diff options
| author | Tom Lane <tgl@sss.pgh.pa.us> | 2008-03-24 21:53:04 +0000 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2008-03-24 21:53:04 +0000 |
| commit | fd791e7b5a1bf53131ad15e68e4d4f8ca795fcb4 (patch) | |
| tree | 4fbde4ad7311749be170edf100dac55fa464c7f3 /src/backend/optimizer/path/joinpath.c | |
| parent | 2a346725bafbc6c7a5dd1771c6004703545a935c (diff) | |
When a relation has been proven empty by constraint exclusion, propagate that
knowledge up through any joins it participates in. We were doing that already
in some special cases but not in the general case. Also, defend against zero
row estimates for the input relations in cost_mergejoin --- this fix may have
eliminated the only scenario in which that can happen, but be safe. Per
report from Alex Solovey.
Diffstat (limited to 'src/backend/optimizer/path/joinpath.c')
| -rw-r--r-- | src/backend/optimizer/path/joinpath.c | 8 |
1 files changed, 3 insertions, 5 deletions
diff --git a/src/backend/optimizer/path/joinpath.c b/src/backend/optimizer/path/joinpath.c index d5e2506d7a0..3e646d10325 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 1.115 2008/01/09 20:42:27 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/optimizer/path/joinpath.c,v 1.116 2008/03/24 21:53:03 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -837,11 +837,9 @@ best_appendrel_indexscan(PlannerInfo *root, RelOptInfo *rel, /* * Check to see if child was rejected by constraint exclusion. If so, - * it will have a cheapest_total_path that's an Append path with no - * members (see set_plain_rel_pathlist). + * it will have a cheapest_total_path that's a "dummy" path. */ - if (IsA(childrel->cheapest_total_path, AppendPath) && - ((AppendPath *) childrel->cheapest_total_path)->subpaths == NIL) + if (IS_DUMMY_PATH(childrel->cheapest_total_path)) continue; /* OK, we can ignore it */ /* |