From: Marcello Perathoner <marcello@perathoner.de>
To: Dennis Brouwer <dennis.brouwer@m4n.nl>
Cc: pgsql-admin@postgresql.org
Subject: Re: CPU causes 100% load in user space when ntp client runs and postgresql is under heavy load
Date: Mon, 24 Sep 2012 23:05:03 +0200
Message-ID: <5060CAFF.8040203@perathoner.de> (raw)
In-Reply-To: <CAMfP6GYL4Tkga5MKO9=KR5n9Ht_4Nk3Qk4_K0g8Yug09FoJo7g@mail.gmail.com>
References: <CAMfP6GYL4Tkga5MKO9=KR5n9Ht_4Nk3Qk4_K0g8Yug09FoJo7g@mail.gmail.com>
On 09/24/2012 03:53 PM, Dennis Brouwer wrote:
> Last week I was repeatedly able to run all these tests on the database
> without any issue but recently, all of a sudden at random, some of the
> queries performed a factor 100 less. It may take hours to complete the
> transaction. At the same moment we see a dramatic decrease in IO and the
> CPU is nearly 100% busy in user space.
>
> After days of testing I may have found the cause: the ntp client. If I stop
> the ntp client the problem vanishes.
Any chance you are hitting this known linux bug in conjunction with a
misconfigured ntp server? ie. does a
# date -s now
fix the cpu load?
http://blog.mozilla.org/it/2012/06/30/mysql-and-the-leap-second-high-cpu-and-the-fix/comment-page-1/...http://serverfault.com/questions/403732/anyone-else-experiencing-high-rates-of-linux-server-crashes-...
--
Marcello Perathoner
webmaster@gutenberg.org
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To: pgsql-admin@postgresql.org
Cc: marcello@perathoner.de, dennis.brouwer@m4n.nl
Subject: Re: CPU causes 100% load in user space when ntp client runs and postgresql is under heavy load
In-Reply-To: <5060CAFF.8040203@perathoner.de>
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