Re: Mystefied at poor performance of a standard query

Looks like that worked. I set work_mem to 256MB, and it looks like my
standard sql came back in just a couple of seconds.

Thanks!

-----Original Message-----
From: pgsql-performance-owner@postgresql.org
[mailto:pgsql-performance-owner@postgresql.org] On Behalf Of Tom Lane
Sent: Wednesday, October 01, 2008 07:30
To: David logan
Cc: pgsql-performance@postgresql.org
Subject: Re: [PERFORM] Mystefied at poor performance of a standard query

"David logan" <djlogan2@comcast.net> writes:
> (The question is why this simple select takes me 20 minutes to run...)

What have you got work_mem set to?  The hash join is not going to be
real fast if it has to split the join into multiple batches, so you
want work_mem large enough to hold the whole inner relation.  That would
be at least 20MB in this example, probably quite a bit more after
allowing for per-row overhead in the table.

            regards, tom lane

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