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Diffstat (limited to 'chromium/third_party/sqlite/sqlite-src-3240000/src/whereexpr.c')
| -rw-r--r-- | chromium/third_party/sqlite/sqlite-src-3240000/src/whereexpr.c | 1531 |
1 files changed, 0 insertions, 1531 deletions
diff --git a/chromium/third_party/sqlite/sqlite-src-3240000/src/whereexpr.c b/chromium/third_party/sqlite/sqlite-src-3240000/src/whereexpr.c deleted file mode 100644 index 29750080a12..00000000000 --- a/chromium/third_party/sqlite/sqlite-src-3240000/src/whereexpr.c +++ /dev/null @@ -1,1531 +0,0 @@ -/* -** 2015-06-08 -** -** 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 file was originally part of where.c but was split out to improve -** readability and editabiliity. This file contains utility routines for -** analyzing Expr objects in the WHERE clause. -*/ -#include "sqliteInt.h" -#include "whereInt.h" - -/* Forward declarations */ -static void exprAnalyze(SrcList*, WhereClause*, int); - -/* -** Deallocate all memory associated with a WhereOrInfo object. -*/ -static void whereOrInfoDelete(sqlite3 *db, WhereOrInfo *p){ - sqlite3WhereClauseClear(&p->wc); - sqlite3DbFree(db, p); -} - -/* -** Deallocate all memory associated with a WhereAndInfo object. -*/ -static void whereAndInfoDelete(sqlite3 *db, WhereAndInfo *p){ - sqlite3WhereClauseClear(&p->wc); - sqlite3DbFree(db, p); -} - -/* -** Add a single new WhereTerm entry to the WhereClause object pWC. -** The new WhereTerm object is constructed from Expr p and with wtFlags. -** The index in pWC->a[] of the new WhereTerm is returned on success. -** 0 is returned if the new WhereTerm could not be added due to a memory -** allocation error. The memory allocation failure will be recorded in -** the db->mallocFailed flag so that higher-level functions can detect it. -** -** This routine will increase the size of the pWC->a[] array as necessary. -** -** If the wtFlags argument includes TERM_DYNAMIC, then responsibility -** for freeing the expression p is assumed by the WhereClause object pWC. -** This is true even if this routine fails to allocate a new WhereTerm. -** -** WARNING: This routine might reallocate the space used to store -** WhereTerms. All pointers to WhereTerms should be invalidated after -** calling this routine. Such pointers may be reinitialized by referencing -** the pWC->a[] array. -*/ -static int whereClauseInsert(WhereClause *pWC, Expr *p, u16 wtFlags){ - WhereTerm *pTerm; - int idx; - testcase( wtFlags & TERM_VIRTUAL ); - if( pWC->nTerm>=pWC->nSlot ){ - WhereTerm *pOld = pWC->a; - sqlite3 *db = pWC->pWInfo->pParse->db; - pWC->a = sqlite3DbMallocRawNN(db, sizeof(pWC->a[0])*pWC->nSlot*2 ); - if( pWC->a==0 ){ - if( wtFlags & TERM_DYNAMIC ){ - sqlite3ExprDelete(db, p); - } - pWC->a = pOld; - return 0; - } - memcpy(pWC->a, pOld, sizeof(pWC->a[0])*pWC->nTerm); - if( pOld!=pWC->aStatic ){ - sqlite3DbFree(db, pOld); - } - pWC->nSlot = sqlite3DbMallocSize(db, pWC->a)/sizeof(pWC->a[0]); - } - pTerm = &pWC->a[idx = pWC->nTerm++]; - if( p && ExprHasProperty(p, EP_Unlikely) ){ - pTerm->truthProb = sqlite3LogEst(p->iTable) - 270; - }else{ - pTerm->truthProb = 1; - } - pTerm->pExpr = sqlite3ExprSkipCollate(p); - pTerm->wtFlags = wtFlags; - pTerm->pWC = pWC; - pTerm->iParent = -1; - memset(&pTerm->eOperator, 0, - sizeof(WhereTerm) - offsetof(WhereTerm,eOperator)); - return idx; -} - -/* -** Return TRUE if the given operator is one of the operators that is -** allowed for an indexable WHERE clause term. The allowed operators are -** "=", "<", ">", "<=", ">=", "IN", "IS", and "IS NULL" -*/ -static int allowedOp(int op){ - assert( TK_GT>TK_EQ && TK_GT<TK_GE ); - assert( TK_LT>TK_EQ && TK_LT<TK_GE ); - assert( TK_LE>TK_EQ && TK_LE<TK_GE ); - assert( TK_GE==TK_EQ+4 ); - return op==TK_IN || (op>=TK_EQ && op<=TK_GE) || op==TK_ISNULL || op==TK_IS; -} - -/* -** Commute a comparison operator. Expressions of the form "X op Y" -** are converted into "Y op X". -** -** If left/right precedence rules come into play when determining the -** collating sequence, then COLLATE operators are adjusted to ensure -** that the collating sequence does not change. For example: -** "Y collate NOCASE op X" becomes "X op Y" because any collation sequence on -** the left hand side of a comparison overrides any collation sequence -** attached to the right. For the same reason the EP_Collate flag -** is not commuted. -*/ -static void exprCommute(Parse *pParse, Expr *pExpr){ - u16 expRight = (pExpr->pRight->flags & EP_Collate); - u16 expLeft = (pExpr->pLeft->flags & EP_Collate); - assert( allowedOp(pExpr->op) && pExpr->op!=TK_IN ); - if( expRight==expLeft ){ - /* Either X and Y both have COLLATE operator or neither do */ - if( expRight ){ - /* Both X and Y have COLLATE operators. Make sure X is always - ** used by clearing the EP_Collate flag from Y. */ - pExpr->pRight->flags &= ~EP_Collate; - }else if( sqlite3ExprCollSeq(pParse, pExpr->pLeft)!=0 ){ - /* Neither X nor Y have COLLATE operators, but X has a non-default - ** collating sequence. So add the EP_Collate marker on X to cause - ** it to be searched first. */ - pExpr->pLeft->flags |= EP_Collate; - } - } - SWAP(Expr*,pExpr->pRight,pExpr->pLeft); - if( pExpr->op>=TK_GT ){ - assert( TK_LT==TK_GT+2 ); - assert( TK_GE==TK_LE+2 ); - assert( TK_GT>TK_EQ ); - assert( TK_GT<TK_LE ); - assert( pExpr->op>=TK_GT && pExpr->op<=TK_GE ); - pExpr->op = ((pExpr->op-TK_GT)^2)+TK_GT; - } -} - -/* -** Translate from TK_xx operator to WO_xx bitmask. -*/ -static u16 operatorMask(int op){ - u16 c; - assert( allowedOp(op) ); - if( op==TK_IN ){ - c = WO_IN; - }else if( op==TK_ISNULL ){ - c = WO_ISNULL; - }else if( op==TK_IS ){ - c = WO_IS; - }else{ - assert( (WO_EQ<<(op-TK_EQ)) < 0x7fff ); - c = (u16)(WO_EQ<<(op-TK_EQ)); - } - assert( op!=TK_ISNULL || c==WO_ISNULL ); - assert( op!=TK_IN || c==WO_IN ); - assert( op!=TK_EQ || c==WO_EQ ); - assert( op!=TK_LT || c==WO_LT ); - assert( op!=TK_LE || c==WO_LE ); - assert( op!=TK_GT || c==WO_GT ); - assert( op!=TK_GE || c==WO_GE ); - assert( op!