Re: stats collector process high CPU utilization

From: "Merlin Moncure" <mmoncure(at)gmail(dot)com>
To: "Tom Lane" <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: "Benjamin Minshall" <minshall(at)intellicon(dot)biz>, pgsql-performance(at)postgresql(dot)org
Subject: Re: stats collector process high CPU utilization
Date: 2007-03-01 21:58:20
Message-ID: b42b73150703011358p7dfe77dft85ba7f3cdd3ce160@mail.gmail.com
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On 3/1/07, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> Benjamin Minshall <minshall(at)intellicon(dot)biz> writes:
> > Tom Lane wrote:
> >> It's sounding like what you had was just transient bloat, in which case
> >> it might be useful to inquire whether anything out-of-the-ordinary had
> >> been done to the database right before the excessive-CPU-usage problem
> >> started.
>
> > I don't believe that there was any unusual activity on the server, but I
> > have set up some more detailed logging to hopefully identify a pattern
> > if the problem resurfaces.
>
> A further report led us to realize that 8.2.x in fact has a nasty bug
> here: the stats collector is supposed to dump its stats to a file at
> most every 500 milliseconds, but the code was actually waiting only
> 500 microseconds :-(. The larger the stats file, the more obvious
> this problem gets.

I think this explains the trigger that was blowing up my FC4 box.

merlin

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