From: Andrew Dunstan <andrew@dunslane.net>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: pgsql-perform <pgsql-performance@postgresql.org>
Subject: Re: backend suddenly becomes slow, then remains slow
Date: Fri, 14 Dec 2012 15:16:19 -0500
Message-ID: <50CB8913.8050202@dunslane.net> (raw)
In-Reply-To: <5309.1355514960@sss.pgh.pa.us>
References: <50CB7284.3020008@pgexperts.com>
<5309.1355514960@sss.pgh.pa.us>
List-Unsubscribe: <mailto:majordomo@postgresql.org?body=unsub%20pgsql-performance>
On 12/14/2012 02:56 PM, Tom Lane wrote:
> Andrew Dunstan <andrew.dunstan@pgexperts.com> writes:
>> One of my clients has an odd problem. Every so often a backend will
>> suddenly become very slow. The odd thing is that once this has happened
>> it remains slowed down, for all subsequent queries. Zone reclaim is off.
>> There is no IO or CPU spike, no checkpoint issues or stats timeouts, no
>> other symptom that we can see. The problem was a lot worse that it is
>> now, but two steps have alleviated it mostly, but not completely: much
>> less aggressive autovacuuming and reducing the maximum lifetime of
>> backends in the connection pooler to 30 minutes.
>> It's got us rather puzzled. Has anyone seen anything like this?
> Maybe the kernel is auto-nice'ing the process once it's accumulated X
> amount of CPU time?
>
>
That was my initial thought, but the client said not. We'll check again.
cheers
andrew
--
Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-performance
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-performance@postgresql.org
Cc: andrew@dunslane.net, tgl@sss.pgh.pa.us
Subject: Re: backend suddenly becomes slow, then remains slow
In-Reply-To: <50CB8913.8050202@dunslane.net>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox