Re: 2GB or not 2GB

From: Simon Riggs <simon(at)2ndquadrant(dot)com>
To: josh(at)agliodbs(dot)com
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: 2GB or not 2GB
Date: 2008-05-31 07:44:57
Message-ID: 1212219897.4120.195.camel@ebony.site
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On Wed, 2008-05-28 at 16:59 -0700, Josh Berkus wrote:

> sort_mem: My tests with 8.2 and DBT3 seemed to show that, due to
> limitations of our tape sort algorithm, allocating over 2GB for a single
> sort had no benefit. However, Magnus and others have claimed otherwise.
> Has this improved in 8.3?

There is an optimum for each specific sort.

Your results cannot be used to make a global recommendation about the
setting of work_mem. So not finding any benefit in your tests *and*
Magnus seeing an improvement are not inconsistent events.

--
Simon Riggs www.2ndQuadrant.com
PostgreSQL Training, Services and Support

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