Message-ID: <4817044A.6000800@Sheeky.Biz>
Date: Tue, 29 Apr 2008 20:49:38 +0930
From: Shane Ambler <pgsql@Sheeky.Biz>
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To: Gauri Kanekar <meetgaurikanekar@gmail.com>
CC: Andrew Sullivan <ajs@commandprompt.com>, pgsql-performance@postgresql.org
Subject: Re: Replication Syatem
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Gauri Kanekar wrote:
> Andrew,
> 
> Can you explain me in detail why u said vacuum full is making the things
> worst.
> We do vacuum full, as vacuum verbose analyse dont regain space for us.
> 

vacuum full stops all access so that the data files can be re-writen 
without the unused space.

normal vacuum will update the records of what space is no longer used so 
that it can then be reused with the next update/insert. Your db size 
will not shrink straight away but it will stop growing until you use all 
the free space left from previous update/delete

The more frequently you do a normal vacuum the less time it will take 
and things will run a lot smoother with your file size growing slowly to 
accommodate new data.

Expanding on what others have mentioned as a drawback of vacuum full - 
you should look at REINDEX'ing as well (maybe one index or table at a 
time). You will most likely find this will reclaim some disk space for 
you as well.


-- 

Shane Ambler
pgSQL (at) Sheeky (dot) Biz

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