From: Tom Lane <tgl@sss.pgh.pa.us>
To: David logan <djlogan2@comcast.net>
Cc: pgsql-performance@postgresql.org
Subject: Re: Mystefied at poor performance of a standard query
Date: Wed, 01 Oct 2008 09:30:12 -0400
Message-ID: <8396.1222867812@sss.pgh.pa.us> (raw)
In-Reply-To: <004001c923be$d8b1f730$8a15e590$@net>
References: <004001c923be$d8b1f730$8a15e590$@net>
"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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To: pgsql-performance@postgresql.org
Cc: tgl@sss.pgh.pa.us, djlogan2@comcast.net
Subject: Re: Mystefied at poor performance of a standard query
In-Reply-To: <8396.1222867812@sss.pgh.pa.us>
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