From 1be62b532b441aaff4b2d9c9dc028b96c4b7a8c7 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Tue, 31 Jul 2007 19:53:50 +0000 Subject: [PATCH] Fix a bug in the original implementation of redundant-join-clause removal: clauses in which one side or the other references both sides of the join cannot be removed as redundant, because that expression won't have been constrained below the join. Per report from Sergey Burladyan. --- src/backend/optimizer/path/indxpath.c | 4 ++- src/backend/optimizer/plan/createplan.c | 10 ++++--- src/backend/optimizer/util/relnode.c | 4 ++- src/backend/optimizer/util/restrictinfo.c | 32 ++++++++++++++++++++--- src/include/optimizer/restrictinfo.h | 6 ++++- src/test/regress/expected/join.out | 16 ++++++++++++ src/test/regress/expected/join_1.out | 16 ++++++++++++ src/test/regress/sql/join.sql | 16 ++++++++++++ 8 files changed, 95 insertions(+), 9 deletions(-) diff --git a/src/backend/optimizer/path/indxpath.c b/src/backend/optimizer/path/indxpath.c index 379e15a9641..f35372ebbef 100644 --- a/src/backend/optimizer/path/indxpath.c +++ b/src/backend/optimizer/path/indxpath.c @@ -9,7 +9,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/optimizer/path/indxpath.c,v 1.212.2.2 2007/05/22 01:40:42 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/optimizer/path/indxpath.c,v 1.212.2.3 2007/07/31 19:53:49 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -1755,6 +1755,8 @@ find_clauses_for_join(PlannerInfo *root, RelOptInfo *rel, { clause_list = remove_redundant_join_clauses(root, clause_list, + outer_relids, + rel->relids, isouterjoin); } diff --git a/src/backend/optimizer/plan/createplan.c b/src/backend/optimizer/plan/createplan.c index 14f1f1a10f4..75b67e8879f 100644 --- a/src/backend/optimizer/plan/createplan.c +++ b/src/backend/optimizer/plan/createplan.c @@ -10,7 +10,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/optimizer/plan/createplan.c,v 1.217 2006/10/04 00:29:54 momjian Exp $ + * $PostgreSQL: pgsql/src/backend/optimizer/plan/createplan.c,v 1.217.2.1 2007/07/31 19:53:49 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -1398,7 +1398,9 @@ create_nestloop_plan(PlannerInfo *root, select_nonredundant_join_clauses(root, joinrestrictclauses, innerpath->indexclauses, - IS_OUTER_JOIN(best_path->jointype)); + best_path->outerjoinpath->parent->relids, + best_path->innerjoinpath->parent->relids, + IS_OUTER_JOIN(best_path->jointype)); } } else if (IsA(best_path->innerjoinpath, BitmapHeapPath)) @@ -1430,7 +1432,9 @@ create_nestloop_plan(PlannerInfo *root, select_nonredundant_join_clauses(root, joinrestrictclauses, bitmapclauses, - IS_OUTER_JOIN(best_path->jointype)); + best_path->outerjoinpath->parent->relids, + best_path->innerjoinpath->parent->relids, + IS_OUTER_JOIN(best_path->jointype)); } } diff --git a/src/backend/optimizer/util/relnode.c b/src/backend/optimizer/util/relnode.c index 4d5bffdb7b1..2a3a14ae6b1 100644 --- a/src/backend/optimizer/util/relnode.c +++ b/src/backend/optimizer/util/relnode.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/optimizer/util/relnode.c,v 1.83 2006/10/04 00:29:55 momjian Exp $ + * $PostgreSQL: pgsql/src/backend/optimizer/util/relnode.c,v 1.83.2.1 2007/07/31 19:53:50 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -515,6 +515,8 @@ build_joinrel_restrictlist(PlannerInfo *root, * omit the redundant clause from the result list. */ result = remove_redundant_join_clauses(root, rlist, + outer_rel->relids, + inner_rel->relids, IS_OUTER_JOIN(jointype)); list_free(rlist); diff --git a/src/backend/optimizer/util/restrictinfo.c b/src/backend/optimizer/util/restrictinfo.c index 9176ae1680c..ae114f65509 100644 --- a/src/backend/optimizer/util/restrictinfo.c +++ b/src/backend/optimizer/util/restrictinfo.