ** bits in a Bitmask - */ - testcase( pTabList->nSrc==BMS ); - if( pTabList->nSrc>BMS ){ - sqlite3ErrorMsg(pParse, "at most %d tables in a join", BMS); - return 0; - } - - /* This function normally generates a nested loop for all tables in - ** pTabList. But if the WHERE_ONETABLE_ONLY flag is set, then we should - ** only generate code for the first table in pTabList and assume that - ** any cursors associated with subsequent tables are uninitialized. - */ - nTabList = (wctrlFlags & WHERE_ONETABLE_ONLY) ? 1 : pTabList->nSrc; - - /* Allocate and initialize the WhereInfo structure that will become the - ** return value. A single allocation is used to store the WhereInfo - ** struct, the contents of WhereInfo.a[], the WhereClause structure - ** and the WhereMaskSet structure. Since WhereClause contains an 8-byte - ** field (type Bitmask) it must be aligned on an 8-byte boundary on - ** some architectures. Hence the ROUND8() below. - */ - nByteWInfo = ROUND8(sizeof(WhereInfo)+(nTabList-1)*sizeof(WhereLevel)); - pWInfo = sqlite3DbMallocZero(db, nByteWInfo + sizeof(WhereLoop)); - if( db->mallocFailed ){ - sqlite3DbFree(db, pWInfo); - pWInfo = 0; - goto whereBeginError; - } - pWInfo->aiCurOnePass[0] = pWInfo->aiCurOnePass[1] = -1; - pWInfo->nLevel = nTabList; - pWInfo->pParse = pParse; - pWInfo->pTabList = pTabList; - pWInfo->pOrderBy = pOrderBy; - pWInfo->pResultSet = pResultSet; - pWInfo->iBreak = pWInfo->iContinue = sqlite3VdbeMakeLabel(v); - pWInfo->wctrlFlags = wctrlFlags; - pWInfo->savedNQueryLoop = pParse->nQueryLoop; - assert( pWInfo->eOnePass==ONEPASS_OFF ); /* ONEPASS defaults to OFF */ - pMaskSet = &pWInfo->sMaskSet; - sWLB.pWInfo = pWInfo; - sWLB.pWC = &pWInfo->sWC; - sWLB.pNew = (WhereLoop*)(((char*)pWInfo)+nByteWInfo); - assert( EIGHT_BYTE_ALIGNMENT(sWLB.pNew) ); - whereLoopInit(sWLB.pNew); -#ifdef SQLITE_DEBUG - sWLB.pNew->cId = '*'; -#endif - - /* Split the WHERE clause into separate subexpressions where each - ** subexpression is separated by an AND operator. - */ - initMaskSet(pMaskSet); - sqlite3WhereClauseInit(&pWInfo->sWC, pWInfo); - sqlite3WhereSplit(&pWInfo->sWC, pWhere, TK_AND); - - /* Special case: a WHERE clause that is constant. Evaluate the - ** expression and either jump over all of the code or fall thru. - */ - for(ii=0; ii<sWLB.pWC->nTerm; ii++){ - if( nTabList==0 || sqlite3ExprIsConstantNotJoin(sWLB.pWC->a[ii].pExpr) ){ - sqlite3ExprIfFalse(pParse, sWLB.pWC->a[ii].pExpr, pWInfo->iBreak, - SQLITE_JUMPIFNULL); - sWLB.pWC->a[ii].wtFlags |= TERM_CODED; - } - } - - /* Special case: No FROM clause - */ - if( nTabList==0 ){ - if( pOrderBy ) pWInfo->nOBSat = pOrderBy->nExpr; - if( wctrlFlags & WHERE_WANT_DISTINCT ){ - pWInfo->eDistinct = WHERE_DISTINCT_UNIQUE; - } - } - - /* Assign a bit from the bitmask to every term in the FROM clause. - ** - ** The N-th term of the FROM clause is assigned a bitmask of 1<<N. - ** - ** The rule of the previous sentence ensures thta if X is the bitmask for - ** a table T, then X-1 