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Re: Index bloat problem?

From: "Jim C(dot) Nasby" <decibel(at)decibel(dot)org>
To: Dave Chapeskie <pgsql(at)ddm(dot)wox(dot)org>,pgsql-perform <pgsql-performance(at)postgresql(dot)org>
Subject: Re: Index bloat problem?
Date: 2005-04-23 03:12:38
Message-ID: 20050423031238.GA58835@decibel.org (view raw or flat)
Thread:
Lists: pgsql-performance
You would be interested in
http://archives.postgresql.org/pgsql-hackers/2005-04/msg00565.php

On Thu, Apr 21, 2005 at 03:33:05PM -0400, Dave Chapeskie wrote:
> On Thu, Apr 21, 2005 at 11:28:43AM -0700, Josh Berkus wrote:
> > Michael,
> > 
> > > ....Every five minutes, DBCC INDEXDEFRAG will report to the user an
> > > estimated percentage completed. DBCC INDEXDEFRAG can be terminated at
> > > any point in the process, and *any completed work is retained.*"
> > 
> > Keen.  Sounds like something for our TODO list.
> > 
> > -- 
> > Josh Berkus
> > Aglio Database Solutions
> > San Francisco
> 
> See http://archives.postgresql.org/pgsql-general/2005-03/msg01465.php
> for my thoughts on a non-blocking alternative to REINDEX.  I got no
> replies to that message. :-(
> 
> 
> I've almost got a working solution integrated in the backend that does
> correct WAL logging and everything.  (Writing the code to write and
> replay WAL logs for complicated operations can be very annoying!)
> 
> For now I've gone with a syntax of:
> 
>   REINDEX INDEX btree_index_name INCREMENTAL;
> 
> (For now it's not a proper index AM (accessor method), instead the
> generic index code knows this is only supported for btrees and directly
> calls the btree_compress function.)
> 
> It's not actually a REINDEX per-se in that it doesn't rebuild the whole
> index.  It holds brief exclusive locks on the index while it shuffles
> items around to pack the leaf pages fuller.  There were issues with the
> code I attached to the above message that have been resolved with the
> new code.  With respect to the numbers provided in that e-mail the new
> code also recycles more pages than before.
> 
> Once I've finished it up I'll prepare and post a patch.
> 
> -- 
> Dave Chapeskie
> OpenPGP Key ID: 0x3D2B6B34
> 
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-- 
Jim C. Nasby, Database Consultant               decibel(at)decibel(dot)org 
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