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| author | Tom Lane <tgl@sss.pgh.pa.us> | 2000-11-23 03:57:31 +0000 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2000-11-23 03:57:31 +0000 |
| commit | 48437f5c3af2c6a64ef468a3cdd15f674b7e219f (patch) | |
| tree | 405247bb5e6162c65cd30ce04bb5c083319c63af /src | |
| parent | 5479c11bfa3be21afca44ef59e2e14204bc0a142 (diff) | |
| download | postgresql-48437f5c3af2c6a64ef468a3cdd15f674b7e219f.tar.gz postgresql-48437f5c3af2c6a64ef468a3cdd15f674b7e219f.zip | |
Ensure that mergejoin plan will be considered for FULL OUTER JOIN even
if enable_mergejoin = OFF. Must do this, because we have no other
implementation method for full joins.
Diffstat (limited to 'src')
| -rw-r--r-- | src/backend/optimizer/path/joinpath.c | 9 | ||||
| -rw-r--r-- | src/backend/optimizer/plan/initsplan.c | 10 |
2 files changed, 13 insertions, 6 deletions
diff --git a/src/backend/optimizer/path/joinpath.c b/src/backend/optimizer/path/joinpath.c index 0dbfef8b2fc..6096f8c3f26 100644 --- a/src/backend/optimizer/path/joinpath.c +++ b/src/backend/optimizer/path/joinpath.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/optimizer/path/joinpath.c,v 1.58 2000/10/05 19:48:26 momjian Exp $ + * $Header: /cvsroot/pgsql/src/backend/optimizer/path/joinpath.c,v 1.59 2000/11/23 03:57:31 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -75,9 +75,12 @@ add_paths_to_joinrel(Query *root, List *mergeclause_list = NIL; /* - * Find potential mergejoin clauses. + * Find potential mergejoin clauses. We can skip this if we are not + * interested in doing a mergejoin. However, mergejoin is currently + * our only way of implementing full outer joins, so override + * mergejoin disable if it's a full join. */ - if (enable_mergejoin) + if (enable_mergejoin || jointype == JOIN_FULL) mergeclause_list = select_mergejoin_clauses(joinrel, outerrel, innerrel, diff --git a/src/backend/optimizer/plan/initsplan.c b/src/backend/optimizer/plan/initsplan.c index 3bea06e2af6..ee037c750b6 100644 --- a/src/backend/optimizer/plan/initsplan.c +++ b/src/backend/optimizer/plan/initsplan.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/optimizer/plan/initsplan.c,v 1.52 2000/11/16 22:30:25 tgl Exp $ + * $Header: /cvsroot/pgsql/src/backend/optimizer/plan/initsplan.c,v 1.53 2000/11/23 03:57:31 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -454,9 +454,13 @@ distribute_qual_to_rels(Query *root, Node *clause, * joining. * * We don't bother setting the merge/hashjoin info if we're not - * going to need it. + * going to need it. We do want to know about mergejoinable ops + * in any potential equijoin clause (see later in this routine), + * and we ignore enable_mergejoin if isouterjoin is true, because + * mergejoin is the only implementation we have for full and right + * outer joins. */ - if (enable_mergejoin || can_be_equijoin) + if (enable_mergejoin || isouterjoin || can_be_equijoin) check_mergejoinable(restrictinfo); if (enable_hashjoin) check_hashjoinable(restrictinfo); |