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From: Andres Freund <andres@2ndquadrant.com>
To: Merlin Moncure <mmoncure@gmail.com>
Cc: Дмитрий Дегтярёв <degtyaryov@gmail.com>
Cc: postgres performance list <pgsql-performance@postgresql.org>
Subject: Re: Cpu usage 100% on slave. s_lock problem.
Date: Tue, 17 Sep 2013 15:43:48 +0200
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On 2013-09-17 08:40:23 -0500, Merlin Moncure wrote:
> > If you ever get into the situation I mistakenly referred to again, I'd
> > strongly suggest recompling postgres with -fno-omit-frame-pointer. That
> > makes hierarchical profiles actually useful which can help tremendously
> > with diagnosing issues like this...
> 
> We may get an opportunity to do that.  I'm curious enough about the
> THP compaction issues that Kevin mentioned to to maybe consider
> cranking buffers again.  If I do that, it will be with strict
> instructions to the site operators to catch a profile before taking
> further action.

The THP issues should be very clearly diagnosable because a good part of
the time will be spent in the kernel. Lots of spinlocking there, but the
function names are easily discernible from pg's code.

Greetings,

Andres Freund

-- 
 Andres Freund	                   http://www.2ndQuadrant.com/
 PostgreSQL Development, 24x7 Support, Training & Services


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  Subject: Re: Cpu usage 100% on slave. s_lock problem.
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