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Re: Mystefied at poor performance of a standard query - Mailing list pgsql-performance

From Tom Lane
Subject Re: Mystefied at poor performance of a standard query
Date
Msg-id 8396.1222867812@sss.pgh.pa.us
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In response to Mystefied at poor performance of a standard query  ("David logan" <djlogan2@comcast.net>)
Responses Re: Mystefied at poor performance of a standard query  ("David logan" <djlogan2@comcast.net>)
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"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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