is the bitmask for all other tables to the left of T. - ** Knowing the bitmask for all tables to the left of a left join is - ** important. Ticket #3015. - ** - ** Note that bitmasks are created for all pTabList->nSrc tables in - ** pTabList, not just the first nTabList tables. nTabList is normally - ** equal to pTabList->nSrc but might be shortened to 1 if the - ** WHERE_ONETABLE_ONLY flag is set. - */ - for(ii=0; ii<pTabList->nSrc; ii++){ - createMask(pMaskSet, pTabList->a[ii].iCursor); - sqlite3WhereTabFuncArgs(pParse, &pTabList->a[ii], &pWInfo->sWC); - } -#ifdef SQLITE_DEBUG - for(ii=0; ii<pTabList->nSrc; ii++){ - Bitmask m = sqlite3WhereGetMask(pMaskSet, pTabList->a[ii].iCursor); - assert( m==MASKBIT(ii) ); - } -#endif - - /* Analyze all of the subexpressions. */ - sqlite3WhereExprAnalyze(pTabList, &pWInfo->sWC); - if( db->mallocFailed ) goto whereBeginError; - - if( wctrlFlags & WHERE_WANT_DISTINCT ){ - if( isDistinctRedundant(pParse, pTabList, &pWInfo->sWC, pResultSet) ){ - /* The DISTINCT marking is pointless. Ignore it. */ - pWInfo->eDistinct = WHERE_DISTINCT_UNIQUE; - }else if( pOrderBy==0 ){ - /* Try to ORDER BY the result set to make distinct processing easier */ - pWInfo->wctrlFlags |= WHERE_DISTINCTBY; - pWInfo->pOrderBy = pResultSet; - } - } - - /* Construct the WhereLoop objects */ - WHERETRACE(0xffff,("*** Optimizer Start *** (wctrlFlags: 0x%x)\n", - wctrlFlags)); -#if defined(WHERETRACE_ENABLED) - if( sqlite3WhereTrace & 0x100 ){ /* Display all terms of the WHERE clause */ - int i; - for(i=0; i<sWLB.pWC->nTerm; i++){ - whereTermPrint(&sWLB.pWC->a[i], i); - } - } -#endif - - if( nTabList!=1 || whereShortCut(&sWLB)==0 ){ - rc = whereLoopAddAll(&sWLB); - if( rc ) goto whereBeginError; - -#ifdef WHERETRACE_ENABLED - if( sqlite3WhereTrace ){ /* Display all of the WhereLoop objects */ - WhereLoop *p; - int i; - static const char zLabel[] = "0123456789abcdefghijklmnopqrstuvwyxz" - "ABCDEFGHIJKLMNOPQRSTUVWYXZ"; - for(p=pWInfo->pLoops, i=0; p; p=p->pNextLoop, i++){ - p->cId = zLabel[i%sizeof(zLabel)]; - whereLoopPrint(p, sWLB.pWC); - } - } -#endif - - wherePathSolver(pWInfo, 0); - if( db->mallocFailed ) goto whereBeginError; - if( pWInfo->pOrderBy ){ - wherePathSolver(pWInfo, pWInfo->nRowOut+1); - if( db->mallocFailed ) goto whereBeginError; - } - } - if( pWInfo->pOrderBy==0 && (db->flags & SQLITE_ReverseOrder)!=0 ){ - pWInfo->revMask = (Bitmask)(-1); - } - if( pParse->nErr || NEVER(db->mallocFailed) ){ - goto whereBeginError; - } -#ifdef WHERETRACE_ENABLED - if( sqlite3WhereTrace ){ - sqlite3DebugPrintf("---- Solution nRow=%d", pWInfo->nRowOut); - if( pWInfo->nOBSat>0 ){ - sqlite3DebugPrintf(" ORDERBY=%d,0x%llx", pWInfo->nOBSat, pWInfo->revMask); - } - switch( pWInfo->eDistinct ){ - case WHERE_DISTINCT_UNIQUE: { - sqlite3DebugPrintf(" DISTINCT=unique"); - break; - } - case WHERE_DISTINCT_ORDERED: { - sqlite3DebugPrintf(" DISTINCT=ordered"); - break; - } - case WHERE_DISTINCT_UNORDERED: { - sqlite3DebugPrintf(" DISTINCT=unordered"); - break; - } - } - sqlite3DebugPrintf("\n"); - for(ii=0; ii<pWInfo->nLevel; ii++){ - whereLoopPrint(pWInfo->a[ii].pWLoop, sWLB.pWC); - } - } -#endif - /* Attempt to omit tables from the join that do not effect the result */ - if( pWInfo->nLevel>=2 - && pResultSet!