From: Michael Stone <mstone+postgres@mathom.us>
To: pgsql-performance@postgresql.org
Subject: Re: [doc patch] a slight VACUUM / VACUUM FULL doc improvement proposal
Date: Wed, 16 May 2007 17:17:16 -0400
Message-ID: <20070516211713.GJ1785@mathom.us> (raw)
In-Reply-To: <608xbotve5.fsf@dba2.int.libertyrms.com>
References: <87lkfqavg9.fsf@meuh.mnc.lan>
<20070515174427.GG1785@mathom.us>
<87hcqdb4g5.fsf@meuh.mnc.lan>
<20070516154809.GL14548@nasby.net>
<877ir892ss.fsf@meuh.mnc.lan>
<20070516160926.GX4582@alvh.no-ip.org>
<20070516162035.GI1785@mathom.us>
<608xbotve5.fsf@dba2.int.libertyrms.com>
On Wed, May 16, 2007 at 03:34:42PM -0400, Chris Browne wrote:
>mstone+postgres@mathom.us (Michael Stone) writes:
>> Unless, of course, you don't particularly care about the order of
>> the items in your table; you might end up wasting vastly more time
>> rewriting tables due to unnecessary clustering than for full vacuums
>> on a table that doesn't need it.
>
>Actually, this is irrelevant.
I think it's perfectly relevant.
>If CLUSTER is faster than VACUUM FULL (and if it isn't, in all cases,
>it *frequently* is, and probably will be, nearly always, soon), then
>it's a faster workaround.
Cluster reorders the table. If a table doesn't have any dead rows and
you tell someone to run cluster or vacuum full, the vaccuum basically
won't do anything and the cluster will reorder the whole table. Cluster
is great for certain access patterns, but I've been noticing this odd
tendency lately to treat it like a silver bullet.
Mike Stone
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To: pgsql-performance@postgresql.org
Cc: mstone+postgres@mathom.us
Subject: Re: [doc patch] a slight VACUUM / VACUUM FULL doc improvement proposal
In-Reply-To: <20070516211713.GJ1785@mathom.us>
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