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author | Tom Lane <tgl@sss.pgh.pa.us> | 2008-09-12 14:56:13 +0000 |
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committer | Tom Lane <tgl@sss.pgh.pa.us> | 2008-09-12 14:56:13 +0000 |
commit | bf0b6ac43c5d5eb7458e0aa4bf5f45c566f7c7d1 (patch) | |
tree | afd42cfd131dc94d557a3b05501aa99b6baa60f3 /src | |
parent | cdd08959788a38965bdef9501e04f1fac2f71f4c (diff) | |
download | postgresql-bf0b6ac43c5d5eb7458e0aa4bf5f45c566f7c7d1.tar.gz postgresql-bf0b6ac43c5d5eb7458e0aa4bf5f45c566f7c7d1.zip |
Skip opfamily check in eclass_matches_any_index() when the index isn't a
btree. We can't easily tell whether clauses generated from the equivalence
class could be used with such an index, so just assume that they might be.
This bit of over-optimization prevented use of non-btree indexes for nestloop
inner indexscans, in any case where the join uses an equality operator that
is also a btree operator --- which in particular is typically true for hash
indexes. Noted while trying to test the current hash index patch.
Diffstat (limited to 'src')
-rw-r--r-- | src/backend/optimizer/path/indxpath.c | 15 |
1 files changed, 13 insertions, 2 deletions
diff --git a/src/backend/optimizer/path/indxpath.c b/src/backend/optimizer/path/indxpath.c index 92a3fb59d1b..297c50389fb 100644 --- a/src/backend/optimizer/path/indxpath.c +++ b/src/backend/optimizer/path/indxpath.c @@ -9,7 +9,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/optimizer/path/indxpath.c,v 1.232 2008/08/14 18:47:59 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/optimizer/path/indxpath.c,v 1.233 2008/09/12 14:56:13 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -1584,7 +1584,18 @@ eclass_matches_any_index(EquivalenceClass *ec, EquivalenceMember *em, { Oid curFamily = families[0]; - if (list_member_oid(ec->ec_opfamilies, curFamily) && + /* + * If it's a btree index, we can reject it if its opfamily isn't + * compatible with the EC, since no clause generated from the + * EC could be used with the index. For non-btree indexes, + * we can't easily tell whether clauses generated from the EC + * could be used with the index, so only check for expression + * match. This might mean we return "true" for a useless index, + * but that will just cause some wasted planner cycles; it's + * better than ignoring useful indexes. + */ + if ((index->relam != BTREE_AM_OID || + list_member_oid(ec->ec_opfamilies, curFamily)) && match_index_to_operand((Node *) em->em_expr, indexcol, index)) return true; |