=0 - && OptimizationEnabled(db, SQLITE_OmitNoopJoin) - ){ - Bitmask tabUsed = sqlite3WhereExprListUsage(pMaskSet, pResultSet); - if( sWLB.pOrderBy ){ - tabUsed |= sqlite3WhereExprListUsage(pMaskSet, sWLB.pOrderBy); - } - while( pWInfo->nLevel>=2 ){ - WhereTerm *pTerm, *pEnd; - pLoop = pWInfo->a[pWInfo->nLevel-1].pWLoop; - if( (pWInfo->pTabList->a[pLoop->iTab].fg.jointype & JT_LEFT)==0 ) break; - if( (wctrlFlags & WHERE_WANT_DISTINCT)==0 - && (pLoop->wsFlags & WHERE_ONEROW)==0 - ){ - break; - } - if( (tabUsed & pLoop->maskSelf)!=0 ) break; - pEnd = sWLB.pWC->a + sWLB.pWC->nTerm; - for(pTerm=sWLB.pWC->a; pTerm<pEnd; pTerm++){ - if( (pTerm->prereqAll & pLoop->maskSelf)!=0 - && !ExprHasProperty(pTerm->pExpr, EP_FromJoin) - ){ - break; - } - } - if( pTerm<pEnd ) break; - WHERETRACE(0xffff, ("-> drop loop %c not used\n", pLoop->cId)); - pWInfo->nLevel--; - nTabList--; - } - } - WHERETRACE(0xffff,("*** Optimizer Finished ***\n")); - pWInfo->pParse->nQueryLoop += pWInfo->nRowOut; - - /* If the caller is an UPDATE or DELETE statement that is requesting - ** to use a one-pass algorithm, determine if this is appropriate. - ** The one-pass algorithm only works if the WHERE clause constrains - ** the statement to update or delete a single row. - */ - assert( (wctrlFlags & WHERE_ONEPASS_DESIRED)==0 || pWInfo->nLevel==1 ); - if( (wctrlFlags & WHERE_ONEPASS_DESIRED)!=0 ){ - int wsFlags = pWInfo->a[0].pWLoop->wsFlags; - int bOnerow = (wsFlags & WHERE_ONEROW)!=0; - if( bOnerow || ( (wctrlFlags & WHERE_ONEPASS_MULTIROW) - && 0==(wsFlags & WHERE_VIRTUALTABLE) - )){ - pWInfo->eOnePass = bOnerow ? ONEPASS_SINGLE : ONEPASS_MULTI; - if( HasRowid(pTabList->a[0].pTab) ){ - pWInfo->a[0].pWLoop->wsFlags &= ~WHERE_IDX_ONLY; - } - } - } - - /* Open all tables in the pTabList and any indices selected for - ** searching those tables. - */ - for(ii=0, pLevel=pWInfo->a; ii<nTabList; ii++, pLevel++){ - Table *pTab; /* Table to open */ - int iDb; /* Index of database containing table/index */ - struct SrcList_item *pTabItem; - - pTabItem = &pTabList->a[pLevel->iFrom]; - pTab = pTabItem->pTab; - iDb = sqlite3SchemaToIndex(db, pTab->pSchema); - pLoop = pLevel->pWLoop; - if( (pTab->tabFlags & TF_Ephemeral)!=0 || pTab->pSelect ){ - /* Do nothing */ - }else -#ifndef SQLITE_OMIT_VIRTUALTABLE - if( (pLoop->wsFlags & WHERE_VIRTUALTABLE)!=0 ){ - const char *pVTab = (const char *)sqlite3GetVTable(db, pTab); - int iCur = pTabItem->iCursor; - sqlite3VdbeAddOp4(v, OP_VOpen, iCur, 0, 0, pVTab, P4_VTAB); - }else if( IsVirtual(pTab) ){ - /* noop */ - }else -#endif - if( (pLoop->wsFlags & WHERE_IDX_ONLY)==0 - && (wctrlFlags & WHERE_OMIT_OPEN_CLOSE)==0 ){ - int op = OP_OpenRead; - if( pWInfo->eOnePass!