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Changes In Branch push-down-backport Excluding Merge-Ins
This is equivalent to a diff from d227de8a to adc082c1
2017-07-17
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19:37 | Try to push relevant WHERE clause terms of the outer query down into the subquery in order to help the subquery run faster and/or use less memory. This is a cherry-pick of [6df18e949d36] with bug fixes. (check-in: cd6ac078 user: drh tags: branch-3.8.9) | |
19:25 | When checking for the WHERE-clause push-down optimization, verify that all terms of the compound inner SELECT are non-aggregate, not just the last term. Fix for ticket [f7f8c97e97597]. (Closed-Leaf check-in: adc082c1 user: drh tags: push-down-backport) | |
19:14 | Do not apply the WHERE-clause pushdown optimization to terms that originate in the ON or USING clause of a LEFT JOIN. Fix for ticket [c2a19d81652f40568c]. (check-in: 52674f94 user: drh tags: push-down-backport) | |
19:07 | For FROM-clause subqueries that cannot be flattened, try to push relevant WHERE clause terms of the outer query down into the subquery in order to help the subquery run faster and/or use less memory. Cherry-pick from [6df18e949d36]. Still need to backport bug fixes associated with that check-in. (check-in: 043d6ce8 user: drh tags: push-down-backport) | |
2017-07-08
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01:01 | Fix the covering index OR optimization (check-in [fcbd6abd]) so that it works with SQLITE_MAX_ATTACHED>30. Broken by a bad cherry-pick merge. (check-in: d227de8a user: drh tags: branch-3.8.9) | |
2017-07-05
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16:20 | Make use of covering indexes in the OR optimization. (check-in: fcbd6abd user: drh tags: branch-3.8.9) | |
2016-04-25
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02:20 | When checking for the WHERE-clause push-down optimization, verify that all terms of the compound inner SELECT are non-aggregate, not just the last term. Fix for ticket [f7f8c97e97597]. (check-in: ec215f94 user: drh tags: trunk) | |
Changes to src/select.c.
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3745 3746 3747 3748 3749 3750 3751 3752 3753 3754 3755 3756 3757 3758 | } #endif return 1; } #endif /* !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW) */ /* ** Based on the contents of the AggInfo structure indicated by the first ** argument, this function checks if the following are true: ** ** * the query contains just a single aggregate function, ** * the aggregate function is either min() or max(), and ** * the argument to the aggregate function is a column value. | > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > | 3745 3746 3747 3748 3749 3750 3751 3752 3753 3754 3755 3756 3757 3758 3759 3760 3761 3762 3763 3764 3765 3766 3767 3768 3769 3770 3771 3772 3773 3774 3775 3776 3777 3778 3779 3780 3781 3782 3783 3784 3785 3786 3787 3788 3789 3790 3791 3792 3793 3794 3795 3796 3797 3798 3799 3800 3801 3802 3803 3804 3805 3806 3807 3808 3809 3810 3811 3812 3813 3814 3815 3816 3817 3818 3819 3820 3821 3822 3823 3824 3825 3826 3827 3828 3829 3830 3831 3832 3833 3834 3835 | } #endif return 1; } #endif /* !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW) */ #if !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW) /* ** Make copies of relevant WHERE clause terms of the outer query into ** the WHERE clause of subquery. Example: ** ** SELECT * FROM (SELECT a AS x, c-d AS y FROM t1) WHERE x=5 AND y=10; ** ** Transformed into: ** ** SELECT * FROM (SELECT a AS x, c-d AS y FROM t1 WHERE a=5 AND c-d=10) ** WHERE x=5 AND y=10; ** ** The hope is that the terms added to the inner query will make it more ** efficient. ** ** Do not attempt this optimization if: ** ** (1) The inner query is an aggregate. (In that case, we'd really want ** to copy the outer WHERE-clause terms onto the HAVING clause of the ** inner query. But they probably won't help there so do not bother.) ** ** (2) The inner query is the recursive part of a common table expression. ** ** (3) The inner query has a LIMIT clause (since the changes to the WHERE ** close would change the meaning of the LIMIT). ** ** (4) The inner query is the right operand of a LEFT JOIN. (The caller ** enforces this restriction since this routine does not have enough ** information to know.) ** ** (5) The WHERE clause expression originates in the ON or USING clause ** of a LEFT JOIN. ** ** Return 0 if no changes are made and non-zero if one or more WHERE clause ** terms are duplicated into the subquery. */ static int pushDownWhereTerms( sqlite3 *db, /* The database connection (for malloc()) */ Select *pSubq, /* The subquery whose WHERE clause is to be augmented */ Expr *pWhere, /* The WHERE clause of the outer query */ int iCursor /* Cursor number of the subquery */ ){ Expr *pNew; int nChng = 0; Select *pX; /* For looping over compound SELECTs in pSubq */ if( pWhere==0 ) return 0; for(pX=pSubq; pX; pX=pX->pPrior){ if( (pX->selFlags & (SF_Aggregate|SF_Recursive))!