=TK_IS || c==WO_IS ); - return c; -} - - -#ifndef SQLITE_OMIT_LIKE_OPTIMIZATION -/* -** Check to see if the given expression is a LIKE or GLOB operator that -** can be optimized using inequality constraints. Return TRUE if it is -** so and false if not. -** -** In order for the operator to be optimizible, the RHS must be a string -** literal that does not begin with a wildcard. The LHS must be a column -** that may only be NULL, a string, or a BLOB, never a number. (This means -** that virtual tables cannot participate in the LIKE optimization.) The -** collating sequence for the column on the LHS must be appropriate for -** the operator. -*/ -static int isLikeOrGlob( - Parse *pParse, /* Parsing and code generating context */ - Expr *pExpr, /* Test this expression */ - Expr **ppPrefix, /* Pointer to TK_STRING expression with pattern prefix */ - int *pisComplete, /* True if the only wildcard is % in the last character */ - int *pnoCase /* True if uppercase is equivalent to lowercase */ -){ - const u8 *z = 0; /* String on RHS of LIKE operator */ - Expr *pRight, *pLeft; /* Right and left size of LIKE operator */ - ExprList *pList; /* List of operands to the LIKE operator */ - int c; /* One character in z[] */ - int cnt; /* Number of non-wildcard prefix characters */ - char wc[4]; /* Wildcard characters */ - sqlite3 *db = pParse->db; /* Database connection */ - sqlite3_value *pVal = 0; - int op; /* Opcode of pRight */ - int rc; /* Result code to return */ - - if( !sqlite3IsLikeFunction(db, pExpr, pnoCase, wc) ){ - return 0; - } -#ifdef SQLITE_EBCDIC - if( *pnoCase ) return 0; -#endif - pList = pExpr->x.pList; - pLeft = pList->a[1].pExpr; - - pRight = sqlite3ExprSkipCollate(pList->a[0].pExpr); - op = pRight->op; - if( op==TK_VARIABLE && (db->flags & SQLITE_EnableQPSG)==0 ){ - Vdbe *pReprepare = pParse->pReprepare; - int iCol = pRight->iColumn; - pVal = sqlite3VdbeGetBoundValue(pReprepare, iCol, SQLITE_AFF_BLOB); - if( pVal && sqlite3_value_type(pVal)==SQLITE_TEXT ){ - z = sqlite3_value_text(pVal); - } - sqlite3VdbeSetVarmask(pParse->pVdbe, iCol); - assert( pRight->op==TK_VARIABLE || pRight->op==TK_REGISTER ); - }else if( op==TK_STRING ){ - z = (u8*)pRight->u.zToken; - } - if( z ){ - - /* If the RHS begins with a digit or a minus sign, then the LHS must - ** be an ordinary column (not a virtual table column) with TEXT affinity. - ** Otherwise the LHS might be numeric and "lhs >= rhs" would be false - ** even though "lhs LIKE rhs" is true. But if the RHS does not start - ** with a digit or '-', then "lhs LIKE rhs" will always be false if - ** the LHS is numeric and so the optimization still works. - */ - if( sqlite3Isdigit(z[0]) || z[0]=='-' ){ - if( pLeft->op!=TK_COLUMN - || sqlite3ExprAffinity(pLeft)!=SQLITE_AFF_TEXT - || IsVirtual(pLeft->pTab) /* Value might be numeric */ - ){ - sqlite3ValueFree(pVal); - return 0; - } - } - - /* Count the number of prefix characters prior to the first wildcard */ - cnt = 0; - while( (c=z[cnt])!=0 && c!=wc[0] && c!=wc[1] && c!=wc[2] ){ - cnt++; - if( c==wc[3] && z[cnt]!=0 ) cnt++; - } - - /* The optimization is possible only if (1) the pattern does not begin - ** with a wildcard and if (2) the non-wildcard prefix does not end with - ** an (illegal 0xff) character. The second condition is necessary so - ** that we can increment the prefix key to find an upper bound for the - ** range search. - */ - if( cnt!=0 && 255!=(u8)z[cnt-1] ){ - Expr *pPrefix; - - /* A "complete" match if the pattern ends with "*" or "%" */ - *pisComplete = c==wc[0] && z[cnt+1]==0; - - /* Get the pattern prefix. Remove all escapes from the prefix. */ - pPrefix = sqlite3Expr(db, TK_STRING, (char*)z); - if( pPrefix ){ - int iFrom, iTo; - char *zNew = pPrefix->u.zToken; - zNew[cnt] = 0; - for(iFrom=iTo=0; iFrom<cnt; iFrom++){ - if( zNew[iFrom]==wc[3] ) iFrom++; - zNew[iTo++] = zNew[iFrom]; - } - zNew[iTo] = 0; - } - *ppPrefix = pPrefix; - - /* If the RHS pattern is a bound parameter, make arrangements to - ** reprepare the statement when that parameter is rebound */ - if( op==TK_VARIABLE ){ - Vdbe *v = pParse->pVdbe; - sqlite3VdbeSetVarmask(v, pRight->iColumn); - if( *pisComplete && pRight->u.zToken[1] ){ - /* If the rhs of the LIKE expression is a variable, and the current - ** value of the variable means there is no need to invoke the LIKE - ** function, then no OP_Variable will be added to the program. - ** This causes problems for the sqlite3_bind_parameter_name() - ** API. To work around them, add a dummy OP_Variable here. - */ - int r1 = sqlite3GetTempReg(pParse); - sqlite3ExprCodeTarget(pParse, pRight, r1); - sqlite3VdbeChangeP3(v, sqlite3VdbeCurrentAddr(v)-1, 0); - sqlite3ReleaseTempReg(pParse, r1); - } - } - }else{ - z = 0; - } - } - - rc = (z!=0); - sqlite3ValueFree(pVal); - return rc; -} -#endif /* SQLITE_OMIT_LIKE_OPTIMIZATION */ - - -#ifndef SQLITE_OMIT_VIRTUALTABLE -/* -** Check to see if the pExpr expression is a form that needs to be passed -** to the xBestIndex method of virtual tables. Forms of interest include: -** -** Expression Virtual Table Operator -** ----------------------- --------------------------------- -** 1. column MATCH expr SQLITE_INDEX_CONSTRAINT_MATCH -** 2. column GLOB expr SQLITE_INDEX_CONSTRAINT_GLOB -** 3. column LIKE expr SQLITE_INDEX_CONSTRAINT_LIKE -** 4. column REGEXP expr SQLITE_INDEX_CONSTRAINT_REGEXP -** 5. column != expr SQLITE_INDEX_CONSTRAINT_NE -** 6. expr != column SQLITE_INDEX_CONSTRAINT_NE -** 7. column IS NOT expr SQLITE_INDEX_CONSTRAINT_ISNOT -** 8. expr IS NOT column SQLITE_INDEX_CONSTRAINT_ISNOT -** 9. column IS NOT NULL SQLITE_INDEX_CONSTRAINT_ISNOTNULL -** -** In every case, "column" must be a column of a virtual table. If there -** is a match, set *ppLeft to the "column" expression, set *ppRight to the -** "expr" expression (even though in forms (6) and (8) the column is on the -** right and the expression is on the left). Also set *peOp2 to the -** appropriate virtual table operator. The return value is 1 or 2 if there -** is a match. The usual return is 1, but if the RHS is also a column -** of virtual table in forms (5) or (7) then return 2. -** -** If the expression matches none of the patterns above, return 0. -*/ -static int isAuxiliaryVtabOperator( - Expr *pExpr, /* Test this expression */ - unsigned char *peOp2, /* OUT: 0 for MATCH, or else an op2 value */ - Expr **ppLeft, /* Column expression to left of MATCH/op2 */ - Expr **ppRight /* Expression to left of MATCH/op2 */ -){ - if( pExpr->op==TK_FUNCTION ){ - static const struct Op2 { - const char *zOp; - unsigned char eOp2; - } aOp[] = { - { "match", SQLITE_INDEX_CONSTRAINT_MATCH }, - { "glob", SQLITE_INDEX_CONSTRAINT_GLOB }, - { "like", SQLITE_INDEX_CONSTRAINT_LIKE }, - { "regexp", SQLITE_INDEX_CONSTRAINT_REGEXP } - }; - ExprList *pList; - Expr *pCol; /* Column reference */ - int i; - - pList = pExpr->x.pList; - if( pList==0 || pList->nExpr!=2 ){ - return 0; - } - pCol = pList->a[1].pExpr; - if( pCol->op!