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Message-ID: <463D8E91.4050605@enterprisedb.com>
Date: Sun, 06 May 2007 09:15:13 +0100
From: Heikki Linnakangas <heikki@enterprisedb.com>
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To: Yudhvir Singh Sidhu <ysidhu@gmail.com>
CC: pgsql-performance@postgresql.org
Subject: Re: How to Find Cause of Long Vacuum Times - NOOB Question
References: <463D0BD5.3010404@gmail.com>
In-Reply-To: <463D0BD5.3010404@gmail.com>
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Yudhvir Singh Sidhu wrote:
> Versions:  Postgresql version 8.09 on FreeBSD 6.1
> Situation:  huge amounts of adds and deletes daily. Running daily vacuums
> Problem:  Vacuum times jump up from 45 minutes, or 1:30 minutes to 6+ 
> hours overnight, once every 1 to 3 months.
> Solutions tried:  db truncate - brings vacuum times down. Reindexing 
> brings vacuum times down.
> 
> I know my indexes are getting fragmented and my tables are getting 
> fragmented. I also know that some of my btree indexes are not being used 
> in queries. I also know that using "UNIQUE" in a query makes PG ignore 
> any index.

If the increase in vacuum time is indeed because of index fragmentation, 
upgrading to 8.2 might help. Since 8.2, we vacuum indexes in physical 
order, which speeds it up significantly, especially on fragmented indexes.

-- 
   Heikki Linnakangas
   EnterpriseDB   http://www.enterprisedb.com