Richard Jones <rj@xxxxxxxxxxxx> writes: > I'm seeing poor query performance using partitioned tables with check > constraints, seems like the plan is much worse than when querying the > individual partitions manually. > select version(); --> PostgreSQL 9.1.1 on x86_64-unknown-linux-gnu, > compiled by gcc (Debian 4.4.5-8) 4.4.5, 64-bit I get a reasonable-looking plan when I try to duplicate this issue in 9.1 branch tip. I think the reason you're not getting the right behavior is that you are missing this as-yet-unreleased patch: http://git.postgresql.org/gitweb/?p=postgresql.git&a=commitdiff&h=ef03b34550e3577c4be3baa25b70787f5646c57b which means it can't figure out that the available index on the child table produces the desired sort order. If you're in a position to compile from source, a current nightly snapshot of the 9.1 branch ought to work for you; otherwise, wait for 9.1.4. (Note: although that patch is a one-liner, I would *not* recommend trying to just cherry-pick the patch by itself; I think it probably interacts with other planner fixes made since 9.1.1.) regards, tom lane -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
