Re: sort_mem param of postgresql.conf

On Wed, 12 Nov 2008, Grzegorz Ja~[kiewicz wrote:

> that's on 8.3, by default there was no sort_mem , I hadded it , changed it
> to 512MB and all of the sudent everything started to fly - wherever it
> required hudge ammounts of memory for queries. The queries are reports, so
> they basicaly join few tables, and dump all ofthat content - so it takes a
> bit of a memory to do it ;)

Be advised that the work_mem setting (and its deprecated alias sort_mem)
are on a per-client basis. So if you have a bunch of people running
reports with that setting, you might discover your server running out of
memory; that's a really high setting. Generally, if it's only a report or
two that need a lot more working memory for sorts, you can do this at the
beginning of them instead:

set work_mem='512MB';

Which will set the value only for that session.

--
* Greg Smith gsmith(at)gregsmith(dot)com http://www.gregsmith.com Baltimore, MD