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Re: Equivalent praxis to CLUSTERED INDEX?

From: "Gregory S(dot) Williamson" <gsw(at)globexplorer(dot)com>
To: "Gaetano Mendola" <mendola(at)bigfoot(dot)com>,"Bruce Momjian" <pgman(at)candle(dot)pha(dot)pa(dot)us>,<pgsql-performance(at)postgresql(dot)org>
Subject: Re: Equivalent praxis to CLUSTERED INDEX?
Date: 2004-08-26 22:36:21
Message-ID: 71E37EF6B7DCC1499CEA0316A256832801D4B6FA@loki.wc.globexplorer.net (view raw or flat)
Thread:
Lists: pgsql-performance
FWIW,

Informix does allow the fragmentation of data over named dbspaces by round-robin and expression; this is autosupporting as long as the dba keeps enough space available. You may also fragment the index although there are some variations depending on type of Informix (XPS, etc.); this is available in at least 9.3 ... I have never used the index fragmentation as its own beast, but the fragmenting of data works like a charm for spreadling load over more disks.

Greg Williamson
DBA
GlobeXplorer LLC

-----Original Message-----
From: Gaetano Mendola [mailto:mendola(at)bigfoot(dot)com]
Sent: Thursday, August 26, 2004 2:10 PM
To: Bruce Momjian; pgsql-performance(at)postgresql(dot)org
Subject: Re: [PERFORM] Equivalent praxis to CLUSTERED INDEX?


Bruce Momjian wrote:
> How do vendors actually implement auto-clustering?  I assume they move
> rows around during quiet periods or have lots of empty space in each
> value bucket.
> 
> ---------------------------------------------------------------------------

IIRC informix doesn't have it, and you have to recluster periodically
the table. After having clustered the table with an index in order to
recluster the table with another index you have to release the previous
one ( ALTER index TO NOT CLUSTER ), the CLUSTER is an index attribute and
each table can have only one index with that attribute ON.


Regards
Gaetano Mendola



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Subject: Re: Equivalent praxis to CLUSTERED INDEX?
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