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Overview
Comment: | Improvements to the HAVING-to-WHERE optimization. The code uses less space and less CPU, and there is now ".selecttrace" output. |
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Downloads: | Tarball | ZIP archive |
Timelines: | family | ancestors | descendants | both | trunk |
Files: | files | file ages | folders |
SHA3-256: |
5ad668d4339397fe66fe085e0527e37a |
User & Date: | drh 2018-03-20 18:08:33.634 |
Context
2018-03-20
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19:02 | Fix incorrect testcase labels on two cases in join5.test. No changes to code. (check-in: 4661ac81c9 user: drh tags: trunk) | |
18:08 | Improvements to the HAVING-to-WHERE optimization. The code uses less space and less CPU, and there is now ".selecttrace" output. (check-in: 5ad668d433 user: drh tags: trunk) | |
16:56 | For 'zipfile', detect attempts to cause a duplicate entry via UPDATE. Also, fix handling of 'UPDATE OR REPLACE' statements run on zipfile virtual tables. Win32 portability fixes to the 'fileio' extension. Miscellaneous test fixes. (check-in: b36caeca91 user: mistachkin tags: trunk) | |
Changes
Changes to src/select.c.
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4908 4909 4910 4911 4912 4913 4914 | ); } } #else # define explainSimpleCount(a,b,c) #endif | < < < < < < < < | | | | > | 4908 4909 4910 4911 4912 4913 4914 4915 4916 4917 4918 4919 4920 4921 4922 4923 4924 4925 4926 4927 4928 4929 4930 4931 4932 4933 4934 4935 4936 4937 4938 4939 4940 4941 4942 4943 4944 | ); } } #else # define explainSimpleCount(a,b,c) #endif /* ** sqlite3WalkExpr() callback used by havingToWhere(). ** ** If the node passed to the callback is a TK_AND node, return ** WRC_Continue to tell sqlite3WalkExpr() to iterate through child nodes. ** ** Otherwise, return WRC_Prune. In this case, also check if the ** sub-expression matches the criteria for being moved to the WHERE ** clause. If so, add it to the WHERE clause and replace the sub-expression ** within the HAVING expression with a constant "1". */ static int havingToWhereExprCb(Walker *pWalker, Expr *pExpr){ if( pExpr->op!=TK_AND ){ Select *pS = pWalker->u.pSelect; if( sqlite3ExprIsConstantOrGroupBy(pWalker->pParse, pExpr, pS->pGroupBy) ){ sqlite3 *db = pWalker->pParse->db; Expr *pNew = sqlite3ExprAlloc(db, TK_INTEGER, &sqlite3IntTokens[1], 0); if( pNew ){ Expr *pWhere = pS->pWhere; SWAP(Expr, *pNew, *pExpr); pNew = sqlite3ExprAnd(db, pWhere, pNew); pS->pWhere = pNew; pWalker->eCode = 1; } } return WRC_Prune; } return WRC_Continue; } |
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4960 4961 4962 4963 4964 4965 4966 | ** ** SELECT * FROM <tables> WHERE a=? AND b=? GROUP BY b HAVING c=? ** ** A term of the HAVING expression is eligible for transfer if it consists ** entirely of constants and expressions that are also GROUP BY terms that ** use the "BINARY" collation sequence. */ | | < < < < < < < < < < | | > > > > > > | 4953 4954 4955 4956 4957 4958 4959 4960 4961 4962 4963 4964 4965 4966 4967 4968 4969 4970 4971 4972 4973 4974 4975 4976 4977 4978 4979 | ** ** SELECT * FROM <tables> WHERE a=? AND b=? GROUP BY b HAVING c=? ** ** A term of the HAVING expression is eligible for transfer if it consists ** entirely of constants and expressions that are also GROUP BY terms that ** use the "BINARY" collation sequence. */ static void havingToWhere(Parse *pParse, Select *p){ Walker sWalker; memset(&sWalker, 0, sizeof(sWalker)); sWalker.pParse = pParse; sWalker.xExprCallback = havingToWhereExprCb; sWalker.u.pSelect = p; sqlite3WalkExpr(&sWalker, p->pHaving); #if SELECTTRACE_ENABLED if( sWalker.eCode && (sqlite3SelectTrace & 0x100)!=0 ){ SELECTTRACE(0x100,pParse,p,("Move HAVING terms into WHERE:\n")); sqlite3TreeViewSelect(0, p, 0); } #endif } /* ** Check to see if the pThis entry of pTabList is a self-join of a prior view. ** If it is, then return the SrcList_item for the prior view. If it is not, ** then return 0. */ |
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5645 5646 5647 5648 5649 5650 5651 | sAggInfo.nSortingColumn = pGroupBy ? pGroupBy->nExpr : 0; sAggInfo.pGroupBy = pGroupBy; sqlite3ExprAnalyzeAggList(&sNC, pEList); sqlite3ExprAnalyzeAggList(&sNC, sSort.pOrderBy); if( pHaving ){ if( pGroupBy ){ assert( pWhere==p->pWhere ); | > > | | 5634 5635 5636 5637 5638 5639 5640 5641 5642 5643 5644 5645 5646 5647 5648 5649 5650 | sAggInfo.nSortingColumn = pGroupBy ? pGroupBy->nExpr : 0; sAggInfo.pGroupBy = pGroupBy; sqlite3ExprAnalyzeAggList(&sNC, pEList); sqlite3ExprAnalyzeAggList(&sNC, sSort.pOrderBy); if( pHaving ){ if( pGroupBy ){ assert( pWhere==p->pWhere ); assert( pHaving==p->pHaving ); assert( pGroupBy==p->pGroupBy ); havingToWhere(pParse, p); pWhere = p->pWhere; } sqlite3ExprAnalyzeAggregates(&sNC, pHaving); } sAggInfo.nAccumulator = sAggInfo.nColumn; if( p->pGroupBy==0 && p->pHaving==0 && sAggInfo.nFunc==1 ){ minMaxFlag = minMaxQuery(db, sAggInfo.aFunc[0].pExpr, &pMinMaxOrderBy); |
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Changes to src/sqliteInt.h.
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3353 3354 3355 3356 3357 3358 3359 | int n; /* A counter */ int iCur; /* A cursor number */ SrcList *pSrcList; /* FROM clause */ struct SrcCount *pSrcCount; /* Counting column references */ struct CCurHint *pCCurHint; /* Used by codeCursorHint() */ int *aiCol; /* array of column indexes */ struct IdxCover *pIdxCover; /* Check for index coverage */ | | | | 3353 3354 3355 3356 3357 3358 3359 3360 3361 3362 3363 3364 3365 3366 3367 3368 3369 | int n; /* A counter */ int iCur; /* A cursor number */ SrcList *pSrcList; /* FROM clause */ struct SrcCount *pSrcCount; /* Counting column references */ struct CCurHint *pCCurHint; /* Used by codeCursorHint() */ int *aiCol; /* array of column indexes */ struct IdxCover *pIdxCover; /* Check for index coverage */ struct IdxExprTrans *pIdxTrans; /* Convert idxed expr to column */ ExprList *pGroupBy; /* GROUP BY clause */ Select *pSelect; /* HAVING to WHERE clause ctx */ } u; }; /* Forward declarations */ int sqlite3WalkExpr(Walker*, Expr*); int sqlite3WalkExprList(Walker*, ExprList*); int sqlite3WalkSelect(Walker*, Select*); |
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