=TK_COLUMN || !IsVirtual(pCol->pTab) ){ - return 0; - } - for(i=0; i<ArraySize(aOp); i++){ - if( sqlite3StrICmp(pExpr->u.zToken, aOp[i].zOp)==0 ){ - *peOp2 = aOp[i].eOp2; - *ppRight = pList->a[0].pExpr; - *ppLeft = pCol; - return 1; - } - } - }else if( pExpr->op==TK_NE || pExpr->op==TK_ISNOT || pExpr->op==TK_NOTNULL ){ - int res = 0; - Expr *pLeft = pExpr->pLeft; - Expr *pRight = pExpr->pRight; - if( pLeft->op==TK_COLUMN && IsVirtual(pLeft->pTab) ){ - res++; - } - if( pRight && pRight->op==TK_COLUMN && IsVirtual(pRight->pTab) ){ - res++; - SWAP(Expr*, pLeft, pRight); - } - *ppLeft = pLeft; - *ppRight = pRight; - if( pExpr->op==TK_NE ) *peOp2 = SQLITE_INDEX_CONSTRAINT_NE; - if( pExpr->op==TK_ISNOT ) *peOp2 = SQLITE_INDEX_CONSTRAINT_ISNOT; - if( pExpr->op==TK_NOTNULL ) *peOp2 = SQLITE_INDEX_CONSTRAINT_ISNOTNULL; - return res; - } - return 0; -} -#endif /* SQLITE_OMIT_VIRTUALTABLE */ - -/* -** If the pBase expression originated in the ON or USING clause of -** a join, then transfer the appropriate markings over to derived. -*/ -static void transferJoinMarkings(Expr *pDerived, Expr *pBase){ - if( pDerived ){ - pDerived->flags |= pBase->flags & EP_FromJoin; - pDerived->iRightJoinTable = pBase->iRightJoinTable; - } -} - -/* -** Mark term iChild as being a child of term iParent -*/ -static void markTermAsChild(WhereClause *pWC, int iChild, int iParent){ - pWC->a[iChild].iParent = iParent; - pWC->a[iChild].truthProb = pWC->a[iParent].truthProb; - pWC->a[iParent].nChild++; -} - -/* -** Return the N-th AND-connected subterm of pTerm. Or if pTerm is not -** a conjunction, then return just pTerm when N==0. If N is exceeds -** the number of available subterms, return NULL. -*/ -static WhereTerm *whereNthSubterm(WhereTerm *pTerm, int N){ - if( pTerm->eOperator!=WO_AND ){ - return N==0 ? pTerm : 0; - } - if( N<pTerm->u.pAndInfo->wc.nTerm ){ - return &pTerm->u.pAndInfo->wc.a[N]; - } - return 0; -} - -/* -** Subterms pOne and pTwo are contained within WHERE clause pWC. The -** two subterms are in disjunction - they are OR-ed together. -** -** If these two terms are both of the form: "A op B" with the same -** A and B values but different operators and if the operators are -** compatible (if one is = and the other is <, for example) then -** add a new virtual AND term to pWC that is the combination of the -** two. -** -** Some examples: -** -** x<y OR x=y --> x<=y -** x=y OR x=y --> x=y -** x<=y OR x<y --> x<=y -** -** The following is NOT generated: -** -** x<y OR x>y --> x!=y -*/ -static void whereCombineDisjuncts( - SrcList *pSrc, /* the FROM clause */ - WhereClause *pWC, /* The complete WHERE clause */ - WhereTerm *pOne, /* First disjunct */ - WhereTerm *pTwo /* Second disjunct */ -){ - u16 eOp = pOne->eOperator | pTwo->eOperator; - sqlite3 *db; /* Database connection (for malloc) */ - Expr *pNew; /* New virtual expression */ - int op; /* Operator for the combined expression */ - int idxNew; /* Index in pWC of the next virtual term */ - - if( (pOne->eOperator & (WO_EQ|WO_LT|WO_LE|WO_GT|WO_GE))==0 ) return; - if( (pTwo->eOperator & (WO_EQ|WO_LT|WO_LE|WO_GT|WO_GE))==0 ) return; - if( (eOp & (WO_EQ|WO_LT|WO_LE))!=eOp - && (eOp & (WO_EQ|WO_GT|WO_GE))!=eOp ) return; - assert( pOne->pExpr->pLeft!=0 && pOne->pExpr->pRight!=0 ); - assert( pTwo->pExpr->pLeft!=0 && pTwo->pExpr->pRight!=0 ); - if( sqlite3ExprCompare(0,pOne->pExpr->pLeft, pTwo->pExpr->pLeft, -1) ) return; - if( sqlite3ExprCompare(0,pOne->pExpr->pRight, pTwo->pExpr->pRight,-1) )return; - /* If we reach this point, it means the two subterms can be combined */ - if( (eOp & (eOp-1))!=0 ){ - if( eOp & (WO_LT|WO_LE) ){ - eOp = WO_LE; - }else{ - assert( eOp & (WO_GT|WO_GE) ); - eOp = WO_GE; - } - } - db = pWC->pWInfo->pParse->db; - pNew = sqlite3ExprDup(db, pOne->pExpr, 0); - if( pNew==0 ) return; - for(op=TK_EQ; eOp!=(WO_EQ<<(op-TK_EQ)); op++){ assert( op<TK_GE ); } - pNew->op = op; - idxNew = whereClauseInsert(pWC, pNew, TERM_VIRTUAL|TERM_DYNAMIC); - exprAnalyze(pSrc, pWC, idxNew); -} - -#if !defined(SQLITE_OMIT_OR_OPTIMIZATION) && !defined(SQLITE_OMIT_SUBQUERY) -/* -** Analyze a term that consists of two or more OR-connected -** subterms. So in: -** -** ... WHERE (a=5) AND (b=7 OR c=9 OR d=13) AND (d=13) -** ^^^^^^^^^^^^^^^^^^^^ -** -** This routine analyzes terms such as the middle term in the above example. -** A WhereOrTerm object is computed and attached to the term under -** analysis, regardless of the outcome of the analysis. Hence: -** -** WhereTerm.wtFlags |= TERM_ORINFO -** WhereTerm.u.pOrInfo = a dynamically allocated WhereOrTerm object -** -** The term being analyzed must have two or more of OR-connected subterms. -** A single subterm might be a set of AND-connected sub-subterms. -** Examples of terms under analysis: -** -** (A) t1.x=t2.y OR t1.x=t2.z OR t1.y=15 OR t1.z=t3.a+5 -** (B) x=expr1 OR expr2=x OR x=expr3 -** (C) t1.x=t2.y OR (t1.x=t2.z AND t1.y=15) -** (D) x=expr1 OR (y>11 AND y<22 AND z LIKE '*hello*') -** (E) (p.a=1 AND q.b=2 AND r.c=3) OR (p.x=4 AND q.y=5 AND r.z=6) -** (F) x>A OR (x=A AND y>=B) -** -** CASE 1: -** -** If all subterms are of the form T.C=expr for some single column of C and -** a single table T (as shown in example B above) then create a new virtual -** term that is an equivalent IN expression. In other words, if the term -** being analyzed is: -** -** x = expr1 OR expr2 = x OR x = expr3 -** -** then create a new virtual term like this: -** -** x IN (expr1,expr2,expr3) -** -** CASE 2: -** -** If there are exactly two disjuncts and one side has x>A and the other side -** has x=A (for the same x and A) then add a new virtual conjunct term to the -** WHERE clause of the form "x>=A". Example: -** -** x>A OR (x=A AND y>B) adds: x>=A -** -** The added conjunct can sometimes be helpful in query planning. -** -** CASE 3: -** -** If all subterms are indexable by a single table T, then set -** -** WhereTerm.eOperator = WO_OR -** WhereTerm.u.pOrInfo->indexable |= the cursor number for table T -** -** A subterm is "indexable" if it is of the form -** "T.C <op> <expr>" where C is any column of table T and -** <op> is one of "=", "<", "<=", ">", ">=", "IS NULL", or "IN". -** A subterm is also indexable if it is an AND of two or more -** subsubterms at least one of which is indexable. Indexable AND -** subterms have their eOperator set to WO_AND and they have -** u.pAndInfo set to a dynamically allocated WhereAndTerm object. -** -** From another point of view, "indexable" means that the subterm could -** potentially be used with an index if an appropriate index exists. -** This analysis does not consider whether or not the index exists; that -** is decided elsewhere. This analysis only looks at whether subterms -** appropriate for indexing exist. -** -** All examples A through E above satisfy case 3. But if a term -** also satisfies case 1 (such as B) we know that the optimizer will -** always prefer case 1, so in that case we pretend that case 3 is not -** satisfied. -** -** It might be the case that multiple tables are indexable. For example, -** (E) above is indexable on tables P, Q, and R. -** -** Terms that satisfy case 3 are candidates for lookup by using -** separate indices to find rowids for each subterm and composing -** the union of all rowids using