git.postgresql.org Git - postgresql.git/commit

git projects / postgresql.git / commit

summary | shortlog | log | commit | commitdiff | tree
(parent: 2415ad9) | patch

Fix best_inner_indexscan to return both the cheapest-total-cost and

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.

RSS Atom