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/optimizer/util/restrictinfo.c,v 1.49 2006/10/04 00:29:55 momjian Exp $ + * $PostgreSQL: pgsql/src/backend/optimizer/util/restrictinfo.c,v 1.49.2.1 2007/07/31 19:53:50 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -36,6 +36,8 @@ static Expr *make_sub_restrictinfos(Expr *clause, static RestrictInfo *join_clause_is_redundant(PlannerInfo *root, RestrictInfo *rinfo, List *reference_list, + Relids outer_relids, + Relids inner_relids, bool isouterjoin); @@ -546,6 +548,8 @@ extract_actual_join_clauses(List *restrictinfo_list, */ List * remove_redundant_join_clauses(PlannerInfo *root, List *restrictinfo_list, + Relids outer_relids, + Relids inner_relids, bool isouterjoin) { List *result = NIL; @@ -572,7 +576,9 @@ remove_redundant_join_clauses(PlannerInfo *root, List *restrictinfo_list, RestrictInfo *prevrinfo; /* is it redundant with any prior clause? */ - prevrinfo = join_clause_is_redundant(root, rinfo, result, isouterjoin); + prevrinfo = join_clause_is_redundant(root, rinfo, result, + outer_relids, inner_relids, + isouterjoin); if (prevrinfo == NULL) { /* no, so add it to result list */ @@ -608,6 +614,8 @@ List * select_nonredundant_join_clauses(PlannerInfo *root, List *restrictinfo_list, List *reference_list, + Relids outer_relids, + Relids inner_relids, bool isouterjoin) { List *result = NIL; @@ -618,7 +626,9 @@ select_nonredundant_join_clauses(PlannerInfo *root, RestrictInfo *rinfo = (RestrictInfo *) lfirst(item); /* drop it if redundant with any reference clause */ - if (join_clause_is_redundant(root, rinfo, reference_list, isouterjoin) != NULL) + if (join_clause_is_redundant(root, rinfo, reference_list, + outer_relids, inner_relids, + isouterjoin) != NULL) continue; /* otherwise, add it to result list */ @@ -651,6 +661,12 @@ select_nonredundant_join_clauses(PlannerInfo *root, * of the latter, even though they might seem redundant by the pathkey * membership test. * + * Also, we cannot eliminate clauses wherein one side mentions vars from + * both relations, as in "WHERE t1.f1 = t2.f1 AND t1.f1 = t1.f2 - t2.f2". + * In this example, "t1.f2 - t2.f2" could not have been computed at all + * before forming the join of t1 and t2, so it certainly wasn't constrained + * earlier. + * * Weird special case: if we have two clauses that seem redundant * except one is pushed down into an outer join and the other isn't, * then they're not really redundant, because one constrains the @@ -660,6 +676,8 @@ static RestrictInfo * join_clause_is_redundant(PlannerInfo *root, RestrictInfo *rinfo, List *reference_list, + Relids outer_relids, + Relids inner_relids, bool isouterjoin) { ListCell *refitem; @@ -681,6 +699,14 @@ join_clause_is_redundant(PlannerInfo *root, bms_is_empty(rinfo->right_relids)) return NULL; /* var = const, so not redundant */ + /* check for either side mentioning both rels */ + if (bms_overlap(rinfo->left_relids, outer_relids) && + bms_overlap(rinfo->left_relids, inner_relids)) + return NULL; /* clause LHS