a RowSet object. This is similar -** to "bitmap indices" in other database engines. -** -** OTHERWISE: -** -** If none of cases 1, 2, or 3 apply, then leave the eOperator set to -** zero. This term is not useful for search. -*/ -static void exprAnalyzeOrTerm( - SrcList *pSrc, /* the FROM clause */ - WhereClause *pWC, /* the complete WHERE clause */ - int idxTerm /* Index of the OR-term to be analyzed */ -){ - WhereInfo *pWInfo = pWC->pWInfo; /* WHERE clause processing context */ - Parse *pParse = pWInfo->pParse; /* Parser context */ - sqlite3 *db = pParse->db; /* Database connection */ - WhereTerm *pTerm = &pWC->a[idxTerm]; /* The term to be analyzed */ - Expr *pExpr = pTerm->pExpr; /* The expression of the term */ - int i; /* Loop counters */ - WhereClause *pOrWc; /* Breakup of pTerm into subterms */ - WhereTerm *pOrTerm; /* A Sub-term within the pOrWc */ - WhereOrInfo *pOrInfo; /* Additional information associated with pTerm */ - Bitmask chngToIN; /* Tables that might satisfy case 1 */ - Bitmask indexable; /* Tables that are indexable, satisfying case 2 */ - - /* - ** Break the OR clause into its separate subterms. The subterms are - ** stored in a WhereClause structure containing within the WhereOrInfo - ** object that is attached to the original OR clause term. - */ - assert( (pTerm->wtFlags & (TERM_DYNAMIC|TERM_ORINFO|TERM_ANDINFO))==0 ); - assert( pExpr->op==TK_OR ); - pTerm->u.pOrInfo = pOrInfo = sqlite3DbMallocZero(db, sizeof(*pOrInfo)); - if( pOrInfo==0 ) return; - pTerm->wtFlags |= TERM_ORINFO; - pOrWc = &pOrInfo->wc; - memset(pOrWc->aStatic, 0, sizeof(pOrWc->aStatic)); - sqlite3WhereClauseInit(pOrWc, pWInfo); - sqlite3WhereSplit(pOrWc, pExpr, TK_OR); - sqlite3WhereExprAnalyze(pSrc, pOrWc); - if( db->mallocFailed ) return; - assert( pOrWc->nTerm>=2 ); - - /* - ** Compute the set of tables that might satisfy cases 1 or 3. - */ - indexable = ~(Bitmask)0; - chngToIN = ~(Bitmask)0; - for(i=pOrWc->nTerm-1, pOrTerm=pOrWc->a; i>=0 && indexable; i--, pOrTerm++){ - if( (pOrTerm->eOperator & WO_SINGLE)==0 ){ - WhereAndInfo *pAndInfo; - assert( (pOrTerm->wtFlags & (TERM_ANDINFO|TERM_ORINFO))==0 ); - chngToIN = 0; - pAndInfo = sqlite3DbMallocRawNN(db, sizeof(*pAndInfo)); - if( pAndInfo ){ - WhereClause *pAndWC; - WhereTerm *pAndTerm; - int j; - Bitmask b = 0; - pOrTerm->u.pAndInfo = pAndInfo; - pOrTerm->wtFlags |= TERM_ANDINFO; - pOrTerm->eOperator = WO_AND; - pAndWC = &pAndInfo->wc; - memset(pAndWC->aStatic, 0, sizeof(pAndWC->aStatic)); - sqlite3WhereClauseInit(pAndWC, pWC->pWInfo); - sqlite3WhereSplit(pAndWC, pOrTerm->pExpr, TK_AND); - sqlite3WhereExprAnalyze(pSrc, pAndWC); - pAndWC->pOuter = pWC; - if( !db->mallocFailed ){ - for(j=0, pAndTerm=pAndWC->a; j<pAndWC->nTerm; j++, pAndTerm++){ - assert( pAndTerm->pExpr ); - if( allowedOp(pAndTerm->pExpr->op) - || pAndTerm->eOperator==WO_AUX - ){ - b |= sqlite3WhereGetMask(&pWInfo->sMaskSet, pAndTerm->leftCursor); - } - } - } - indexable &= b; - } - }else if( pOrTerm->wtFlags & TERM_COPIED ){ - /* Skip this term for now. We revisit it when we process the - ** corresponding TERM_VIRTUAL term */ - }else{ - Bitmask b; - b = sqlite3WhereGetMask(&pWInfo->sMaskSet, pOrTerm->leftCursor); - if( pOrTerm->wtFlags & TERM_VIRTUAL ){ - WhereTerm *pOther = &pOrWc->a[pOrTerm->iParent]; - b |= sqlite3WhereGetMask(&pWInfo->sMaskSet, pOther->leftCursor); - } - indexable &= b; - if( (pOrTerm->eOperator & WO_EQ)==0 ){ - chngToIN = 0; - }else{ - chngToIN &= b; - } - } - } - - /* - ** Record the set of tables that satisfy case 3. The set might be - ** empty. - */ - pOrInfo->indexable = indexable; - pTerm->eOperator = indexable==0 ? 0 : WO_OR; - - /* For a two-way OR, attempt to implementation case 2. - */ - if( indexable && pOrWc->nTerm==2 ){ - int iOne = 0; - WhereTerm *pOne; - while( (pOne = whereNthSubterm(&pOrWc->a[0],iOne++))!=0 ){ - int iTwo = 0; - WhereTerm *pTwo; - while( (pTwo = whereNthSubterm(&pOrWc->a[1],iTwo++))!=0 ){ - whereCombineDisjuncts(pSrc, pWC, pOne, pTwo); - } - } - } - - /* - ** chngToIN holds a set of tables that *might* satisfy case 1. But - ** we have to do some additional checking to see if case 1 really - ** is satisfied. - ** - ** chngToIN will hold either 0, 1, or 2 bits. The 0-bit case means - ** that there is no possibility of transforming the OR clause into an - ** IN operator because one or more terms in the OR clause contain - ** something other than == on a column in the single table. The 1-bit - ** case means that every term of the OR clause is of the form - ** "table.column=expr" for some single table. The one bit that is set - ** will correspond to the common table. We still need to check to make - ** sure the same column is used on all terms. The 2-bit case is when - ** the all terms are of the form "table1.column=table2.column". It - ** might be possible to form an IN operator with either table1.column - ** or table2.column as the LHS if either is common to every term of - ** the OR clause. - ** - ** Note that terms of the form "table.column1=table.column2" (the - ** same table on both sizes of the ==) cannot be optimized. - */ - if( chngToIN ){ - int okToChngToIN = 0; /* True if the conversion to IN is valid */ - int iColumn = -1; /* Column index on lhs of IN operator */ - int iCursor = -1; /* Table cursor common to all terms */ - int j = 0; /* Loop counter */ - - /* Search for a table and column that appears on one side or the - ** other of the == operator in every subterm. That table and column - ** will be recorded in iCursor and iColumn. There might not be any - ** such table and column. Set okToChngToIN if an appropriate table - ** and column is found but leave okToChngToIN false if not found. - */ - for(j=0; j<2 && !okToChngToIN; j++){ - pOrTerm = pOrWc->a; - for(i=pOrWc->nTerm-1; i>=0; i--, pOrTerm++){ - assert( pOrTerm->eOperator & WO_EQ ); - pOrTerm->wtFlags &= ~TERM_OR_OK; - if( pOrTerm->leftCursor==iCursor ){ - /* This is the 2-bit case and we are on the second iteration and - ** current term is from the first iteration. So skip this term. */ - assert( j==1 ); - continue; - } - if( (chngToIN & sqlite3WhereGetMask(&pWInfo->sMaskSet, - pOrTerm->leftCursor))==0 ){ - /* This term must be of the form t1.a==t2.b where t2 is in the - ** chngToIN set but t1 is not. This term will be either preceded - ** or follwed by an inverted copy (t2.b==t1.a). Skip this term - ** and use its inversion. */ - testcase( pOrTerm->wtFlags & TERM_COPIED ); - testcase( pOrTerm->wtFlags & TERM_VIRTUAL ); - assert( pOrTerm->wtFlags & (TERM_COPIED|TERM_VIRTUAL) ); - continue; - } - iColumn = pOrTerm->u.leftColumn; - iCursor = pOrTerm->leftCursor; - break; - } - if( i<0 ){ - /* No candidate table+column was found. This can only occur - ** on the second iteration */ - assert( j==1 ); - assert( IsPowerOfTwo(chngToIN) ); - assert( chngToIN==sqlite3WhereGetMask(&pWInfo->sMaskSet, iCursor) ); - break; - } - testcase( j==1 ); - - /* We have found a candidate table and column. Check to see if that - ** table and column is common to every term in the OR clause */ - okToChngToIN = 1; - for(; i>=0 && okToChngToIN; i--, pOrTerm++){ - assert( pOrTerm->eOperator & WO_EQ ); - if( pOrTerm->leftCursor!