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Message-ID: <dcc563d10810311131h68980c73gdfc6ada9bdfda12@mail.gmail.com>
Date: Fri, 31 Oct 2008 12:31:56 -0600
From: "Scott Marlowe" <scott.marlowe@gmail.com>
To: "Alvaro Herrera" <alvherre@commandprompt.com>
Subject: Re: autovacuum questions
Cc: "Rafael Domiciano" <rafael.domiciano@gmail.com>,
	isabella.ghiurea@nrc-cnrc.gc.ca, pgsql-admin@postgresql.org
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References: <490B2161.1070502@nrc-cnrc.gc.ca>
	<3a0028490810310832t2972fb95l6c8d01e7895c1b6c@mail.gmail.com>
	<20081031160213.GC10668@alvh.no-ip.org>

On Fri, Oct 31, 2008 at 10:02 AM, Alvaro Herrera
<alvherre@commandprompt.com> wrote:
> Rafael Domiciano escribi=F3:
>
>> The vacuum is not full, to run a full vacuum you need to set a cron job;
>> better to run at the night.
>
> Doing VACUUM FULL on crontab is rarely a good idea.  If you find
> yourself in a situation where you need VACUUM FULL, then you've not
> tuned regular vacuum appropriately.

There are some use cases where vacuum full is appropriate.  But
they're rare.  And they're usually better off being added to whatever
script is doing the thing that causes the database to need vacuum
full.  Certain batch processing or data loading processes need vacuum
full and or reindex when finishing.

But the common thought process on vacuum full for most people is "If
vacuum is good, vacuum full must be even better!" which is just wrong.