=0 ){ testcase( pX->selFlags & SF_Aggregate ); testcase( pX->selFlags & SF_Recursive ); testcase( pX!=pSubq ); return 0; /* restrictions (1) and (2) */ } } if( pSubq->pLimit!=0 ){ return 0; /* restriction (3) */ } while( pWhere->op==TK_AND ){ nChng += pushDownWhereTerms(db, pSubq, pWhere->pRight, iCursor); pWhere = pWhere->pLeft; } if( ExprHasProperty(pWhere,EP_FromJoin) ) return 0; /* restriction 5 */ if( sqlite3ExprIsTableConstant(pWhere, iCursor) ){ nChng++; while( pSubq ){ pNew = sqlite3ExprDup(db, pWhere, 0); pNew = substExpr(db, pNew, iCursor, pSubq->pEList); pSubq->pWhere = sqlite3ExprAnd(db, pSubq->pWhere, pNew); pSubq = pSubq->pPrior; } } return nChng; } #endif /* !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW) */ /* ** Based on the contents of the AggInfo structure indicated by the first ** argument, this function checks if the following are true: ** ** * the query contains just a single aggregate function, ** * the aggregate function is either min() or max(), and ** * the argument to the aggregate function is a column value. |
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4936 4937 4938 4939 4940 4941 4942 | if( flattenSubquery(pParse, p, i, isAgg, isAggSub) ){ /* This subquery can be absorbed into its parent. */ if( isAggSub ){ isAgg = 1; p->selFlags |= SF_Aggregate; } i = -1; | > > > > > > > > > > > | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | > | | 5013 5014 5015 5016 5017 5018 5019 5020 5021 5022 5023 5024 5025 5026 5027 5028 5029 5030 5031 5032 5033 5034 5035 5036 5037 5038 5039 5040 5041 5042 5043 5044 5045 5046 5047 5048 5049 5050 5051 5052 5053 5054 5055 5056 5057 5058 5059 5060 5061 5062 5063 5064 5065 5066 5067 5068 5069 5070 5071 5072 5073 5074 5075 5076 5077 5078 5079 5080 5081 5082 5083 5084 5085 5086 5087 5088 5089 5090 5091 | if( flattenSubquery(pParse, p, i, isAgg, isAggSub) ){ /* This subquery can be absorbed into its parent. */ if( isAggSub ){ isAgg = 1; p->selFlags |= SF_Aggregate; } i = -1; }else{ if( (pItem->jointype & JT_OUTER)==0 && pushDownWhereTerms(db, pSub, p->pWhere, pItem->iCursor) ){ #if SELECTTRACE_ENABLED if( sqlite3SelectTrace & 0x100 ){ sqlite3DebugPrintf("After WHERE-clause push-down:\n"); sqlite3TreeViewSelect(0, p, 0); } #endif } if( pTabList->nSrc==1 && OptimizationEnabled(db, SQLITE_SubqCoroutine) ){ /* Implement a co-routine that will return a single row of the result ** set on each invocation. */ int addrTop = sqlite3VdbeCurrentAddr(v)+1; pItem->regReturn = ++pParse->nMem; sqlite3VdbeAddOp3(v, OP_InitCoroutine, pItem->regReturn, 0, addrTop); VdbeComment((v, "%s", pItem->pTab->zName)); pItem->addrFillSub = addrTop; sqlite3SelectDestInit(&dest, SRT_Coroutine, pItem->regReturn); explainSetInteger(pItem->iSelectId, (u8)pParse->iNextSelectId); sqlite3Select(pParse, pSub, &dest); pItem->pTab->nRowLogEst = sqlite3LogEst(pSub->nSelectRow); pItem->viaCoroutine = 1; pItem->regResult = dest.iSdst; sqlite3VdbeAddOp1(v, OP_EndCoroutine, pItem->regReturn); sqlite3VdbeJumpHere(v, addrTop-1); sqlite3ClearTempRegCache(pParse); }else{ /* Generate a subroutine that will fill an ephemeral table with ** the content of this subquery. pItem->addrFillSub will point ** to the address of the generated subroutine. pItem->regReturn ** is a register allocated to hold the subroutine return address */ int topAddr; int onceAddr = 0; int retAddr; assert( pItem->addrFillSub==0 ); pItem->regReturn = ++pParse->nMem; topAddr = sqlite3VdbeAddOp2(v, OP_Integer, 0, pItem->regReturn); pItem->addrFillSub = topAddr+1; if( pItem->isCorrelated==0 ){ /* If the subquery is not correlated and if we are not inside of ** a trigger, then we only need to compute the value of the subquery ** once. */ onceAddr = sqlite3CodeOnce(pParse); VdbeCoverage(v); VdbeComment((v, "materialize \"%s\"", pItem->pTab->zName)); }else{ VdbeNoopComment((v, "materialize \"%s\"", pItem->pTab->zName)); } sqlite3SelectDestInit(&dest, SRT_EphemTab, pItem->iCursor); explainSetInteger(pItem->iSelectId, (u8)pParse->iNextSelectId); sqlite3Select(pParse, pSub, &dest); pItem->pTab->nRowLogEst = sqlite3LogEst(pSub->nSelectRow); if( onceAddr ) sqlite3VdbeJumpHere(v, onceAddr); retAddr = sqlite3VdbeAddOp1(v, OP_Return, pItem->regReturn); VdbeComment((v, "end %s", pItem->pTab->zName)); sqlite3VdbeChangeP1(v, topAddr, retAddr); sqlite3ClearTempRegCache(pParse); } } if( db->mallocFailed ){ goto select_end; } pParse->nHeight -= sqlite3SelectExprHeight(p); pTabList = p->pSrc; if( !IgnorableOrderby(pDest) ){ sSort.pOrderBy = p->pOrderBy; } |
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Changes to test/join5.test.
