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Overview
Comment: | Improved substitution logic in the query flattener. Saves code space, and (more importantly) works correctly with table-valued functions. |
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Downloads: | Tarball | ZIP archive |
Timelines: | family | ancestors | descendants | both | trunk |
Files: | files | file ages | folders |
SHA1: |
3d0bd95e977db50c314d33ec292f99e0 |
User & Date: | drh 2015-10-11 19:46:59.677 |
Context
2015-10-11
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20:08 | Remove an unreachable branch in the query flattener substitution logic. (check-in: 46ee3453a3 user: drh tags: trunk) | |
19:46 | Improved substitution logic in the query flattener. Saves code space, and (more importantly) works correctly with table-valued functions. (check-in: 3d0bd95e97 user: drh tags: trunk) | |
2015-10-10
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16:41 | Work around a "security feature" bug in memcpy() on OpenBSD. (check-in: fab6f09044 user: drh tags: trunk) | |
Changes
Changes to src/select.c.
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3078 3079 3080 3081 3082 3083 3084 | return pParse->nErr!=0; } #endif #if !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW) /* Forward Declarations */ static void substExprList(sqlite3*, ExprList*, int, ExprList*); | | | 3078 3079 3080 3081 3082 3083 3084 3085 3086 3087 3088 3089 3090 3091 3092 | return pParse->nErr!=0; } #endif #if !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW) /* Forward Declarations */ static void substExprList(sqlite3*, ExprList*, int, ExprList*); static void substSelect(sqlite3*, Select *, int, ExprList*, int); /* ** Scan through the expression pExpr. Replace every reference to ** a column in table number iTable with a copy of the iColumn-th ** entry in pEList. (But leave references to the ROWID column ** unchanged.) ** |
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3115 3116 3117 3118 3119 3120 3121 | sqlite3ExprDelete(db, pExpr); pExpr = pNew; } }else{ pExpr->pLeft = substExpr(db, pExpr->pLeft, iTable, pEList); pExpr->pRight = substExpr(db, pExpr->pRight, iTable, pEList); if( ExprHasProperty(pExpr, EP_xIsSelect) ){ | | | 3115 3116 3117 3118 3119 3120 3121 3122 3123 3124 3125 3126 3127 3128 3129 | sqlite3ExprDelete(db, pExpr); pExpr = pNew; } }else{ pExpr->pLeft = substExpr(db, pExpr->pLeft, iTable, pEList); pExpr->pRight = substExpr(db, pExpr->pRight, iTable, pEList); if( ExprHasProperty(pExpr, EP_xIsSelect) ){ substSelect(db, pExpr->x.pSelect, iTable, pEList, 1); }else{ substExprList(db, pExpr->x.pList, iTable, pEList); } } return pExpr; } static void substExprList( |
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3138 3139 3140 3141 3142 3143 3144 | pList->a[i].pExpr = substExpr(db, pList->a[i].pExpr, iTable, pEList); } } static void substSelect( sqlite3 *db, /* Report malloc errors here */ Select *p, /* SELECT statement in which to make substitutions */ int iTable, /* Table to be replaced */ | | > > < < | | > > > > | 3138 3139 3140 3141 3142 3143 3144 3145 3146 3147 3148 3149 3150 3151 3152 3153 3154 3155 3156 3157 3158 3159 3160 3161 3162 3163 3164 3165 3166 3167 3168 3169 3170 3171 3172 3173 3174 3175 | pList->a[i].pExpr = substExpr(db, pList->a[i].pExpr, iTable, pEList); } } static void substSelect( sqlite3 *db, /* Report malloc errors here */ Select *p, /* SELECT statement in which to make substitutions */ int iTable, /* Table to be replaced */ ExprList *pEList, /* Substitute values */ int doPrior /* Do substitutes on p->pPrior too */ ){ SrcList *pSrc; struct SrcList_item *pItem; int i; if( !p ) return; do{ substExprList(db, p->pEList, iTable, pEList); substExprList(db, p->pGroupBy, iTable, pEList); substExprList(db, p->pOrderBy, iTable, pEList); p->pHaving = substExpr(db, p->pHaving, iTable, pEList); p->pWhere = substExpr(db, p->pWhere, iTable, pEList); pSrc = p->pSrc; if( pSrc ){ for(i=pSrc->nSrc, pItem=pSrc->a; i>0; i--, pItem++){ substSelect(db, pItem->pSelect, iTable, pEList, 1); if( pItem->fg.isTabFunc ){ substExprList(db, pItem->u1.pFuncArg, iTable, pEList); } } } }while( doPrior && (p = p->pPrior)!=0 ); } #endif /* !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW) */ #if !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW) /* ** This routine attempts to flatten subqueries as a performance optimization. ** This routine returns 1 if it makes changes and 0 if no flattening occurs. ** |
