Re: in-memory sorting

[Samuel Gendler <sgendler@xxxxxxxxxxxxxxxx>]

Yeah, although with 48GB of available memory and not that much concurrency, I'm not sure it matters that much. But point taken, I'll see about modifying the app such that work_mem gets set on a per-query basis.

On Wed, Aug 18, 2010 at 11:24 PM, Scott Marlowe <scott.marlowe@xxxxxxxxx> wrote:

On Wed, Aug 18, 2010 at 11:45 PM, Samuel Gendler
<sgendler@xxxxxxxxxxxxxxxx> wrote:
> Answered my own question.  Cranking work_mem up to 350MB revealed that
> the in-memory sort requires more memory than the disk sort.

Note that unless you run VERY few client connections, it's usually
better to leave work_mem somewhere in the 1 to 32Meg range and have
the connection or user or database that needs 350Meg be set there.

I.e.

<connect>
set work_mem='512MB';
<execute query

OR

alter user memoryhog set work_mem='512MB';

OR

alter database memhogdb set work_mem='512MB';