=iCursor ){ - pOrTerm->wtFlags &= ~TERM_OR_OK; - }else if( pOrTerm->u.leftColumn!=iColumn ){ - okToChngToIN = 0; - }else{ - int affLeft, affRight; - /* If the right-hand side is also a column, then the affinities - ** of both right and left sides must be such that no type - ** conversions are required on the right. (Ticket #2249) - */ - affRight = sqlite3ExprAffinity(pOrTerm->pExpr->pRight); - affLeft = sqlite3ExprAffinity(pOrTerm->pExpr->pLeft); - if( affRight!=0 && affRight!=affLeft ){ - okToChngToIN = 0; - }else{ - pOrTerm->wtFlags |= TERM_OR_OK; - } - } - } - } - - /* At this point, okToChngToIN is true if original pTerm satisfies - ** case 1. In that case, construct a new virtual term that is - ** pTerm converted into an IN operator. - */ - if( okToChngToIN ){ - Expr *pDup; /* A transient duplicate expression */ - ExprList *pList = 0; /* The RHS of the IN operator */ - Expr *pLeft = 0; /* The LHS of the IN operator */ - Expr *pNew; /* The complete IN operator */ - - for(i=pOrWc->nTerm-1, pOrTerm=pOrWc->a; i>=0; i--, pOrTerm++){ - if( (pOrTerm->wtFlags & TERM_OR_OK)==0 ) continue; - assert( pOrTerm->eOperator & WO_EQ ); - assert( pOrTerm->leftCursor==iCursor ); - assert( pOrTerm->u.leftColumn==iColumn ); - pDup = sqlite3ExprDup(db, pOrTerm->pExpr->pRight, 0); - pList = sqlite3ExprListAppend(pWInfo->pParse, pList, pDup); - pLeft = pOrTerm->pExpr->pLeft; - } - assert( pLeft!=0 ); - pDup = sqlite3ExprDup(db, pLeft, 0); - pNew = sqlite3PExpr(pParse, TK_IN, pDup, 0); - if( pNew ){ - int idxNew; - transferJoinMarkings(pNew, pExpr); - assert( !ExprHasProperty(pNew, EP_xIsSelect) ); - pNew->x.pList = pList; - idxNew = whereClauseInsert(pWC, pNew, TERM_VIRTUAL|TERM_DYNAMIC); - testcase( idxNew==0 ); - exprAnalyze(pSrc, pWC, idxNew); - pTerm = &pWC->a[idxTerm]; - markTermAsChild(pWC, idxNew, idxTerm); - }else{ - sqlite3ExprListDelete(db, pList); - } - } - } -} -#endif /* !SQLITE_OMIT_OR_OPTIMIZATION && !SQLITE_OMIT_SUBQUERY */ - -/* -** We already know that pExpr is a binary operator where both operands are -** column references. This routine checks to see if pExpr is an equivalence -** relation: -** 1. The SQLITE_Transitive optimization must be enabled -** 2. Must be either an == or an IS operator -** 3. Not originating in the ON clause of an OUTER JOIN -** 4. The affinities of A and B must be compatible -** 5a. Both operands use the same collating sequence OR -** 5b. The overall collating sequence is BINARY -** If this routine returns TRUE, that means that the RHS can be substituted -** for the LHS anyplace else in the WHERE clause where the LHS column occurs. -** This is an optimization. No harm comes from returning 0. But if 1 is -** returned when it should not be, then incorrect answers might result. -*/ -static int termIsEquivalence(Parse *pParse, Expr *pExpr){ - char aff1, aff2; - CollSeq *pColl; - if( !OptimizationEnabled(pParse->db, SQLITE_Transitive) ) return 0; - if( pExpr->op!=TK_EQ && pExpr->op!=TK_IS ) return 0; - if( ExprHasProperty(pExpr, EP_FromJoin) ) return 0; - aff1 = sqlite3ExprAffinity(pExpr->pLeft); - aff2 = sqlite3ExprAffinity(pExpr->pRight); - if( aff1!=aff2 - && (!sqlite3IsNumericAffinity(aff1) || !sqlite3IsNumericAffinity(aff2)) - ){ - return 0; - } - pColl = sqlite3BinaryCompareCollSeq(pParse, pExpr->pLeft, pExpr->pRight); - if( pColl==0 || sqlite3StrICmp(pColl->zName, "BINARY")==0 ) return 1; - return sqlite3ExprCollSeqMatch(pParse, pExpr->pLeft, pExpr->pRight); -} - -/* -** Recursively walk the expressions of a SELECT statement and generate -** a bitmask indicating which tables are used in that expression -** tree. -*/ -static Bitmask exprSelectUsage(WhereMaskSet *pMaskSet, Select *pS){ - Bitmask mask = 0; - while( pS ){ - SrcList *pSrc = pS->pSrc; - mask |= sqlite3WhereExprListUsage(pMaskSet, pS->pEList); - mask |= sqlite3WhereExprListUsage(pMaskSet, pS->pGroupBy); - mask |= sqlite3WhereExprListUsage(pMaskSet, pS->pOrderBy); - mask |= sqlite3WhereExprUsage(pMaskSet, pS->pWhere); - mask |= sqlite3WhereExprUsage(pMaskSet, pS->pHaving); - if( ALWAYS(pSrc!=0) ){ - int i; - for(i=0; i<pSrc->nSrc; i++){ - mask |= exprSelectUsage(pMaskSet, pSrc->a[i].pSelect); - mask |= sqlite3WhereExprUsage(pMaskSet, pSrc->a[i].pOn); - if( pSrc->a[i].fg.isTabFunc ){ - mask |= sqlite3WhereExprListUsage(pMaskSet, pSrc->a[i].u1.pFuncArg); - } - } - } - pS = pS->pPrior; - } - return mask; -} - -/* -** Expression pExpr is one operand of a comparison operator that might -** be useful for indexing. This routine checks to see if pExpr appears -** in any index. Return TRUE (1) if pExpr is an indexed term and return -** FALSE (0) if not. If TRUE is returned, also set aiCurCol[0] to the cursor -** number of the table that is indexed and aiCurCol[1] to the column number -** of the column that is indexed, or XN_EXPR (-2) if an expression is being -** indexed. -** -** If pExpr is a TK_COLUMN column reference, then this routine always returns -** true even if that particular column is not indexed, because the column -** might be added to an automatic index later. -*/ -static SQLITE_NOINLINE int exprMightBeIndexed2( - SrcList *pFrom, /* The FROM clause */ - Bitmask mPrereq, /* Bitmask of FROM clause terms referenced by pExpr */ - int *aiCurCol, /* Write the referenced table cursor and column here */ - Expr *pExpr /* An operand of a comparison operator */ -){ - Index *pIdx; - int i; - int iCur; - for(i=0; mPrereq>1; i++, mPrereq>>=1){} - iCur = pFrom->a[i].iCursor; - for(pIdx=pFrom->a[i].pTab->pIndex; pIdx; pIdx=pIdx->pNext){ - if( pIdx->aColExpr==0 ) continue; - for(i=0; i<pIdx->nKeyCol; i++){ - if( pIdx->aiColumn[i]!=XN_EXPR ) continue; - if( sqlite3ExprCompareSkip(pExpr, pIdx->aColExpr->a[i].pExpr, iCur)==0 ){ - aiCurCol[0] = iCur; - aiCurCol[1] = XN_EXPR; - return 1; - } - } - } - return 0; -} -static int exprMightBeIndexed( - SrcList *pFrom, /* The FROM clause */ - Bitmask mPrereq, /* Bitmask of FROM clause terms referenced by pExpr */ - int *aiCurCol, /* Write the referenced table cursor & column here */ - Expr *pExpr, /* An operand of a comparison operator */ - int op /* The specific comparison operator */ -){ - /* If this expression is a vector to the left or right of a - ** inequality constraint (>, <, >= or <=), perform the processing - ** on the first element of the vector. */ - assert( TK_GT+1==TK_LE && TK_GT+2==TK_LT && TK_GT+3==TK_GE ); - assert( TK_IS<TK_GE && TK_ISNULL<TK_GE && TK_IN<TK_GE ); - assert( op<=TK_GE ); - if( pExpr->op==TK_VECTOR && (op>=TK_GT && ALWAYS(op<=TK_GE)) ){ - pExpr = pExpr->x.pList->a[0].pExpr; - } - - if( pExpr->op==TK_COLUMN ){ - aiCurCol[0] = pExpr->iTable; - aiCurCol[1] = pExpr->iColumn; - return 1; - } - if( mPrereq==0 ) return 0; /* No table references */ - if( (mPrereq&(mPrereq-1))!