So is there anything I can do in 8.3 to help this?  I have tried setting ' 
track_activities', 'track_counts' and 'autovacuum' to 'off' (which has reduced 
CPU and I/O a bit) - but the stats collector process is still using up a good 
deal of CPU and I/O - is there any way to turn stats collecting completely off?

Scott Otis
CIO / Lead Developer
Intand
www.intand.com


-----Original Message-----
From: Magnus Hagander [mailto:mag...@hagander.net] 
Sent: Friday, September 04, 2009 1:19 AM
To: Scott Otis
Cc: Robert Haas; Ivan Voras; pgsql-performance@postgresql.org
Subject: Re: [PERFORM] Seeking performance advice and explanation for high I/O 
on 8.3

On Fri, Sep 4, 2009 at 08:54, Scott Otis<scott.o...@intand.com> wrote:
> Robert Haas <robertmh...@gmail.com>:
>
>> Do you by any chance have a bazillion databases in this cluster?  Can 
>> you do these?
>
>> select sum(1) from pg_database;
>
> 1555

Note that there are two features in 8.4 specifically designed to deal with the 
situation where you have lots of databases and/or lots of tables (depending on 
how many tables you have in each database, this would definitely qualify). They 
both deal with the "pgstats temp file too large generating i/o issue".

First, it will only write the file when it's actually necessary - 8.3 and 
earlier will always write it.

Second, you will have the ability to move the location of the file to a 
different filesystem - specifically intended so that you can move it off to a 
ramdrive.

Could be worth investigating an upgrade for this issue alone. The fact that you 
don't have to struggle with tuning the FSM in 8.4 is another thing that makes 
life a *lot* easier in this kind of installations.


--
 Magnus Hagander
 Me: http://www.hagander.net/
 Work: http://www.redpill-linpro.com/

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