From: Chris Browne <cbbrowne@acm.org>
To: pgsql-performance@postgresql.org
Subject: Re: Clustered tables improves perfs ?
Date: Thu, 13 Sep 2007 10:49:57 -0400
Message-ID: <608x7azkkq.fsf@dba2.int.libertyrms.com> (raw)
References: <46E9353A.9080602@agematis.com>
pcastet@agematis.com (Patrice Castet) writes:
> I wonder if clustering a table improves perfs somehow ?
> Any example/ideas about that ?
> ref : http://www.postgresql.org/docs/8.2/interactive/sql-cluster.html
Sometimes.
1. It compacts the table, which may be of value, particularly if the
table is not seeing heavy UPDATE/DELETE traffic. VACUUM and VACUUM
FULL do somewhat similar things; if you are using VACUUM frequently
enough, this is not likely to have a material effect.
2. It transforms the contents of the table into some specified order,
which will improve efficiency for any queries that use that specific
ordering.
--
output = reverse("moc.enworbbc" "@" "enworbbc")
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To: pgsql-performance@postgresql.org
Cc: cbbrowne@acm.org
Subject: Re: Clustered tables improves perfs ?
In-Reply-To: <608x7azkkq.fsf@dba2.int.libertyrms.com>
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