=0 ) return 0; /* Refs more than one table */ - return exprMightBeIndexed2(pFrom,mPrereq,aiCurCol,pExpr); -} - -/* -** The input to this routine is an WhereTerm structure with only the -** "pExpr" field filled in. The job of this routine is to analyze the -** subexpression and populate all the other fields of the WhereTerm -** structure. -** -** If the expression is of the form "<expr> <op> X" it gets commuted -** to the standard form of "X <op> <expr>". -** -** If the expression is of the form "X <op> Y" where both X and Y are -** columns, then the original expression is unchanged and a new virtual -** term of the form "Y <op> X" is added to the WHERE clause and -** analyzed separately. The original term is marked with TERM_COPIED -** and the new term is marked with TERM_DYNAMIC (because it's pExpr -** needs to be freed with the WhereClause) and TERM_VIRTUAL (because it -** is a commuted copy of a prior term.) The original term has nChild=1 -** and the copy has idxParent set to the index of the original term. -*/ -static void exprAnalyze( - SrcList *pSrc, /* the FROM clause */ - WhereClause *pWC, /* the WHERE clause */ - int idxTerm /* Index of the term to be analyzed */ -){ - WhereInfo *pWInfo = pWC->pWInfo; /* WHERE clause processing context */ - WhereTerm *pTerm; /* The term to be analyzed */ - WhereMaskSet *pMaskSet; /* Set of table index masks */ - Expr *pExpr; /* The expression to be analyzed */ - Bitmask prereqLeft; /* Prerequesites of the pExpr->pLeft */ - Bitmask prereqAll; /* Prerequesites of pExpr */ - Bitmask extraRight = 0; /* Extra dependencies on LEFT JOIN */ - Expr *pStr1 = 0; /* RHS of LIKE/GLOB operator */ - int isComplete = 0; /* RHS of LIKE/GLOB ends with wildcard */ - int noCase = 0; /* uppercase equivalent to lowercase */ - int op; /* Top-level operator. pExpr->op */ - Parse *pParse = pWInfo->pParse; /* Parsing context */ - sqlite3 *db = pParse->db; /* Database connection */ - unsigned char eOp2 = 0; /* op2 value for LIKE/REGEXP/GLOB */ - int nLeft; /* Number of elements on left side vector */ - - if( db->mallocFailed ){ - return; - } - pTerm = &pWC->a[idxTerm]; - pMaskSet = &pWInfo->sMaskSet; - pExpr = pTerm->pExpr; - assert( pExpr->op!=TK_AS && pExpr->op!=TK_COLLATE ); - prereqLeft = sqlite3WhereExprUsage(pMaskSet, pExpr->pLeft); - op = pExpr->op; - if( op==TK_IN ){ - assert( pExpr->pRight==0 ); - if( sqlite3ExprCheckIN(pParse, pExpr) ) return; - if( ExprHasProperty(pExpr, EP_xIsSelect) ){ - pTerm->prereqRight = exprSelectUsage(pMaskSet, pExpr->x.pSelect); - }else{ - pTerm->prereqRight = sqlite3WhereExprListUsage(pMaskSet, pExpr->x.pList); - } - }else if( op==TK_ISNULL ){ - pTerm->prereqRight = 0; - }else{ - pTerm->prereqRight = sqlite3WhereExprUsage(pMaskSet, pExpr->pRight); - } - pMaskSet->bVarSelect = 0; - prereqAll = sqlite3WhereExprUsage(pMaskSet, pExpr); - if( pMaskSet->bVarSelect ) pTerm->wtFlags |= TERM_VARSELECT; - if( ExprHasProperty(pExpr, EP_FromJoin) ){ - Bitmask x = sqlite3WhereGetMask(pMaskSet, pExpr->iRightJoinTable); - prereqAll |= x; - extraRight = x-1; /* ON clause terms may not be used with an index - ** on left table of a LEFT JOIN. Ticket #3015 */ - if( (prereqAll>>1)>=x ){ - sqlite3ErrorMsg(pParse, "ON clause references tables to its right"); - return; - } - } - pTerm->prereqAll = prereqAll; - pTerm->leftCursor = -1; - pTerm->iParent = -1; - pTerm->eOperator = 0; - if( allowedOp(op) ){ - int aiCurCol[2]; - Expr *pLeft = sqlite3ExprSkipCollate(pExpr->pLeft); - Expr *pRight = sqlite3ExprSkipCollate(pExpr->pRight); - u16 opMask = (pTerm->prereqRight & prereqLeft)==0 ? WO_ALL : WO_EQUIV; - - if( pTerm->iField>0 ){ - assert( op==TK_IN ); - assert( pLeft->op==TK_VECTOR ); - pLeft = pLeft->x.pList->a[pTerm->iField-1].pExpr; - } - - if( exprMightBeIndexed(pSrc, prereqLeft, aiCurCol, pLeft, op) ){ - pTerm->leftCursor = aiCurCol[0]; - pTerm->u.leftColumn = aiCurCol[1]; - pTerm->eOperator = operatorMask(op) & opMask; - } - if( op==TK_IS ) pTerm->wtFlags |= TERM_IS; - if( pRight - && exprMightBeIndexed(pSrc, pTerm->prereqRight, aiCurCol, pRight, op) - ){ - WhereTerm *pNew; - Expr *pDup; - u16 eExtraOp = 0; /* Extra bits for pNew->eOperator */ - assert( pTerm->iField==0 ); - if( pTerm->leftCursor>=0 ){ - int idxNew; - pDup = sqlite3ExprDup(db, pExpr, 0); - if( db->mallocFailed ){ - sqlite3ExprDelete(db, pDup); - return; - } - idxNew = whereClauseInsert(pWC, pDup, TERM_VIRTUAL|TERM_DYNAMIC); - if( idxNew==0 ) return; - pNew = &pWC->a[idxNew]; - markTermAsChild(pWC, idxNew, idxTerm); - if( op==TK_IS ) pNew->wtFlags |= TERM_IS; - pTerm = &pWC->a[idxTerm]; - pTerm->wtFlags |= TERM_COPIED; - - if( termIsEquivalence(pParse, pDup) ){ - pTerm->eOperator |= WO_EQUIV; - eExtraOp = WO_EQUIV; - } - }else{ - pDup = pExpr; - pNew = pTerm; - } - exprCommute(pParse, pDup); - pNew->leftCursor = aiCurCol[0]; - pNew->u.leftColumn = aiCurCol[1]; - testcase( (prereqLeft | extraRight) != prereqLeft ); - pNew->prereqRight = prereqLeft | extraRight; - pNew->prereqAll = prereqAll; - pNew->eOperator = (operatorMask(pDup->op) + eExtraOp) & opMask; - } - } - -#ifndef SQLITE_OMIT_BETWEEN_OPTIMIZATION - /* If a term is the BETWEEN operator, create two new virtual terms - ** that define the range that the BETWEEN implements. For example: - ** - ** a BETWEEN b AND c - ** - ** is converted into: - ** - ** (a BETWEEN b AND c) AND (a>=b) AND (a<=c) - ** - ** The two new terms are added onto the end of the WhereClause object. - ** The new terms are "dynamic" and are children of the original BETWEEN - ** term. That means that if the BETWEEN term is coded, the children are - ** skipped. Or, if the children are satisfied by an index, the original - ** BETWEEN term is skipped. - */ - else if( pExpr->op==TK_BETWEEN && pWC->op==TK_AND ){ - ExprList *pList = pExpr->x.pList; - int i; - static const u8 ops[] = {TK_GE, TK_LE}; - assert( pList!