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Re: Equivalent praxis to CLUSTERED INDEX?

From: Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>
To: Adi Alurkar <adi(at)sf(dot)net>
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: Equivalent praxis to CLUSTERED INDEX?
Date: 2004-08-27 17:48:41
Message-ID: (view raw or whole thread)
Lists: pgsql-performance
Adi Alurkar wrote:
> IIRC it it to reduce the "overflow" of data or what oracle calls  
> chained rows. i.e if a table has variable length columns and 10 rows  
> get inserted into a datapage, if this datapage is full and one of the  
> variable length field gets updated the row will now "overflow" into  
> another datapage, but if the datapage is created with an appropriate  
> amount of free space the updated row will be stored in one single  
> datapage.

Agreed.  What I am wondering is with our system where every update gets
a new row, how would this help us?  I know we try to keep an update on
the same row as the original, but is there any significant performance
benefit to doing that which would offset the compaction advantage?

  Bruce Momjian                        |
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  +  If your life is a hard drive,     |  13 Roberts Road
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