Re: Simple postgresql.conf wizard

From: "Joshua D(dot) Drake" <jd(at)commandprompt(dot)com>
To: Robert Haas <robertmhaas(at)gmail(dot)com>
Cc: Greg Smith <gsmith(at)gregsmith(dot)com>, Josh Berkus <josh(at)agliodbs(dot)com>, pgsql-hackers(at)postgresql(dot)org
Subject: Re: Simple postgresql.conf wizard
Date: 2008-12-03 21:11:11
Message-ID: 1228338671.27483.160.camel@jd-laptop.pragmaticzealot.org
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On Wed, 2008-12-03 at 15:21 -0500, Robert Haas wrote:
> >> I'm not sure what "mixed" mode is supposed to be, but based on what
> >> I've seen so far, I'm a skeptical of the idea that encouraging people
> >> to raise default_statistics_target to 50 and turn on
> >> constraint_exclusion is reasonable.
> >
> > Why?
>
> Because both of those settings are strictly worse for my database than

I can see an argument about constraint_exclusion but
default_statistics_target I don't.

> the defaults. I don't have any partitioned tables, and see:
>
> http://archives.postgresql.org/pgsql-hackers/2008-11/msg01837.php
> >
> > What does checkpoint_segments have to do with the size of the database?
>
> It seems unlikely that you would want 256 MB of checkpoint segments on
> a database that is only 100 MB (or even 500 MB). But you might very
> well want that on a database that is 1 TB.

It also seems unlikely that you would hit 256MB of checkpoint segments
on a 100MB database before checkpoint_timeout and if you did, you
certainly did need them.

Remember postgresql only creates the segments when it needs them.

Sincerely,

Joshua D. Drake

>
> ...Robert
>
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