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3308 3309 3310 3311 3312 3313 3314 | Parse *pParse, /* Parsing context */ Select *p, /* The parent or outer SELECT statement */ int iFrom, /* Index in p->pSrc->a[] of the inner subquery */ int isAgg, /* True if outer SELECT uses aggregate functions */ int subqueryIsAgg /* True if the subquery uses aggregate functions */ ){ const char *zSavedAuthContext = pParse->zAuthContext; | | | 3312 3313 3314 3315 3316 3317 3318 3319 3320 3321 3322 3323 3324 3325 3326 | Parse *pParse, /* Parsing context */ Select *p, /* The parent or outer SELECT statement */ int iFrom, /* Index in p->pSrc->a[] of the inner subquery */ int isAgg, /* True if outer SELECT uses aggregate functions */ int subqueryIsAgg /* True if the subquery uses aggregate functions */ ){ const char *zSavedAuthContext = pParse->zAuthContext; Select *pParent; /* Current UNION ALL term of the other query */ Select *pSub; /* The inner query or "subquery" */ Select *pSub1; /* Pointer to the rightmost select in sub-query */ SrcList *pSrc; /* The FROM clause of the outer query */ SrcList *pSubSrc; /* The FROM clause of the subquery */ ExprList *pList; /* The result set of the outer query */ int iParent; /* VDBE cursor number of the pSub result set temp table */ int i; /* Loop counter */ |
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3603 3604 3605 3606 3607 3608 3609 | ** ** Example: ** ** SELECT * FROM tabA, (SELECT * FROM sub1, sub2), tabB; ** ** The outer query has 3 slots in its FROM clause. One slot of the ** outer query (the middle slot) is used by the subquery. The next | | | | | 3607 3608 3609 3610 3611 3612 3613 3614 3615 3616 3617 3618 3619 3620 3621 3622 3623 | ** ** Example: ** ** SELECT * FROM tabA, (SELECT * FROM sub1, sub2), tabB; ** ** The outer query has 3 slots in its FROM clause. One slot of the ** outer query (the middle slot) is used by the subquery. The next ** block of code will expand the outer query FROM clause to 4 slots. ** The middle slot is expanded to two slots in order to make space ** for the two elements in the FROM clause of the subquery. */ if( nSubSrc>1 ){ pParent->pSrc = pSrc = sqlite3SrcListEnlarge(db, pSrc, nSubSrc-1,iFrom+1); if( db->mallocFailed ){ break; } } |
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3644 3645 3646 3647 3648 3649 3650 | for(i=0; i<pList->nExpr; i++){ if( pList->a[i].zName==0 ){ char *zName = sqlite3DbStrDup(db, pList->a[i].zSpan); sqlite3Dequote(zName); pList->a[i].zName = zName; } } | < < < < < < < < < < < < < > | 3648 3649 3650 3651 3652 3653 3654 3655 3656 3657 3658 3659 3660 3661 3662 3663 3664 3665 3666 3667 3668 3669 3670 3671 3672 3673 3674 3675 3676 3677 3678 3679 3680 3681 3682 3683 3684 3685 3686 3687 3688 3689 3690 3691 3692 3693 3694 | for(i=0; i<pList->nExpr; i++){ if( pList->a[i].zName==0 ){ char *zName = sqlite3DbStrDup(db, pList->a[i].zSpan); sqlite3Dequote(zName); pList->a[i].zName = zName; } } if( pSub->pOrderBy ){ /* At this point, any non-zero iOrderByCol values indicate that the ** ORDER BY column expression is identical to the iOrderByCol'th ** expression returned by SELECT statement pSub. Since these values ** do not necessarily correspond to columns in SELECT statement pParent, ** zero them before transfering the ORDER BY clause. ** ** Not doing this may cause an error if a subsequent call to this ** function attempts to flatten a compound sub-query into pParent ** (the only way this can happen is if the compound sub-query is ** currently part of pSub->pSrc). See ticket [d11a6e908f]. */ ExprList *pOrderBy = pSub->pOrderBy; for(i=0; i<pOrderBy->nExpr; i++){ pOrderBy->a[i].u.x.iOrderByCol = 0; } assert( pParent->pOrderBy==0 ); assert( pSub->pPrior==0 ); pParent->pOrderBy = pOrderBy; pSub->pOrderBy = 0; } pWhere = sqlite3ExprDup(db, pSub->pWhere, 0); if( subqueryIsAgg ){ assert( pParent->pHaving==0 ); pParent->pHaving = pParent->pWhere; pParent->pWhere = pWhere; pParent->pHaving = sqlite3ExprAnd(db, pParent->pHaving, sqlite3ExprDup(db, pSub->pHaving, 0)); assert( pParent->pGroupBy==0 ); pParent->pGroupBy = sqlite3ExprListDup(db, pSub->pGroupBy, 0); }else{ pParent->pWhere = sqlite3ExprAnd(db, pParent->pWhere, pWhere); } substSelect(db, pParent, iParent, pSub->pEList, 0); /* The flattened query is distinct if either the inner or the ** outer query is distinct. */ pParent->selFlags |= pSub->selFlags & SF_Distinct; /* |
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Changes to test/tabfunc01.test.
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71 72 73 74 75 76 77 78 | } {1 {'v2' is not a function}} do_execsql_test tabfunc01-2.1 { CREATE TABLE t1(x); INSERT INTO t1(x) VALUES(2),(3); SELECT *, '|' FROM t1, generate_series(1,x) ORDER BY 1, 2 } {2 1 | 2 2 | 3 1 | 3 2 | 3 3 |} | > > > > | | 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 | } {1 {'v2' is not a function}} do_execsql_test tabfunc01-2.1 { CREATE TABLE t1(x); INSERT INTO t1(x) VALUES(2),(3); SELECT *, '|' FROM t1, generate_series(1,x) ORDER BY 1, 2 } {2 1 | 2 2 | 3 1 | 3 2 | 3 3 |} do_execsql_test tabfunc01-2.2 { SELECT *, '|' FROM (SELECT x FROM t1) AS y, generate_series(1,y.x) ORDER BY 1, 2; } {2 1 | 2 2 | 3 1 | 3 2 | 3 3 |} do_execsql_test tabfunc01-2.50 { SELECT * FROM generate_series() LIMIT 5; } {0 1 2 3 4} do_execsql_test tabfunc01-3.1 { SELECT DISTINCT value FROM generate_series(1,x), t1 ORDER BY 1; } {1 2 3} |
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