Re: Performance issue with 8.2.3 - "C" application

From: "Merlin Moncure" <mmoncure(at)gmail(dot)com>
To: "Karl Denninger" <karl(at)denninger(dot)net>
Cc: "Tom Lane" <tgl(at)sss(dot)pgh(dot)pa(dot)us>, pgsql-performance(at)postgresql(dot)org
Subject: Re: Performance issue with 8.2.3 - "C" application
Date: 2007-07-25 03:15:19
Message-ID: b42b73150707242015k615c7018s75cc0b804dbb5677@mail.gmail.com
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On 7/25/07, Karl Denninger <karl(at)denninger(dot)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

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