From: | tgl(at)postgresql(dot)org (Tom Lane) |
---|---|
To: | pgsql-committers(at)postgresql(dot)org |
Subject: | pgsql: Fix choose_bitmap_and() so that partial index predicates are |
Date: | 2006-05-18 19:56:56 |
Message-ID: | 20060518195656.CA7F69FA2EB@postgresql.org |
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Lists: | pgsql-committers |
Log Message:
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Fix choose_bitmap_and() so that partial index predicates are considered when
deciding whether a potential additional indexscan is redundant or not. As now
coded, any use of a partial index that was already used in a previous AND arm
will be rejected as redundant. This might be overly restrictive, but not
considering the point at all is definitely bad, as per example in bug #2441
from Arjen van der Meijden. In particular, a clauseless scan of a partial
index was *never* considered redundant by the previous coding, and that's
surely wrong. Being more flexible would also require some consideration
of how not to double-count the index predicate's selectivity.
Tags:
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REL8_1_STABLE
Modified Files:
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pgsql/src/backend/optimizer/path:
indxpath.c (r1.191.2.7 -> r1.191.2.8)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/optimizer/path/indxpath.c.diff?r1=1.191.2.7&r2=1.191.2.8)
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