diff options
| author | Tom Lane | 2010-09-28 16:08:56 +0000 |
|---|---|---|
| committer | Tom Lane | 2010-09-28 18:19:00 +0000 |
| commit | eb229505103eb5494c33832d422584bfdee03fc6 (patch) | |
| tree | ca7c12732d170cb5abef8f108b2d95f508444b7c /src/include/optimizer | |
| parent | 9c5f4f6cb50dd22028acc0b6f20291a5edcac62b (diff) | |
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/include/optimizer')
| -rw-r--r-- | src/include/optimizer/placeholder.h | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/src/include/optimizer/placeholder.h b/src/include/optimizer/placeholder.h index 3f921a983a4..22d52411c2a 100644 --- a/src/include/optimizer/placeholder.h +++ b/src/include/optimizer/placeholder.h @@ -21,7 +21,10 @@ extern PlaceHolderVar *make_placeholder_expr(PlannerInfo *root, Expr *expr, Relids phrels); extern PlaceHolderInfo *find_placeholder_info(PlannerInfo *root, PlaceHolderVar *phv); -extern void fix_placeholder_eval_levels(PlannerInfo *root); +extern void find_placeholders_in_jointree(PlannerInfo *root); +extern void update_placeholder_eval_levels(PlannerInfo *root, + SpecialJoinInfo *new_sjinfo); +extern void fix_placeholder_input_needed_levels(PlannerInfo *root); extern void add_placeholders_to_base_rels(PlannerInfo *root); extern void add_placeholders_to_joinrel(PlannerInfo *root, RelOptInfo *joinrel); |