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Overview
Comment: | Avoid creating an automatic index on the RHS of a LEFT JOIN to optimize an IS term. Fix for [ce68383b]. |
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Downloads: | Tarball | ZIP archive |
Timelines: | family | ancestors | descendants | both | trunk |
Files: | files | file ages | folders |
SHA3-256: |
d2f0b2e859a8a413ee4e4bd7040e450c |
User & Date: | dan 2017-07-18 17:13:41.139 |
Context
2017-07-18
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17:34 | Do not use the flattening optimization for a sub-query on the RHS of a LEFT JOIN if that subquery reads data from a virtual table. Because it prevents the planner from creating an automatic index on the results of the sub-query, the flattening optimization sometimes slows things down in this case. (check-in: 9dbae1df75 user: dan tags: trunk) | |
17:13 | Avoid creating an automatic index on the RHS of a LEFT JOIN to optimize an IS term. Fix for [ce68383b]. (check-in: d2f0b2e859 user: dan tags: trunk) | |
14:41 | Change the default command-line shell history depth to 2000 lines. (check-in: 0b69aa7e37 user: drh tags: trunk) | |
Changes
Changes to src/where.c.
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604 605 606 607 608 609 610 611 612 613 614 615 616 617 | 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; } | > > > > > > > > > | 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 | 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( (pSrc->fg.jointype & JT_LEFT) && !ExprHasProperty(pTerm->pExpr, EP_FromJoin) && (pTerm->eOperator & WO_IS) ){ /* Cannot use an IS term from the WHERE clause as an index driver for ** the RHS of a LEFT JOIN. Such a term can only be used if it is from ** the ON clause. */ 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; } |
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Changes to test/autoindex1.test.
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515 516 517 518 519 520 521 522 523 | # 2015-04-15: A NULL CollSeq pointer in automatic index creation. # do_execsql_test autoindex1-920 { CREATE TABLE t920(x); INSERT INTO t920 VALUES(3),(4),(5); SELECT * FROM t920,(SELECT 0 FROM t920),(VALUES(9)) WHERE 5 IN (x); } {5 0 9 5 0 9 5 0 9} finish_test | > > > > > > > > > > > > > > > > > > | 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 | # 2015-04-15: A NULL CollSeq pointer in automatic index creation. # do_execsql_test autoindex1-920 { CREATE TABLE t920(x); INSERT INTO t920 VALUES(3),(4),(5); SELECT * FROM t920,(SELECT 0 FROM t920),(VALUES(9)) WHERE 5 IN (x); } {5 0 9 5 0 9 5 0 9} #------------------------------------------------------------------------- # An IS term from the WHERE clause of a LEFT JOIN cannot be used as an # index driver for the RHS of a LEFT JOIN. Prior to this being fixed, # the following SELECT count(*) would incorrectly return 1. # do_execsql_test autoindex1-1010 { CREATE TABLE t11(w); CREATE TABLE t12(y); INSERT INTO t11 VALUES(NULL); INSERT INTO t12 VALUES('notnull'); } do_execsql_test autoindex1-1020 { SELECT count(*) FROM t11 LEFT JOIN t12 WHERE t12.y IS t11.w; } 0 finish_test |