From: | "David logan" <djlogan2(at)comcast(dot)net> |
---|---|
To: | "'Tom Lane'" <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
Cc: | <pgsql-performance(at)postgresql(dot)org> |
Subject: | Re: Mystefied at poor performance of a standard query |
Date: | 2008-10-01 16:38:21 |
Message-ID: | 006b01c923e4$25da50f0$718ef2d0$@net |
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Thread: | |
Lists: | pgsql-performance |
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(at)postgresql(dot)org
[mailto:pgsql-performance-owner(at)postgresql(dot)org] On Behalf Of Tom Lane
Sent: Wednesday, October 01, 2008 07:30
To: David logan
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: [PERFORM] Mystefied at poor performance of a standard query
"David logan" <djlogan2(at)comcast(dot)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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