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Re: Occasional giant spikes in CPU load

From: "Joshua D(dot) Drake" <jd(at)commandprompt(dot)com>
To: Craig James <craig_james(at)emolecules(dot)com>
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: Occasional giant spikes in CPU load
Date: 2010-06-25 01:01:40
Message-ID: 1277427700.2528.3.camel@jd-desktop.unknown.charter.com (view raw or flat)
Thread:
Lists: pgsql-performance
On Thu, 2010-06-24 at 17:50 -0700, Craig James wrote:
> I'm reviving this question because I never figured it out.  To summarize: At random intervals anywhere from a few times per hour to once or twice a day, we see a huge spike in CPU load that essentially brings the system to a halt for up to a minute or two.  Previous answers focused on "what is it doing", i.e. is it really Postgres or something else?
> 
> Now the question has narrowed down to this: what could trigger EVERY postgres backend to do something at the same time?  See the attached output from "top -b", which shows what is happening during one of the CPU spikes.

checkpoint causing IO Wait.

What does sar say about these times?

Joshua D. Drake


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