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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: 200408271748.i7RHmfJ15766@candle.pha.pa.us (view raw or flat)
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                        |  http://candle.pha.pa.us
  pgman(at)candle(dot)pha(dot)pa(dot)us               |  (610) 359-1001
  +  If your life is a hard drive,     |  13 Roberts Road
  +  Christ can be your backup.        |  Newtown Square, Pennsylvania 19073

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Next:From: Tom LaneDate: 2004-08-27 18:19:29
Subject: Re: Equivalent praxis to CLUSTERED INDEX?
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