Cc: "Willem Leenen"
	<willem_leenen@hotmail.com>,pgsql-performance@postgresql.org
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Date: Thu, 29 Nov 2012 20:24:26 -0500
From: "Kevin Grittner" <kgrittn@mail.com>
Message-ID: <20121130012426.69300@gmx.com>
MIME-Version: 1.0
Subject: Re: Optimize update query
To: =?iso-8859-1?Q?=22Niels_Kristian_Schj=F8dt=22?=
	<nielskristian@autouncle.com>,sthomas@optionshouse.com
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Sender: pgsql-performance-owner@postgresql.org

Niels Kristian Schjødt wrote:

> Okay, now I'm done the updating as described above. I did the
> postgres.conf changes. I did the kernel changes, i added two
> SSD's in a software RAID1 where the pg_xlog is now located -
> unfortunately the the picture is still the same :-( 

You said before that you were seeing high disk wait numbers. Now it
is zero accourding to your disk utilization graph. That sounds like
a change to me.

> When the database is under "heavy" load, there is almost no
> improvement to see in the performance compared to before the
> changes.

In client-visible response time and throughput, I assume, not
resource usage numbers?

> A lot of both read and writes takes more than a 1000 times as
> long as they usually do, under "lighter" overall load.

As an odd coincidence, you showed your max_connections setting to
be 1000.

http://wiki.postgresql.org/wiki/Number_Of_Database_Connections

-Kevin


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