=ONEPASS_OFF ){ - op = OP_OpenWrite; - pWInfo->aiCurOnePass[0] = pTabItem->iCursor; - }; - sqlite3OpenTable(pParse, pTabItem->iCursor, iDb, pTab, op); - assert( pTabItem->iCursor==pLevel->iTabCur ); - testcase( pWInfo->eOnePass==ONEPASS_OFF && pTab->nCol==BMS-1 ); - testcase( pWInfo->eOnePass==ONEPASS_OFF && pTab->nCol==BMS ); - if( pWInfo->eOnePass==ONEPASS_OFF && pTab->nCol<BMS && HasRowid(pTab) ){ - Bitmask b = pTabItem->colUsed; - int n = 0; - for(; b; b=b>>1, n++){} - sqlite3VdbeChangeP4(v, sqlite3VdbeCurrentAddr(v)-1, - SQLITE_INT_TO_PTR(n), P4_INT32); - assert( n<=pTab->nCol ); - } -#ifdef SQLITE_ENABLE_COLUMN_USED_MASK - sqlite3VdbeAddOp4Dup8(v, OP_ColumnsUsed, pTabItem->iCursor, 0, 0, - (const u8*)&pTabItem->colUsed, P4_INT64); -#endif - }else{ - sqlite3TableLock(pParse, iDb, pTab->tnum, 0, pTab->zName); - } - if( pLoop->wsFlags & WHERE_INDEXED ){ - Index *pIx = pLoop->u.btree.pIndex; - int iIndexCur; - 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( !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->eOnePass!=ONEPASS_OFF ){ - Index *pJ = pTabItem->pTab->pIndex; - iIndexCur = iIdxCur; - assert( wctrlFlags & WHERE_ONEPASS_DESIRED ); - while( ALWAYS(pJ) && pJ!=pIx ){ - iIndexCur++; - pJ = pJ->pNext; - } - op = OP_OpenWrite; - 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 ); - if( op ){ - sqlite3VdbeAddOp3(v, op, iIndexCur, pIx->tnum, iDb); - sqlite3VdbeSetP4KeyInfo(pParse, pIx); - if( (pLoop->wsFlags & WHERE_CONSTRAINT)!=0 - && (pLoop->wsFlags & (WHERE_COLUMN_RANGE|WHERE_SKIPSCAN))==0 - && (pWInfo->wctrlFlags&WHERE_ORDERBY_MIN)==0 - ){ - sqlite3VdbeChangeP5(v, OPFLAG_SEEKEQ); /* Hint to COMDB2 */ - } - VdbeComment((v, "%s", pIx->zName)); -#ifdef SQLITE_ENABLE_COLUMN_USED_MASK - { - u64 colUsed = 0; - int ii, jj; - for(ii=0; ii<pIx->nColumn; ii++){ - jj = pIx->aiColumn[ii]; - if( jj<0 ) continue; - if( jj>63 ) jj = 63; - if( (pTabItem->colUsed & MASKBIT(jj))==0 ) continue; - colUsed |= ((u64)1)<<(ii<63 ? ii : 63); - } - sqlite3VdbeAddOp4Dup8(v, OP_ColumnsUsed, iIndexCur, 0, 0, - (u8*)&colUsed, P4_INT64); - } -#endif /* SQLITE_ENABLE_COLUMN_USED_MASK */ - } - } - if( iDb>=0 ) sqlite3CodeVerifySchema(pParse, iDb); - } - pWInfo->iTop = sqlite3VdbeCurrentAddr(v); - if( db->mallocFailed ) goto whereBeginError; - - /* Generate the code to do the search. Each iteration of the for - ** loop below generates code for a single nested loop of the VM - ** program. - */ - 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, - &pTabList->a[pLevel->iFrom], notReady, pLevel); - if( db->mallocFailed ) goto whereBeginError; - } -#endif - addrExplain = sqlite3WhereExplainOneScan( - pParse, pTabList, pLevel, ii, pLevel->iFrom, wctrlFlags - ); - pLevel->addrBody = sqlite3VdbeCurrentAddr(v); - notReady = sqlite3WhereCodeOneLoopStart(pWInfo, ii, notReady); - pWInfo->iContinue = pLevel->addrCont; - if( (wsFlags&WHERE_MULTI_OR)==0 && (wctrlFlags&WHERE_ONETABLE_ONLY)==0 ){ - sqlite3WhereAddScanStatus(v, pTabList, pLevel, addrExplain); - } - } - - /* Done. */ - VdbeModuleComment((v, "Begin WHERE-core")); - return pWInfo; - - /* Jump here if malloc fails */ -whereBeginError: - if( pWInfo ){ - pParse->nQueryLoop = pWInfo->savedNQueryLoop; - whereInfoFree(db, pWInfo); - } - return 0; -} - -/* -** Generate the end of the WHERE loop. See comments on -** sqlite3WhereBegin() for additional information. -*/ -void sqlite3WhereEnd(WhereInfo *pWInfo){ - Parse *pParse = pWInfo->pParse; - Vdbe *v = pParse->pVdbe; - int i; - WhereLevel *pLevel; - WhereLoop *pLoop; - SrcList *pTabList = pWInfo->pTabList; - sqlite3 *db = pParse->db; - - /* Generate loop termination code. - */ - VdbeModuleComment((v, "End WHERE-core")); - sqlite3ExprCacheClear(pParse); - for(i=pWInfo->nLevel-1; i>=0; i--){ - int addr; - pLevel = &pWInfo->a[i]; - pLoop = pLevel->pWLoop; - sqlite3VdbeResolveLabel(v, pLevel->addrCont); - if( pLevel->op!=OP_Noop ){ - sqlite3VdbeAddOp3(v, pLevel->op, pLevel->p1, pLevel->p2, pLevel->p3); - sqlite3VdbeChangeP5(v, pLevel->p5); - VdbeCoverage(v); - VdbeCoverageIf(v, pLevel->op==OP_Next); - VdbeCoverageIf(v, pLevel->op==OP_Prev); - VdbeCoverageIf(v, pLevel->op==OP_VNext); - } - if( pLoop->wsFlags & WHERE_IN_ABLE && pLevel->u.in.nIn>0 ){ - struct InLoop *pIn; - int j; - sqlite3VdbeResolveLabel(v, pLevel->addrNxt); - for(j=pLevel->u.in.nIn, pIn=&pLevel->u.in.aInLoop[j-1]; j>0; j--, pIn--){ - sqlite3VdbeJumpHere(v, pIn->addrInTop+1); - sqlite3VdbeAddOp2(v, pIn->eEndLoopOp, pIn->iCur, pIn->addrInTop); - VdbeCoverage(v); - VdbeCoverageIf(v, pIn->eEndLoopOp==OP_PrevIfOpen); - VdbeCoverageIf(v, pIn->eEndLoopOp==OP_NextIfOpen); - sqlite3VdbeJumpHere(v, pIn->addrInTop-1); - } - } - sqlite3VdbeResolveLabel(v, pLevel->addrBrk); - if( pLevel->addrSkip ){ - sqlite3VdbeGoto(v, pLevel->addrSkip); - VdbeComment((v, "next skip-scan on %s", pLoop->u.btree.pIndex->zName)); - sqlite3VdbeJumpHere(v, pLevel->addrSkip); - sqlite3VdbeJumpHere(v, pLevel->addrSkip-2); - } - if( pLevel->addrLikeRep ){ - int op; - if( sqlite3VdbeGetOp(v, pLevel->addrLikeRep-1)->p1 ){ - op = OP_DecrJumpZero; - }else{ - op = OP_JumpZeroIncr; - } - sqlite3VdbeAddOp2(v, op, pLevel->iLikeRepCntr, pLevel->addrLikeRep); - VdbeCoverage(v); - } - if( pLevel->iLeftJoin ){ - addr = sqlite3VdbeAddOp1(v, OP_IfPos, pLevel->iLeftJoin); VdbeCoverage(v); - assert( (pLoop->wsFlags & WHERE_IDX_ONLY)==0 - || (pLoop->wsFlags & WHERE_INDEXED)!=0 ); - if( (pLoop->wsFlags & WHERE_IDX_ONLY)==0 ){ - sqlite3VdbeAddOp1(v, OP_NullRow, pTabList->a[i].iCursor); - } - if( pLoop->wsFlags & WHERE_INDEXED ){ - sqlite3VdbeAddOp1(v, OP_NullRow, pLevel->iIdxCur); - } - if( pLevel->op==OP_Return ){ - sqlite3VdbeAddOp2(v, OP_Gosub, pLevel->p1, pLevel->addrFirst); - }else{ - sqlite3VdbeGoto(v, pLevel->addrFirst); - } - sqlite3VdbeJumpHere(v, addr); - } - VdbeModuleComment((v, "End WHERE-loop%d: %s", i, - pWInfo->pTabList->a[pLevel->iFrom].pTab->zName)); - } - - /* The "break" point is here, just past the end of the outer loop. - ** Set it. - */ - sqlite3VdbeResolveLabel(v, pWInfo->iBreak); - - assert( pWInfo->nLevel<=pTabList->nSrc ); - for(i=0, pLevel=pWInfo->a; i<pWInfo->nLevel; i++, pLevel++){ - int k, last; - VdbeOp *pOp; - Index *pIdx = 0; - struct SrcList_item *pTabItem = &pTabList->a[pLevel->iFrom]; - Table *pTab = pTabItem->pTab; - assert( pTab!