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Message-ID: <b42b73150707242015k615c7018s75cc0b804dbb5677@mail.gmail.com>
Date: Wed, 25 Jul 2007 08:45:19 +0530
From: "Merlin Moncure" <mmoncure@gmail.com>
To: "Karl Denninger" <karl@denninger.net>
Subject: Re: Performance issue with 8.2.3 - "C" application
Cc: "Tom Lane" <tgl@sss.pgh.pa.us>, pgsql-performance@postgresql.org
In-Reply-To: <46A6BBB1.1020502@denninger.net>
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References: <46A6A549.1040606@denninger.net> <29633.1185331558@sss.pgh.pa.us>
	<46A6BBB1.1020502@denninger.net>

On 7/25/07, Karl Denninger <karl@denninger.net> wrote:
>
>  Yeah, the problem doesn't appear to be there.  As I said, if I look at the
> PS of the system when its bogging, there aren't a whole bunch of processes
> stuck doing these, so while this does take a second or two to come back,
> that's not that bad.
>
>  Its GENERAL performance that just bites - the system is obviously out of
> CPU, but what I can't get a handle on is WHY.  It does not appear to be
> accumulating large amounts of runtime in processes I can catch, but the load
> average is quite high.

8.2.3 has the 'stats collector bug' (fixed in 8.2.4) which increased
load in high concurrency conditions.  on a client's machine after
patching the postmaster load drop from the 4-5 range to 1-2 range on a
500 tps server.  maybe this is biting you?  symptoms are high load avg
and high cpu usage of stats collector process.

merlin