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author | Tom Lane <tgl@sss.pgh.pa.us> | 2011-09-24 19:33:16 -0400 |
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committer | Tom Lane <tgl@sss.pgh.pa.us> | 2011-09-24 19:33:16 -0400 |
commit | 7741dd6590073719688891898e85f0cb73453159 (patch) | |
tree | 98b57a56460a9b9313609e598efe1b7cf11a6f13 /src/backend/access/gist/gistget.c | |
parent | 337c0b03614c45516f2c3ec956405713bb264d54 (diff) | |
download | postgresql-7741dd6590073719688891898e85f0cb73453159.tar.gz postgresql-7741dd6590073719688891898e85f0cb73453159.zip |
Recognize self-contradictory restriction clauses for non-table relations.
The constraint exclusion feature checks for contradictions among scan
restriction clauses, as well as contradictions between those clauses and a
table's CHECK constraints. The first aspect of this testing can be useful
for non-table relations (such as subqueries or functions-in-FROM), but the
feature was coded with only the CHECK case in mind so we were applying it
only to plain-table RTEs. Move the relation_excluded_by_constraints call
so that it is applied to all RTEs not just plain tables. With the default
setting of constraint_exclusion this results in no extra work, but with
constraint_exclusion = ON we will detect optimizations that we missed
before (at the cost of more planner cycles than we expended before).
Per a gripe from Gunnlaugur Þór Briem. Experimentation with
his example also showed we were not being very bright about the case where
constraint exclusion is proven within a subquery within UNION ALL, so tweak
the code to allow set_append_rel_pathlist to recognize such cases.
Diffstat (limited to 'src/backend/access/gist/gistget.c')
0 files changed, 0 insertions, 0 deletions