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156 157 158 159 160 161 162 163 164 | CREATE TABLE x2(b NOT NULL); CREATE TABLE x3(c, d); INSERT INTO x3 VALUES('a', NULL); INSERT INTO x3 VALUES('b', NULL); INSERT INTO x3 VALUES('c', NULL); SELECT * FROM x1 LEFT JOIN x2 JOIN x3 WHERE x3.d = x2.b; } {} finish_test | > > > > > > > > > > > > > > > > > > > > > > > | 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 | CREATE TABLE x2(b NOT NULL); CREATE TABLE x3(c, d); INSERT INTO x3 VALUES('a', NULL); INSERT INTO x3 VALUES('b', NULL); INSERT INTO x3 VALUES('c', NULL); SELECT * FROM x1 LEFT JOIN x2 JOIN x3 WHERE x3.d = x2.b; } {} # Ticket https://www.sqlite.org/src/tktview/c2a19d81652f40568c770c43 on # 2015-08-20. LEFT JOIN and the push-down optimization. # do_execsql_test join6-4.1 { SELECT * FROM ( SELECT 'apple' fruit UNION ALL SELECT 'banana' ) a JOIN ( SELECT 'apple' fruit UNION ALL SELECT 'banana' ) b ON a.fruit=b.fruit LEFT JOIN ( SELECT 1 isyellow ) c ON b.fruit='banana'; } {apple apple {} banana banana 1} do_execsql_test join6-4.2 { SELECT * FROM (SELECT 'apple' fruit UNION ALL SELECT 'banana') LEFT JOIN (SELECT 1) ON fruit='banana'; } {apple {} banana 1} finish_test |
Changes to test/select4.test.
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859 860 861 862 863 864 865 866 867 | } {} do_execsql_test select4-14.8 { SELECT * FROM t14 EXCEPT VALUES('a','b','c') EXCEPT VALUES(4,5,6) } {1 2 3} do_execsql_test select4-14.9 { SELECT * FROM t14 UNION ALL VALUES(3,2,1),(2,3,1),(1,2,3),(2,1,3); } {1 2 3 4 5 6 3 2 1 2 3 1 1 2 3 2 1 3} finish_test | > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > | 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 | } {} do_execsql_test select4-14.8 { SELECT * FROM t14 EXCEPT VALUES('a','b','c') EXCEPT VALUES(4,5,6) } {1 2 3} do_execsql_test select4-14.9 { SELECT * FROM t14 UNION ALL VALUES(3,2,1),(2,3,1),(1,2,3),(2,1,3); } {1 2 3 4 5 6 3 2 1 2 3 1 1 2 3 2 1 3} # Ticket https://www.sqlite.org/src/tktview/f7f8c97e975978d45 on 2016-04-25 # # The where push-down optimization from 2015-06-02 is suppose to disable # on aggregate subqueries. But if the subquery is a compound where the # last SELECT is non-aggregate but some other SELECT is an aggregate, the # test is incomplete and the optimization is not properly disabled. # # The following test cases verify that the fix works. # do_execsql_test select4-17.1 { DROP TABLE IF EXISTS t1; CREATE TABLE t1(a int, b int); INSERT INTO t1 VALUES(1,2),(1,18),(2,19); SELECT x, y FROM ( SELECT 98 AS x, 99 AS y UNION SELECT a AS x, sum(b) AS y FROM t1 GROUP BY a ) AS w WHERE y>=20 ORDER BY +x; } {1 20 98 99} do_execsql_test select4-17.2 { SELECT x, y FROM ( SELECT a AS x, sum(b) AS y FROM t1 GROUP BY a UNION SELECT 98 AS x, 99 AS y ) AS w WHERE y>=20 ORDER BY +x; } {1 20 98 99} do_catchsql_test select4-17.3 { SELECT x, y FROM ( SELECT a AS x, sum(b) AS y FROM t1 GROUP BY a LIMIT 3 UNION SELECT 98 AS x, 99 AS y ) AS w WHERE y>=20 ORDER BY +x; } {1 {LIMIT clause should come after UNION not before}} finish_test |