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| author | Tom Lane <tgl@sss.pgh.pa.us> | 2005-03-01 01:40:39 +0000 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2005-03-01 01:40:39 +0000 |
| commit | bfc294232192d32de22815ffced86fa17bc4d22f (patch) | |
| tree | 244869ceaacc7a117d8058e1e0ba074b0e7470f1 /src/backend/optimizer/path/orindxpath.c | |
| parent | 3da9fd85449d0fd353d81818671c82eac115e59a (diff) | |
| download | postgresql-bfc294232192d32de22815ffced86fa17bc4d22f.tar.gz postgresql-bfc294232192d32de22815ffced86fa17bc4d22f.zip | |
Adjust OR indexscan logic to not generate redundant condition-free OR
indexscans involving partial indexes. These would always be dominated
by a simple indexscan on such an index, so there's no point in considering
them. Fixes overoptimism in a patch I applied last October.
Diffstat (limited to 'src/backend/optimizer/path/orindxpath.c')
| -rw-r--r-- | src/backend/optimizer/path/orindxpath.c | 12 |
1 files changed, 8 insertions, 4 deletions
diff --git a/src/backend/optimizer/path/orindxpath.c b/src/backend/optimizer/path/orindxpath.c index 210abfe1d9e..0afc8143fd8 100644 --- a/src/backend/optimizer/path/orindxpath.c +++ b/src/backend/optimizer/path/orindxpath.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/optimizer/path/orindxpath.c,v 1.64 2004/12/31 22:00:04 pgsql Exp $ + * $PostgreSQL: pgsql/src/backend/optimizer/path/orindxpath.c,v 1.64.4.1 2005/03/01 01:40:39 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -387,10 +387,14 @@ best_or_subclause_index(Query *root, /* * Ignore index if it doesn't match the subclause at all; except - * that if it's a partial index, consider it anyway, since the - * selectivity of the predicate alone might make the index useful. + * that if it's a partial index matching the current OR subclause, + * consider it anyway, since effectively we are using the index + * predicate to match the subclause. (Note: we exclude partial + * indexes that are predOK; else such a partial index would be + * considered to match *every* OR subclause, generating bogus OR + * plans that are redundant with the basic scan on that index.) */ - if (indexclauses == NIL && index->indpred == NIL) + if (indexclauses == NIL && (index->indpred == NIL || index->predOK)) continue; /* Convert clauses to indexquals the executor can handle */ |