diff options
Diffstat (limited to 'src/backend/optimizer/path/joinpath.c')
| -rw-r--r-- | src/backend/optimizer/path/joinpath.c | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/src/backend/optimizer/path/joinpath.c b/src/backend/optimizer/path/joinpath.c index f69ffbed7a8..2e208cb6210 100644 --- a/src/backend/optimizer/path/joinpath.c +++ b/src/backend/optimizer/path/joinpath.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/optimizer/path/joinpath.c,v 1.128 2010/01/02 16:57:46 momjian Exp $ + * $PostgreSQL: pgsql/src/backend/optimizer/path/joinpath.c,v 1.129 2010/01/05 23:25:36 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -1184,10 +1184,18 @@ select_mergejoin_clauses(PlannerInfo *root, if (isouterjoin && restrictinfo->is_pushed_down) continue; + /* Check that clause is a mergeable operator clause */ if (!restrictinfo->can_join || restrictinfo->mergeopfamilies == NIL) { - have_nonmergeable_joinclause = true; + /* + * The executor can handle extra joinquals that are constants, + * but not anything else, when doing right/full merge join. (The + * reason to support constants is so we can do FULL JOIN ON + * FALSE.) + */ + if (!restrictinfo->clause || !IsA(restrictinfo->clause, Const)) + have_nonmergeable_joinclause = true; continue; /* not mergejoinable */ } |