Message-ID: <46F6BA82.3080101@mochima.com>
Date: Sun, 23 Sep 2007 15:12:02 -0400
From: Carlos Moreno <moreno_pg@mochima.com>
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To: pgsql-performance@postgresql.org
Subject: Re: Possible explanations for catastrophic performace	deterioration?
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	<20070923182349.GC5679@alvh.no-ip.org>
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>> I don't understand this argument --- the newer system has actually
>> less memory than the old one;  how could it fit there and not on the
>> old one?  Plus, how could dropping-recreating the database on the same
>> machine change the fact that the entire dataset entirely fit or not in
>> memory??
>
> Because on the older server it is bloated, while on the new one it is
> fresh thus no dead tuples.

Wait a second --- am I correct in understanding then that the bloating
you guys are referring to occurs *in memory*??

My mind has been operating under the assumption that bloating only
occurs on disk, and never in memory --- is there where my logic is
mistaken?

>> I wonder if I should then periodically run a vacuum full --- say, once
>> a week?  Once a month?
>
> Never.  What you need to do is make sure your FSM settings
> (fsm_max_pages in particular) are high enough, and that you VACUUM (not
> full) frequently enough.

Noted.

Thanks!

Carlos
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