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| author | Tom Lane <tgl@sss.pgh.pa.us> | 2010-09-28 12:08:56 -0400 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2010-09-28 14:19:00 -0400 |
| commit | eb229505103eb5494c33832d422584bfdee03fc6 (patch) | |
| tree | ca7c12732d170cb5abef8f108b2d95f508444b7c /src/backend/optimizer/plan/analyzejoins.c | |
| parent | 9c5f4f6cb50dd22028acc0b6f20291a5edcac62b (diff) | |
| download | postgresql-eb229505103eb5494c33832d422584bfdee03fc6.tar.gz postgresql-eb229505103eb5494c33832d422584bfdee03fc6.zip | |
Fix PlaceHolderVar mechanism's interaction with outer joins.
The point of a PlaceHolderVar is to allow a non-strict expression to be
evaluated below an outer join, after which its value bubbles up like a Var
and can be forced to NULL when the outer join's semantics require that.
However, there was a serious design oversight in that, namely that we
didn't ensure that there was actually a correct place in the plan tree
to evaluate the placeholder :-(. It may be necessary to delay evaluation
of an outer join to ensure that a placeholder that should be evaluated
below the join can be evaluated there. Per recent bug report from Kirill
Simonov.
Back-patch to 8.4 where the PlaceHolderVar mechanism was introduced.
Diffstat (limited to 'src/backend/optimizer/plan/analyzejoins.c')
| -rw-r--r-- | src/backend/optimizer/plan/analyzejoins.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/src/backend/optimizer/plan/analyzejoins.c b/src/backend/optimizer/plan/analyzejoins.c index 2a913578eba..89805c36b06 100644 --- a/src/backend/optimizer/plan/analyzejoins.c +++ b/src/backend/optimizer/plan/analyzejoins.c @@ -396,6 +396,8 @@ remove_rel_from_query(PlannerInfo *root, int relid, Relids joinrelids) phinfo->ph_eval_at = bms_add_member(phinfo->ph_eval_at, relid); phinfo->ph_needed = bms_del_member(phinfo->ph_needed, relid); + /* ph_may_need probably isn't used after this, but fix it anyway */ + phinfo->ph_may_need = bms_del_member(phinfo->ph_may_need, relid); } /* |