From: Greg Smith <gsmith@gregsmith.com>
To: pgsql-performance@postgresql.org
Subject: Re: PostgreSQL Configuration Tool for Dummies
Date: Tue, 26 Jun 2007 14:14:24 -0400 (EDT)
Message-ID: <Pine.GSO.4.64.0706261401240.6715@westnet.com> (raw)
In-Reply-To: <200706260826.28935.josh@agliodbs.com>
References: <A3AC4FA47DC0B1458C3E5396E685E63302395E63@SAB-DC1.sab.uiuc.edu>
<200706191254.09777.josh@agliodbs.com>
<Pine.GSO.4.64.0706200155290.16657@westnet.com>
<200706260826.28935.josh@agliodbs.com>
On Tue, 26 Jun 2007, Josh Berkus wrote:
> The problem is that there are no "safe, middle-of-the-road" values for some
> things, particularly max_connections and work_mem.
Your max_connections concern is one fact that haunts the idea of just
giving out some sample configs for people. Lance's tool asks outright the
expectation for max_connections which I think is the right thing to do.
> Web app, typical machine:
> work_mem = 256kb
> default_statistics_target=100
> autovacuum=on
> Reporting app, same machine:
> work_mem = 32mb
> default_statistics_target=500
> autovacuum=off
I think people are stuck with actually learning a bit about work_mem
whether they like it or not, because it's important to make it larger but
we know going too high will be a problem with lots of connections doing
sorts.
As for turning autovacuum on/off and the stats target, I'd expect useful
defaults for those would come out of how the current sample is asking
about read vs. write workloads and expected database size. Those simple
to understand questions might capture enough of the difference between
your two types here.
--
* Greg Smith gsmith@gregsmith.com http://www.gregsmith.com Baltimore, MD
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To: pgsql-performance@postgresql.org
Cc: gsmith@gregsmith.com
Subject: Re: PostgreSQL Configuration Tool for Dummies
In-Reply-To: <Pine.GSO.4.64.0706261401240.6715@westnet.com>
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