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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 14:18:22 -0400 |
| commit | 4ec15077b2eaa1f7713e4fff87e220a23c772688 (patch) | |
| tree | 68a194b48c7cb17407f74350fd92073ededbb3ce /src/backend/nodes/copyfuncs.c | |
| parent | cd1454cdc357593f1d17fd33b9583511a9fe57b1 (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/backend/nodes/copyfuncs.c')
| -rw-r--r-- | src/backend/nodes/copyfuncs.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/src/backend/nodes/copyfuncs.c b/src/backend/nodes/copyfuncs.c index 3e237c11d9b..6e6844badea 100644 --- a/src/backend/nodes/copyfuncs.c +++ b/src/backend/nodes/copyfuncs.c @@ -1787,6 +1787,7 @@ _copyPlaceHolderInfo(PlaceHolderInfo *from) COPY_NODE_FIELD(ph_var); COPY_BITMAPSET_FIELD(ph_eval_at); COPY_BITMAPSET_FIELD(ph_needed); + COPY_BITMAPSET_FIELD(ph_may_need); COPY_SCALAR_FIELD(ph_width); return newnode; |