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author | Tom Lane <tgl@sss.pgh.pa.us> | 2007-05-22 01:40:33 +0000 |
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committer | Tom Lane <tgl@sss.pgh.pa.us> | 2007-05-22 01:40:33 +0000 |
commit | d7153c5fadca610248775ef9c22ede85f08fd26a (patch) | |
tree | 989a2483def7d8b8805353a8341a4607c54aec29 /src/backend/executor/nodeBitmapIndexscan.c | |
parent | 2415ad983174164ff30ce487c0e6b4b53321b83a (diff) | |
download | postgresql-d7153c5fadca610248775ef9c22ede85f08fd26a.tar.gz postgresql-d7153c5fadca610248775ef9c22ede85f08fd26a.zip |
Fix best_inner_indexscan to return both the cheapest-total-cost and
cheapest-startup-cost innerjoin indexscans, and make joinpath.c consider
both of these (when different) as the inside of a nestloop join. The
original design was based on the assumption that indexscan paths always
have negligible startup cost, and so total cost is the only important
figure of merit; an assumption that's obviously broken by bitmap
indexscans. This oversight could lead to choosing poor plans in cases
where fast-start behavior is more important than total cost, such as
LIMIT and IN queries. 8.1-vintage brain fade exposed by an example from
Chuck D.
Diffstat (limited to 'src/backend/executor/nodeBitmapIndexscan.c')
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