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Re: Re: Increasing work_mem and shared_buffers on Postgres 9.2 significantly slows down queries

From: Jeff Janes <jeff(dot)janes(at)gmail(dot)com>
To: Gunnar Nick Bluth <gunnar(dot)bluth(at)pro-open(dot)de>
Cc: Petr Praus <petr(at)praus(dot)net>, Marcos Ortiz <mlortiz(at)uci(dot)cu>, pgsql-performance(at)postgresql(dot)org
Subject: Re: Re: Increasing work_mem and shared_buffers on Postgres 9.2 significantly slows down queries
Date: 2012-11-05 16:44:34
Message-ID: CAMkU=1wkUvrJGSj7kJq3CqoSBmKr7qtAMsqEPEBCnggwv4Yn2A@mail.gmail.com (view raw or flat)
Thread:
Lists: pgsql-performance
On Sat, Nov 3, 2012 at 10:09 AM, Gunnar "Nick" Bluth
<gunnar(dot)bluth(at)pro-open(dot)de> wrote:

> Well, I'm pretty sure that having more work_mem is a good thing (tm)
> normally ;-)

In my experience when doing sorts in isolation, having more work_mem
is a bad thing, unless it enables you to remove a layer of
tape-merging.  I always blamed it on the L1/L2 etc. levels of caching.

Cheers,

Jeff


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