From: Jean-Luc Lachance <jllachan@nsd.ca>
To: pgsql-general@postgresql.org
To: pgsql-performance@postgresql.org
Subject: Re: [PERFORM] CLUSTER command
Date: Thu, 12 Dec 2002 16:40:24 -0500
Message-ID: <3DF90248.9BAF931C@nsd.ca> (raw)
References: <5.1.0.14.1.20021212010621.0273d040@mbox.jaring.my>
<5.1.0.14.1.20021212010621.0273d040@mbox.jaring.my>
<5.1.0.14.1.20021213043655.027360b0@mbox.jaring.my>
<3DF90042.E5290B7F@nsd.ca>
Oh, and something else,
I think the syntax should be:
Cluster <table> on <attribute>
Maybe inheritance can be use here.
The problem is creating the new "table" when a new key is detected.
I know, I can use rules, but the optimiser is not aware of the
clustering.
Enough from me for now.
What do you think?
JLL
Jean-Luc Lachance wrote:
>
> Hi all,
>
> I just read about the cluster command and was a little (very)
> disapointed.
> Clustered tables do not remain clustered after inserts.
> Clustered tables are usefull when the table is very large and there are
> few different keys.
>
> Because the table file is already extended (2G limit) using different
> files extension (.N)
> how complicated (modifying the code) would it be to have the table files
> split according to the cluster key?
>
> This would:
>
> Greatly improve performance when the cluster key in included in search
> criteria.
> Allow for a much larger table before a file has to be split (.N).
> Simplify the management of symblinks (that's something else we need to
> look at).
> The index file for that field would no longer be required.
>
> Of course, there should be only one cluster key per table.
> The length the "key" should be short and the number of unique key should
> be low as well.
>
> SO... ?
>
> JLL
>
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To: pgsql-interfaces@postgresql.org
Cc: jllachan@nsd.ca, pgsql-general@postgresql.org, pgsql-performance@postgresql.org
Subject: Re: [PERFORM] CLUSTER command
In-Reply-To: <3DF90248.9BAF931C@nsd.ca>
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