From: | "Matthew Nuzum" <matt(dot)followers(at)gmail(dot)com> |
---|---|
To: | "'Tom Lane'" <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
Cc: | <pgsql-performance(at)postgresql(dot)org> |
Subject: | Re: Preventing query from hogging server |
Date: | 2005-03-24 20:13:01 |
Message-ID: | 42431f52.4700af57.2963.ffffe2b8@mx.gmail.com |
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Thread: | |
Lists: | pgsql-performance |
> I would strongly suggest doing the min and max calculations together:
>
> select groupid, min(col), max(col) from ...
>
> because if you do them in two separate queries 90% of the effort will be
> duplicated.
>
> regards, tom lane
Thanks. Other than avoiding using too much sort mem, is there anything else
I can do to ensure this query doesn't starve other processes for resources?
Doing the explain analyze only increases my server load by 1 and seems to
readily relinquish CPU time, but previously when I had been running a test
query my server load rose to unacceptable levels.
FWIW, the explain was run from psql running on the db server, the test query
the other day was run from one of the webservers. Should I run this on the
db server to minimize load?
--
Matthew Nuzum <matt(at)followers(dot)net>
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