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Date: Fri, 16 Jan 2009 09:25:43 -0600
From: Kenneth Marshall <ktm@rice.edu>
To: Francesco Andreozzi <francesco.andreozzi@gamestorm.it>
Cc: pgsql-admin@postgresql.org
Subject: Re: tuning tips, speed problem
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On Fri, Jan 16, 2009 at 04:18:02PM +0100, Francesco Andreozzi wrote:
> Hi all, i send this mesage because i just made a migration from my old 
> mysql db on a more robust postgres server.
> I'm using version 8.1 on a linux debian 4.0
> i have a dual core XEON 2.33GHz and 2Gb of ram ... 2 disk 15k mirrored
> database works good but the performance are horrible! i hope is my fault of 
> settings.... and this message is just a help request to see whats i missing 
> to set!
> i did only few changes on a default postgresql.conf
> i simply playd with shared buffer... but on a mysql to execute a simple 
> select with an order by the time was jus 1 or 2 seconds ... on this 
> installation the time it's about 10 seconds or more .... and if more than 
> one query is executed at the same time the time increase!
>
> i just add here a show all output to see if somethiong uis wrong ... i hope 
> someone can help me ! i really would like to use postgres on this 
> database!!
>
> Thankyou
> Francesco
>
Francesco,

Try increasing your work_memory value and shared_buffers. 8MB is not very
large on a 2GB system. Also, 8.3.5 is much improved over 8.1.

Cheers,
Ken

> shared_buffers          1000
...
> work_mem                1024