=0 ); - assert( pList->nExpr==2 ); - for(i=0; i<2; i++){ - Expr *pNewExpr; - int idxNew; - pNewExpr = sqlite3PExpr(pParse, ops[i], - sqlite3ExprDup(db, pExpr->pLeft, 0), - sqlite3ExprDup(db, pList->a[i].pExpr, 0)); - transferJoinMarkings(pNewExpr, pExpr); - idxNew = whereClauseInsert(pWC, pNewExpr, TERM_VIRTUAL|TERM_DYNAMIC); - testcase( idxNew==0 ); - exprAnalyze(pSrc, pWC, idxNew); - pTerm = &pWC->a[idxTerm]; - markTermAsChild(pWC, idxNew, idxTerm); - } - } -#endif /* SQLITE_OMIT_BETWEEN_OPTIMIZATION */ - -#if !defined(SQLITE_OMIT_OR_OPTIMIZATION) && !defined(SQLITE_OMIT_SUBQUERY) - /* Analyze a term that is composed of two or more subterms connected by - ** an OR operator. - */ - else if( pExpr->op==TK_OR ){ - assert( pWC->op==TK_AND ); - exprAnalyzeOrTerm(pSrc, pWC, idxTerm); - pTerm = &pWC->a[idxTerm]; - } -#endif /* SQLITE_OMIT_OR_OPTIMIZATION */ - -#ifndef SQLITE_OMIT_LIKE_OPTIMIZATION - /* Add constraints to reduce the search space on a LIKE or GLOB - ** operator. - ** - ** A like pattern of the form "x LIKE 'aBc%'" is changed into constraints - ** - ** x>='ABC' AND x<'abd' AND x LIKE 'aBc%' - ** - ** The last character of the prefix "abc" is incremented to form the - ** termination condition "abd". If case is not significant (the default - ** for LIKE) then the lower-bound is made all uppercase and the upper- - ** bound is made all lowercase so that the bounds also work when comparing - ** BLOBs. - */ - if( pWC->op==TK_AND - && isLikeOrGlob(pParse, pExpr, &pStr1, &isComplete, &noCase) - ){ - Expr *pLeft; /* LHS of LIKE/GLOB operator */ - Expr *pStr2; /* Copy of pStr1 - RHS of LIKE/GLOB operator */ - Expr *pNewExpr1; - Expr *pNewExpr2; - int idxNew1; - int idxNew2; - const char *zCollSeqName; /* Name of collating sequence */ - const u16 wtFlags = TERM_LIKEOPT | TERM_VIRTUAL | TERM_DYNAMIC; - - pLeft = pExpr->x.pList->a[1].pExpr; - pStr2 = sqlite3ExprDup(db, pStr1, 0); - - /* Convert the lower bound to upper-case and the upper bound to - ** lower-case (upper-case is less than lower-case in ASCII) so that - ** the range constraints also work for BLOBs - */ - if( noCase && !pParse->db->mallocFailed ){ - int i; - char c; - pTerm->wtFlags |= TERM_LIKE; - for(i=0; (c = pStr1->u.zToken[i])!=0; i++){ - pStr1->u.zToken[i] = sqlite3Toupper(c); - pStr2->u.zToken[i] = sqlite3Tolower(c); - } - } - - if( !db->mallocFailed ){ - u8 c, *pC; /* Last character before the first wildcard */ - pC = (u8*)&pStr2->u.zToken[sqlite3Strlen30(pStr2->u.zToken)-1]; - c = *pC; - if( noCase ){ - /* The point is to increment the last character before the first - ** wildcard. But if we increment '@', that will push it into the - ** alphabetic range where case conversions will mess up the - ** inequality. To avoid this, make sure to also run the full - ** LIKE on all candidate expressions by clearing the isComplete flag - */ - if( c=='A'-1 ) isComplete = 0; - c = sqlite3UpperToLower[c]; - } - *pC = c + 1; - } - zCollSeqName = noCase ? "NOCASE" : "BINARY"; - pNewExpr1 = sqlite3ExprDup(db, pLeft, 0); - pNewExpr1 = sqlite3PExpr(pParse, TK_GE, - sqlite3ExprAddCollateString(pParse,pNewExpr1,zCollSeqName), - pStr1); - transferJoinMarkings(pNewExpr1, pExpr); - idxNew1 = whereClauseInsert(pWC, pNewExpr1, wtFlags); - testcase( idxNew1==0 ); - exprAnalyze(pSrc, pWC, idxNew1); - pNewExpr2 = sqlite3ExprDup(db, pLeft, 0); - pNewExpr2 = sqlite3PExpr(pParse, TK_LT, - sqlite3ExprAddCollateString(pParse,pNewExpr2,zCollSeqName), - pStr2); - transferJoinMarkings(pNewExpr2, pExpr); - idxNew2 = whereClauseInsert(pWC, pNewExpr2, wtFlags); - testcase( idxNew2==0 ); - exprAnalyze(pSrc, pWC, idxNew2); - pTerm = &pWC->a[idxTerm]; - if( isComplete ){ - markTermAsChild(pWC, idxNew1, idxTerm); - markTermAsChild(pWC, idxNew2, idxTerm); - } - } -#endif /* SQLITE_OMIT_LIKE_OPTIMIZATION */ - -#ifndef SQLITE_OMIT_VIRTUALTABLE - /* Add a WO_AUX auxiliary term to the constraint set if the - ** current expression is of the form "column OP expr" where OP - ** is an operator that gets passed into virtual tables but which is - ** not normally optimized for ordinary tables. In other words, OP - ** is one of MATCH, LIKE, GLOB, REGEXP, !=, IS, IS NOT, or NOT NULL. - ** This information is used by the xBestIndex methods of - ** virtual tables. The native query optimizer does not attempt - ** to do anything with MATCH functions. - */ - if( pWC->op==TK_AND ){ - Expr *pRight = 0, *pLeft = 0; - int res = isAuxiliaryVtabOperator(pExpr, &eOp2, &pLeft, &pRight); - while( res-- > 0 ){ - int idxNew; - WhereTerm *pNewTerm; - Bitmask prereqColumn, prereqExpr; - - prereqExpr = sqlite3WhereExprUsage(pMaskSet, pRight); - prereqColumn = sqlite3WhereExprUsage(pMaskSet, pLeft); - if( (prereqExpr & prereqColumn)==0 ){ - Expr *pNewExpr; - pNewExpr = sqlite3PExpr(pParse, TK_MATCH, - 0, sqlite3ExprDup(db, pRight, 0)); - if( ExprHasProperty(pExpr, EP_FromJoin) && pNewExpr ){ - ExprSetProperty(pNewExpr, EP_FromJoin); - } - idxNew = whereClauseInsert(pWC, pNewExpr, TERM_VIRTUAL|TERM_DYNAMIC); - testcase( idxNew==0 ); - pNewTerm = &pWC->a[idxNew]; - pNewTerm->prereqRight = prereqExpr; - pNewTerm->leftCursor = pLeft->iTable; - pNewTerm->u.leftColumn = pLeft->iColumn; - pNewTerm->eOperator = WO_AUX; - pNewTerm->eMatchOp = eOp2; - markTermAsChild(pWC, idxNew, idxTerm); - pTerm = &pWC->a[idxTerm]; - pTerm->wtFlags |= TERM_COPIED; - pNewTerm->prereqAll = pTerm->prereqAll; - } - SWAP(Expr*, pLeft, pRight); - } - } -#endif /* SQLITE_OMIT_VIRTUALTABLE */ - - /* If there is a vector == or IS term - e.g. "(a, b) == (?, ?)" - create - ** new terms for each component comparison - "a = ?" and "b = ?". The - ** new terms completely replace the original vector comparison, which is - ** no longer used. - ** - ** This is only required if at least one side of the comparison operation - ** is not a sub-select. */ - if( pWC->op==TK_AND - && (pExpr->op==TK_EQ || pExpr->op==TK_IS) - && (nLeft = sqlite3ExprVectorSize(pExpr->pLeft))>1 - && sqlite3ExprVectorSize(pExpr->pRight)==nLeft - && ( (pExpr->pLeft->flags & EP_xIsSelect)==0 - || (pExpr->pRight->flags & EP_xIsSelect)==0) - ){ - int i; - for(i=0; i<nLeft; i++){ - int idxNew; - Expr *pNew; - Expr *pLeft = sqlite3ExprForVectorField(pParse, pExpr->pLeft, i); - Expr *pRight = sqlite3ExprForVectorField(pParse, pExpr->pRight, i); - - pNew = sqlite3PExpr(pParse, pExpr->op, pLeft, pRight); - transferJoinMarkings(pNew, pExpr); - idxNew = whereClauseInsert(pWC, pNew, TERM_DYNAMIC); - exprAnalyze(pSrc, pWC, idxNew); - } - pTerm = &pWC->a[idxTerm]; - pTerm->wtFlags |= TERM_CODED|TERM_VIRTUAL; /* Disable the original */ - pTerm->eOperator = 0; - } - - /* If there is a vector IN term - e.g. "(a, b) IN (SELECT ...)" - create - ** a virtual term for each vector component. The expression object - ** used by each such virtual term is pExpr (the full vector IN(...) - ** expression). The WhereTerm.iField variable identifies the index within - ** the vector on the LHS that the virtual term represents. - ** - ** This only works if the RHS is a simple SELECT, not a compound - */ - if( pWC->op==TK_AND && pExpr->op==TK_IN && pTerm->iField==0 - && pExpr->pLeft->op==TK_VECTOR - && pExpr->x.pSelect->pPrior==0 - ){ - int i; - for(i=0; i<sqlite3ExprVectorSize(pExpr->pLeft); i++){ - int