From: Tobias Brox <tobias@nordicbet.com>
To: Daryl Herzmann <akrherz@iastate.edu>
Cc: pgsql-performance@postgresql.org
Subject: Re: Missing the point of autovacuum
Date: Sat, 6 Jan 2007 20:33:13 +0100
Message-ID: <20070106193313.GB30486@oppetid.no> (raw)
In-Reply-To: <Pine.LNX.4.61.0701061247440.5569@ics128-198.icsincorporated.com>
References: <Pine.LNX.4.61.0701061247440.5569@ics128-198.icsincorporated.com>
[Daryl Herzmann - Sat at 12:59:03PM -0600]
> As the months have gone by, I notice many of my tables having *lots* of
> unused item pointers. For example,
Probably not the issue here, but we had some similar issue where we had
many long-running transactions - i.e. some careless colleague entering
"begin" into his psql shell and leaving it running for some days without
entering "commit" or "rollback", plus some instances where the
applications started a transaction without closing it.
> Perhaps I shouldn't be concerned with this? In all, I've got around 400
> GB of data on postgresql, but am not sure how much of it is old data.
I didn't count the zeroes, but autovacuum does have rules saying it will
not touch the table until some percentages of it needs to be vacuumed
off. This is of course configurable.
> Do I need to be running old fashioned 'vacuumdb' routinely as well? I
> guess I just don't understand why autovacuum is not automatically doing
> this for me and I have tables with so many unused item pointers.
If you have some period of the day with less activity than else, it is a
good idea running an old-fashionated vacuum as well. The regular vacuum
process will benefit from any work done by the autovacuum.
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To: pgsql-performance@postgresql.org
Cc: tobias@nordicbet.com, akrherz@iastate.edu
Subject: Re: Missing the point of autovacuum
In-Reply-To: <20070106193313.GB30486@oppetid.no>
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