diff options
Diffstat (limited to 'src/backend/optimizer/path/joinpath.c')
| -rw-r--r-- | src/backend/optimizer/path/joinpath.c | 19 |
1 files changed, 17 insertions, 2 deletions
diff --git a/src/backend/optimizer/path/joinpath.c b/src/backend/optimizer/path/joinpath.c index 35c9353d2e2..f069f13fefb 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 1.130 2010/02/26 02:00:44 momjian Exp $ + * $PostgreSQL: pgsql/src/backend/optimizer/path/joinpath.c,v 1.131 2010/03/22 13:57:15 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -192,7 +192,9 @@ clause_sides_match_join(RestrictInfo *rinfo, RelOptInfo *outerrel, * * This is true for a left join for which the join condition cannot match * more than one inner-side row. (There are other possibly interesting - * cases, but we don't have the infrastructure to prove them.) + * cases, but we don't have the infrastructure to prove them.) We also + * have to check that the inner side doesn't generate any variables needed + * above the join. * * Note: there is no need to consider the symmetrical case of duplicating the * right input, because add_paths_to_joinrel() will be called with each rel @@ -246,6 +248,19 @@ join_is_removable(PlannerInfo *root, } /* + * Similarly check that the inner rel doesn't produce any PlaceHolderVars + * that will be used above the join. + */ + foreach(l, root->placeholder_list) + { + PlaceHolderInfo *phinfo = (PlaceHolderInfo *) lfirst(l); + + if (bms_is_subset(phinfo->ph_eval_at, innerrel->relids) && + !bms_is_subset(phinfo->ph_needed, joinrel->relids)) + return false; + } + + /* * Search for mergejoinable clauses that constrain the inner rel against * either the outer rel or a pseudoconstant. If an operator is * mergejoinable then it behaves like equality for some btree opclass, so |