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