uses both, so not redundant */ + if (bms_overlap(rinfo->right_relids, outer_relids) && + bms_overlap(rinfo->right_relids, inner_relids)) + return NULL; /* clause RHS uses both, so not redundant */ + cache_mergeclause_pathkeys(root, rinfo); foreach(refitem, reference_list) diff --git a/src/include/optimizer/restrictinfo.h b/src/include/optimizer/restrictinfo.h index db24c4989db..c9639a2c059 100644 --- a/src/include/optimizer/restrictinfo.h +++ b/src/include/optimizer/restrictinfo.h @@ -7,7 +7,7 @@ * Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * - * $PostgreSQL: pgsql/src/include/optimizer/restrictinfo.h,v 1.38 2006/10/04 00:30:09 momjian Exp $ + * $PostgreSQL: pgsql/src/include/optimizer/restrictinfo.h,v 1.38.2.1 2007/07/31 19:53:50 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -34,10 +34,14 @@ extern void extract_actual_join_clauses(List *restrictinfo_list, List **otherquals); extern List *remove_redundant_join_clauses(PlannerInfo *root, List *restrictinfo_list, + Relids outer_relids, + Relids inner_relids, bool isouterjoin); extern List *select_nonredundant_join_clauses(PlannerInfo *root, List *restrictinfo_list, List *reference_list, + Relids outer_relids, + Relids inner_relids, bool isouterjoin); #endif /* RESTRICTINFO_H */ diff --git a/src/test/regress/expected/join.out b/src/test/regress/expected/join.out index 8b6716def81..3b7bdd9cbb3 100644 --- a/src/test/regress/expected/join.out +++ b/src/test/regress/expected/join.out @@ -2250,3 +2250,19 @@ WHERE d.f1 IS NULL; 9999 (3 rows) +-- +-- regression test for problems of the sort depicted in bug #3494 +-- +create temp table tt5(f1 int, f2 int); +create temp table tt6(f1 int, f2 int); +insert into tt5 values(1, 10); +insert into tt5 values(1, 11); +insert into tt6 values(1, 9); +insert into tt6 values(1, 2); +insert into tt6 values(2, 9); +select * from tt5,tt6 where tt5.f1 = tt6.f1 and tt5.f1 = tt5.f2 - tt6.f2; + f1 | f2 | f1 | f2 +----+----+----+---- + 1 | 10 | 1 | 9 +(1 row) + diff --git a/src/test/regress/expected/join_1.out b/src/test/regress/expected/join_1.out index 8e7e4de0141..f1bf4b9af26 100644 --- a/src/test/regress/expected/join_1.out +++ b/src/test/regress/expected/join_1.out @@ -2250,3 +2250,19 @@ WHERE d.f1 IS NULL; 9999 (3 rows) +-- +-- regression test for problems of the sort depicted in bug #3494 +-- +create temp table tt5(f1 int, f2 int); +create temp table tt6(f1 int, f2 int); +insert into tt5 values(1, 10); +insert into tt5 values(1, 11); +insert into tt6 values(1, 9); +insert into tt6 values(1, 2); +insert into tt6 values(2, 9); +select * from tt5,tt6 where tt5.f1 = tt6.f1 and tt5.f1 = tt5.f2 - tt6.f2; + f1 | f2 | f1 | f2 +----+----+----+---- + 1 | 10 | 1 | 9 +(1 row) + diff --git a/src/test/regress/sql/join.sql b/src/test/regress/sql/join.sql index d3433effd11..ad8957cd6e3 100644 --- a/src/test/regress/sql/join.sql +++ b/src/test/regress/sql/join.sql @@ -424,3 +424,19 @@ LEFT JOIN ( WHERE c.f1 IS NULL ) AS d ON (a.f1 = d.f1) WHERE d.f1 IS NULL; + +-- +-- regression test for problems of the sort depicted in bug #3494 +-- + +create temp table tt5(f1 int, f2 int); +create temp table tt6(f1 int, f2 int); + +insert into tt5 values(1, 10); +insert into tt5 values(1, 11); + +insert into tt6 values(1, 9); +insert into tt6 values(1, 2); +insert into tt6 values(2, 9); + +select * from tt5,tt6 where tt5.f1 = tt6.f1 and tt5.f1 = tt5.f2 - tt6.f2;