thread-index: AceBI3wD8EDssVUWSuefCv4WVrOfkw==
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Subject: Re: log_autovacuum
From: "Simon Riggs" <simon@2ndquadrant.com>
To: "Alvaro Herrera" <alvherre@commandprompt.com>
Cc: <pgsql-patches@postgresql.org>
In-Reply-To: <20070417184550.GC15495@alvh.no-ip.org>
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	<1173378696.3641.162.camel@silverbirch.site>
	<20070417180633.GA15495@alvh.no-ip.org>
	<1176834315.3635.414.camel@silverbirch.site>
	<20070417184550.GC15495@alvh.no-ip.org>
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Date: Tue, 17 Apr 2007 20:01:57 +0100
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On Tue, 2007-04-17 at 14:45 -0400, Alvaro Herrera wrote:
> Simon Riggs wrote:
> > On Tue, 2007-04-17 at 14:06 -0400, Alvaro Herrera wrote:
> 
> > > I've tinkered with this patch a bit.  Sample output:
> > > 
> > > LOG:  automatic vacuum of table "alvherre.public.foo": index scans: 0
> > >         pages: removed 0, 11226 remain
> > >         tuples: 1300683 removed, 1096236 remain
> > >         system usage: CPU 0.29s/0.38u sec elapsed 2.56 sec
> > > 
> > > Please comment.
> > 
> > Well, 'tis great except when you have very very frequent autovacuums.
> > That was why I wanted it in 1 log line.
> > 
> > Perhaps we need this as an integer, so we can log all vacuums that last
> > for longer in seconds than the setting, 0 logs all. That would
> > significantly reduce the volume if we set it to 5, say. That way you
> > would get your readability and I would get my reasonable size logs.
> 
> It kinda smells funny to have a setting like that.  Do we have a
> precedent?  If other people is OK with it, I'll do that.

log_temp_files works a bit like that, as does log_min_duration_statement

perhaps log_min_duration_vacuum?
that would be easier to understand

> Would it work to add a separate GUC var to control the minimum autovac
> time?  Also, why do it by time and not by amount of tuples/pages
> removed?

...because you only want to know about slow vacuums.

Time is a more natural unit than tuples removed.

-- 
  Simon Riggs             
  EnterpriseDB   http://www.enterprisedb.com