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From: Pierre C <lists@peufeu.com>
To: felix <crucialfelix@gmail.com>
To: Scott Marlowe <scott.marlowe@gmail.com>
Cc: sthomas@peak6.com, "pgsql-performance@postgresql.org" <pgsql-performance@postgresql.org>
Subject: Re: Really really slow select count(*)
Date: Sun, 06 Feb 2011 20:19:17 +0100
Message-ID: <op.vqhxafcueorkce@apollo13> (raw)
In-Reply-To: <AANLkTim+aLaihKbNSsiiL4exgtCeRqCh_50j48jHFDQm@mail.gmail.com>
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	<AANLkTim+aLaihKbNSsiiL4exgtCeRqCh_50j48jHFDQm@mail.gmail.com>


>> I have clustered that table, its still unbelievably slow.
>
> Did you actually delete the old entries before clustering it?  if it's
> still got 4G of old sessions or whatever in it, clustering ain't gonna
> help.

Also, IMHO it is a lot better to store sessions in something like  
memcached, rather than imposing this rather large load on the main  
database...

PS : if your site has been down for 6 hours, you can TRUNCATE your  
sessions table...



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