From: Alvaro Herrera <alvherre@commandprompt.com>
To: Katsuhiko Okano <okano.katsuhiko@oss.ntt.co.jp>
Cc: pgsql-hackers@postgresql.org
Subject: Re: poor performance with Context Switch Storm at TPC-W.
Date: Tue, 11 Jul 2006 09:59:51 -0400
Message-ID: <20060711135951.GA3995@surnet.cl> (raw)
In-Reply-To: <200607112009.FED09315.TLPPUBIBOPuVLJL@oss.ntt.co.jp>
References: <200607112009.FED09315.TLPPUBIBOPuVLJL@oss.ntt.co.jp>
Katsuhiko Okano wrote:
> I suspected conflict of BufMappingLock.
> but, collected results are seen,
> occurrence of CSStorm and the increase of BufMappingLock counts
> seem not to correspond.
> Instead, SubtransControlLock and SubTrans were increasing.
> I do not understand what in the cause of CSStorm.
Please see this thread:
http://archives.postgresql.org/pgsql-hackers/2005-11/msg01547.php
(actually it's a single message AFAICT)
This was applied on the 8.2dev code, so I'm surprised that 8.2dev
behaves the same as 8.1.
Does your problem have any relationship to what's described there?
I also wondered whether the problem may be that the number of SLRU
buffers we use for subtrans is too low. But the number was increased
from the default 8 to 32 in 8.2dev as well. Maybe you could try
increasing that even further; say 128 and see if the problem is still
there. (src/include/access/subtrans.h, NUM_SUBTRANS_BUFFERS).
--
Alvaro Herrera http://www.CommandPrompt.com/
The PostgreSQL Company - Command Prompt, Inc.
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-hackers@postgresql.org
Cc: alvherre@commandprompt.com, okano.katsuhiko@oss.ntt.co.jp
Subject: Re: poor performance with Context Switch Storm at TPC-W.
In-Reply-To: <20060711135951.GA3995@surnet.cl>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox