On Wed, Nov 5, 2008 at 8:09 AM, Grzegorz Jaśkiewicz <gryzman@gmail.com> wrote:
> hey folks,
>
> so suppose I have a query that in explain analyze
>
> Sort Method: external merge Disk: 218080kB
>
> What param should I set to high up, to end up with that sort in memory, and
work_mem
> also - will that memory will always be allocated per connection,
It is allocated PER SORT, up to the amount needed. Note that you can
set work_mem for a given connection to override the default setting,
so you don't have to set workmem to 256M for everybody, but just this
one operation. You can also set default work_mem per user and per
database.
> (I am bit
> worried that having say 320MB of temporary memory space per connection will
> reduce number of possible connections). The query is not run quite often,
> but it would be nice to see it running faster, as it is a report type of
> query - and these ppl are usualy very unpatient. Currently it runs around
> 1-2 minutes with 1-6M rows to process join etc across 2-3 tables.
Definitely look at setting it in this connection at run time then.