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author | Tom Lane | 2006-05-18 19:56:56 +0000 |
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committer | Tom Lane | 2006-05-18 19:56:56 +0000 |
commit | 1c01a5108a4f37bfa34e42629a8bf8b7a7191192 (patch) | |
tree | bb17d51824f137631f52c1a54b9f2db10478de3b /doc/FAQ_DEV | |
parent | 59ca5ebf2cc1f4e8aade34b693e99c9185d74218 (diff) |
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.
Diffstat (limited to 'doc/FAQ_DEV')
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