Message-ID: <4714897B.7030108@postgresqlfr.org>
Date: Tue, 16 Oct 2007 11:50:51 +0200
From: =?ISO-8859-1?Q?St=E9phane_Schildknecht?=
	<stephane.schildknecht@postgresqlfr.org>
User-Agent: Thunderbird 1.5.0.13 (X11/20070824)
MIME-Version: 1.0
To: Heikki Linnakangas <heikki@enterprisedb.com>
CC: pgsql-performance@postgresql.org
Subject: Re: Vacuum goes worse
References: <47147AD8.9010704@postgresqlfr.org>
	<47147FAA.7010909@enterprisedb.com>
In-Reply-To: <47147FAA.7010909@enterprisedb.com>
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: 8bit

Heikki Linnakangas a écrit :
> Stéphane Schildknecht wrote:
>   
>> I wonder vacuum verbose would tell me if fsm parameters were not too
>> badly configured, but I can't get the 4 last lines of the output...
>>     
>
> Why not?
>   

I would like to know... Seems like vacuum does not want me to see these
precious line. I really don't know why.
>   
>> Whats's more, I wonder what we could monitor to get some explanation of
>> the recent time increase, and then have a quite-sure way of configuring
>> the server.
>>     
>
> sar or iostat output would be a good start, to determine if it's waiting
> for I/O or what.
>   

Ok, I'll try that.
>
> Increasing checkpoint_segments seems like a good idea then. You should
> increase checkpoint_timeout as well, 180 is just 3 minutes. How much
> concurrent activity is there in the database? 30 pg_xlog files equals
> 512 MB of WAL; that's quite a lot.
>   

I don't know exactly how far, but yes, activity is high.
> Have you changed the vacuum cost delay settings from the defaults?
>   

Not yet.


-- 
Stéphane SCHILDKNECHT
Président de PostgreSQLFr
http://www.postgresqlfr.org