=0 ); - pLoop = pLevel->pWLoop; - - /* For a co-routine, change all OP_Column references to the table of - ** the co-routine into OP_Copy of result contained in a register. - ** OP_Rowid becomes OP_Null. - */ - if( pTabItem->fg.viaCoroutine && !db->mallocFailed ){ - translateColumnToCopy(v, pLevel->addrBody, pLevel->iTabCur, - pTabItem->regResult, 0); - continue; - } - - /* Close all of the cursors that were opened by sqlite3WhereBegin. - ** Except, do not close cursors that will be reused by the OR optimization - ** (WHERE_OMIT_OPEN_CLOSE). And do not close the OP_OpenWrite cursors - ** created for the ONEPASS optimization. - */ - if( (pTab->tabFlags & TF_Ephemeral)==0 - && pTab->pSelect==0 - && (pWInfo->wctrlFlags & WHERE_OMIT_OPEN_CLOSE)==0 - ){ - int ws = pLoop->wsFlags; - if( pWInfo->eOnePass==ONEPASS_OFF && (ws & WHERE_IDX_ONLY)==0 ){ - sqlite3VdbeAddOp1(v, OP_Close, pTabItem->iCursor); - } - if( (ws & WHERE_INDEXED)!=0 - && (ws & (WHERE_IPK|WHERE_AUTO_INDEX))==0 - && pLevel->iIdxCur!=pWInfo->aiCurOnePass[1] - ){ - sqlite3VdbeAddOp1(v, OP_Close, pLevel->iIdxCur); - } - } - - /* If this scan uses an index, make VDBE code substitutions to read data - ** from the index instead of from the table where possible. In some cases - ** this optimization prevents the table from ever being read, which can - ** yield a significant performance boost. - ** - ** Calls to the code generator in between sqlite3WhereBegin and - ** sqlite3WhereEnd will have created code that references the table - ** directly. This loop scans all that code looking for opcodes - ** that reference the table and converts them into opcodes that - ** reference the index. - */ - if( pLoop->wsFlags & (WHERE_INDEXED|WHERE_IDX_ONLY) ){ - pIdx = pLoop->u.btree.pIndex; - }else if( pLoop->wsFlags & WHERE_MULTI_OR ){ - pIdx = pLevel->u.pCovidx; - } - if( pIdx - && (pWInfo->eOnePass==ONEPASS_OFF || !HasRowid(pIdx->pTable)) - && !db->mallocFailed - ){ - last = sqlite3VdbeCurrentAddr(v); - k = pLevel->addrBody; - pOp = sqlite3VdbeGetOp(v, k); - for(; k<last; k++, pOp++){ - if( pOp->p1!=pLevel->iTabCur ) continue; - if( pOp->opcode==OP_Column ){ - int x = pOp->p2; - assert( pIdx->pTable==pTab ); - if( !HasRowid(pTab) ){ - Index *pPk = sqlite3PrimaryKeyIndex(pTab); - x = pPk->aiColumn[x]; - assert( x>=0 ); - } - x = sqlite3ColumnOfIndex(pIdx, x); - if( x>=0 ){ - pOp->p2 = x; - pOp->p1 = pLevel->iIdxCur; - } - assert( (pLoop->wsFlags & WHERE_IDX_ONLY)==0 || x>=0 ); - }else if( pOp->opcode==OP_Rowid ){ - pOp->p1 = pLevel->iIdxCur; - pOp->opcode = OP_IdxRowid; - } - } - } - } - - /* Final cleanup - */ - pParse->nQueryLoop = pWInfo->savedNQueryLoop; - whereInfoFree(db, pWInfo); - return; -} |