Re: No hash join across partitioned tables?
Tom Lane <tgl@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>
To: Kris Jurka <books@ejurka.com>
Cc: pgsql-performance@postgresql.org
Date: 2009-04-17T15:02:34Z
Lists: pgsql-hackers, pgsql-performance
Kris Jurka <books@ejurka.com> writes: > So the default disable_cost isn't enough to push it to use the hash join > plan and goes back to nestloop. Since disable_cost hasn't been touched > since January 2000, perhaps it's time to bump that up to match today's > hardware and problem sizes? I think disable_cost was originally set at a time when costs were integers :-(. Yeah, there's probably no reason not to throw another zero or two on it. Is there another issue here besides that one? I think you were hoping that the hash join would be faster than the alternatives, but the cost estimate says it's a lot slower. Is that actually the case? regards, tom lane