Re: Seeking performance advice and explanation for high I/O on 8.3

On Fri, Sep 4, 2009 at 08:54, Scott Otis<scott.otis@intand.com> wrote:
> Robert Haas <robertmhaas@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/