idxNew; - idxNew = whereClauseInsert(pWC, pExpr, TERM_VIRTUAL); - pWC->a[idxNew].iField = i+1; - exprAnalyze(pSrc, pWC, idxNew); - markTermAsChild(pWC, idxNew, idxTerm); - } - } - -#ifdef SQLITE_ENABLE_STAT3_OR_STAT4 - /* When sqlite_stat3 histogram data is available an operator of the - ** form "x IS NOT NULL" can sometimes be evaluated more efficiently - ** as "x>NULL" if x is not an INTEGER PRIMARY KEY. So construct a - ** virtual term of that form. - ** - ** Note that the virtual term must be tagged with TERM_VNULL. - */ - if( pExpr->op==TK_NOTNULL - && pExpr->pLeft->op==TK_COLUMN - && pExpr->pLeft->iColumn>=0 - && OptimizationEnabled(db, SQLITE_Stat34) - ){ - Expr *pNewExpr; - Expr *pLeft = pExpr->pLeft; - int idxNew; - WhereTerm *pNewTerm; - - pNewExpr = sqlite3PExpr(pParse, TK_GT, - sqlite3ExprDup(db, pLeft, 0), - sqlite3ExprAlloc(db, TK_NULL, 0, 0)); - - idxNew = whereClauseInsert(pWC, pNewExpr, - TERM_VIRTUAL|TERM_DYNAMIC|TERM_VNULL); - if( idxNew ){ - pNewTerm = &pWC->a[idxNew]; - pNewTerm->prereqRight = 0; - pNewTerm->leftCursor = pLeft->iTable; - pNewTerm->u.leftColumn = pLeft->iColumn; - pNewTerm->eOperator = WO_GT; - markTermAsChild(pWC, idxNew, idxTerm); - pTerm = &pWC->a[idxTerm]; - pTerm->wtFlags |= TERM_COPIED; - pNewTerm->prereqAll = pTerm->prereqAll; - } - } -#endif /* SQLITE_ENABLE_STAT3_OR_STAT4 */ - - /* Prevent ON clause terms of a LEFT JOIN from being used to drive - ** an index for tables to the left of the join. - */ - testcase( pTerm!=&pWC->a[idxTerm] ); - pTerm = &pWC->a[idxTerm]; - pTerm->prereqRight |= extraRight; -} - -/*************************************************************************** -** Routines with file scope above. Interface to the rest of the where.c -** subsystem follows. -***************************************************************************/ - -/* -** This routine identifies subexpressions in the WHERE clause where -** each subexpression is separated by the AND operator or some other -** operator specified in the op parameter. The WhereClause structure -** is filled with pointers to subexpressions. For example: -** -** WHERE a=='hello' AND coalesce(b,11)<10 AND (c+12!=d OR c==22) -** \________/ \_______________/ \________________/ -** slot[0] slot[1] slot[2] -** -** The original WHERE clause in pExpr is unaltered. All this routine -** does is make slot[] entries point to substructure within pExpr. -** -** In the previous sentence and in the diagram, "slot[]" refers to -** the WhereClause.a[] array. The slot[] array grows as needed to contain -** all terms of the WHERE clause. -*/ -void sqlite3WhereSplit(WhereClause *pWC, Expr *pExpr, u8 op){ - Expr *pE2 = sqlite3ExprSkipCollate(pExpr); - pWC->op = op; - if( pE2==0 ) return; - if( pE2->op!=op ){ - whereClauseInsert(pWC, pExpr, 0); - }else{ - sqlite3WhereSplit(pWC, pE2->pLeft, op); - sqlite3WhereSplit(pWC, pE2->pRight, op); - } -} - -/* -** Initialize a preallocated WhereClause structure. -*/ -void sqlite3WhereClauseInit( - WhereClause *pWC, /* The WhereClause to be initialized */ - WhereInfo *pWInfo /* The WHERE processing context */ -){ - pWC->pWInfo = pWInfo; - pWC->pOuter = 0; - pWC->nTerm = 0; - pWC->nSlot = ArraySize(pWC->aStatic); - pWC->a = pWC->aStatic; -} - -/* -** Deallocate a WhereClause structure. The WhereClause structure -** itself is not freed. This routine is the inverse of -** sqlite3WhereClauseInit(). -*/ -void sqlite3WhereClauseClear(WhereClause *pWC){ - int i; - WhereTerm *a; - sqlite3 *db = pWC->pWInfo->pParse->db; - for(i=pWC->nTerm-1, a=pWC->a; i>=0; i--, a++){ - if( a->wtFlags & TERM_DYNAMIC ){ - sqlite3ExprDelete(db, a->pExpr); - } - if( a->wtFlags & TERM_ORINFO ){ - whereOrInfoDelete(db, a->u.pOrInfo); - }else if( a->wtFlags & TERM_ANDINFO ){ - whereAndInfoDelete(db, a->u.pAndInfo); - } - } - if( pWC->a!=pWC->aStatic ){ - sqlite3DbFree(db, pWC->a); - } -} - - -/* -** These routines walk (recursively) an expression tree and generate -** a bitmask indicating which tables are used in that expression -** tree. -*/ -Bitmask sqlite3WhereExprUsage(WhereMaskSet *pMaskSet, Expr *p){ - Bitmask mask; - if( p==0 ) return 0; - if( p->op==TK_COLUMN ){ - return sqlite3WhereGetMask(pMaskSet, p->iTable); - } - mask = (p->op==TK_IF_NULL_ROW) ? sqlite3WhereGetMask(pMaskSet, p->iTable) : 0; - assert( !ExprHasProperty(p, EP_TokenOnly) ); - if( p->pLeft ) mask |= sqlite3WhereExprUsage(pMaskSet, p->pLeft); - if( p->pRight ){ - mask |= sqlite3WhereExprUsage(pMaskSet, p->pRight); - assert( p->x.pList==0 ); - }else if( ExprHasProperty(p, EP_xIsSelect) ){ - if( ExprHasProperty(p, EP_VarSelect) ) pMaskSet->bVarSelect = 1; - mask |= exprSelectUsage(pMaskSet, p->x.pSelect); - }else if( p->x.pList ){ - mask |= sqlite3WhereExprListUsage(pMaskSet, p->x.pList); - } - return mask; -} -Bitmask sqlite3WhereExprListUsage(WhereMaskSet *pMaskSet, ExprList *pList){ - int i; - Bitmask mask = 0; - if( pList ){ - for(i=0; i<pList->nExpr; i++){ - mask |= sqlite3WhereExprUsage(pMaskSet, pList->a[i].pExpr); - } - } - return mask; -} - - -/* -** Call exprAnalyze on all terms in a WHERE clause. -** -** Note that exprAnalyze() might add new virtual terms onto the -** end of the WHERE clause. We do not want to analyze these new -** virtual terms, so start analyzing at the end and work forward -** so that the added virtual terms are never processed. -*/ -void sqlite3WhereExprAnalyze( - SrcList *pTabList, /* the FROM clause */ - WhereClause *pWC /* the WHERE clause to be analyzed */ -){ - int i; - for(i=pWC->nTerm-1; i>=0; i--){ - exprAnalyze(pTabList, pWC, i); - } -} - -/* -** For table-valued-functions, transform the function arguments into -** new WHERE clause terms. -** -** Each function argument translates into an equality constraint against -** a HIDDEN column in the table. -*/ -void sqlite3WhereTabFuncArgs( - Parse *pParse, /* Parsing context */ - struct SrcList_item *pItem, /* The FROM clause term to process */ - WhereClause *pWC /* Xfer function arguments to here */ -){ - Table *pTab; - int j, k; - ExprList *pArgs; - Expr *pColRef; - Expr *pTerm; - if( pItem->fg.isTabFunc==0 ) return; - pTab = pItem->pTab; - assert( pTab!=0 ); - pArgs = pItem->u1.pFuncArg; - if( pArgs==0 ) return; - for(j=k=0; j<pArgs->nExpr; j++){ - while( k<pTab->nCol && (pTab->aCol[k].colFlags & COLFLAG_HIDDEN)==0 ){k++;} - if( k>=pTab->nCol ){ - sqlite3ErrorMsg(pParse, "too many arguments on %s() - max %d", - pTab->zName, j); - return; - } - pColRef = sqlite3ExprAlloc(pParse->db, TK_COLUMN, 0, 0); - if( pColRef==0 ) return; - pColRef->iTable = pItem->iCursor; - pColRef->iColumn = k++; - pColRef->pTab = pTab; - pTerm = sqlite3PExpr(pParse, TK_EQ, pColRef, - sqlite3ExprDup(pParse->db, pArgs->a[j].pExpr, 0)); - whereClauseInsert(pWC, pTerm, TERM_DYNAMIC); - } -} |