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Re: in-memory sorting

From: Samuel Gendler <sgendler(at)ideasculptor(dot)com>
To: Scott Marlowe <scott(dot)marlowe(at)gmail(dot)com>
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: in-memory sorting
Date: 2010-08-19 06:38:50
Message-ID: AANLkTinhNT_QujPGhFoqUX9ts2hW-4whvMOWNBXhwU0=@mail.gmail.com (view raw or flat)
Thread:
Lists: pgsql-performance
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(dot)marlowe(at)gmail(dot)com>wrote:

> On Wed, Aug 18, 2010 at 11:45 PM, Samuel Gendler
> <sgendler(at)ideasculptor(dot)com> 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';
>

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Subject: Re: yet another q
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Subject: Re: in-memory sorting

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