From: Wu Fengguang <wfg@mail.ustc.edu.cn>
To: blender@jaskom.pl
Cc: pgsql-performance@postgresql.org
Subject: Re: PostgreSQL VACCUM killing CPU
Date: Wed, 10 May 2006 22:17:26 +0800
Message-ID: <347270640.30146@ustc.edu.cn> (raw)
In-Reply-To: <1147167570.494108.284720@i39g2000cwa.googlegroups.com>
References: <1147167570.494108.284720@i39g2000cwa.googlegroups.com>
On Tue, May 09, 2006 at 03:19:08AM -0700, blender@jaskom.pl wrote:
> I have got such problem.
> Im running Postgresql 7.3.2 on Linux 2.6.13.
> What is see when VACCUM is running and killing my CPU is:
>
> Cpu(s): 3.2% us, 0.0% sy, 0.0% ni, 0.0% id, 96.8% wa, 0.0% hi,
> 0.0% si
>
> what i am worry about is "96.8% wa" why is it like that?
It's killing your disk drives instead of CPU(which is mostly _idle_
waiting for I/O completion).
Run this command to get an idea of the I/O activities:
iostat -x 3 3
[AD]Running a kernel patched with adaptive read-ahead may help it:
http://www.vanheusden.com/ara/adaptive-readahead-11.1-2.6.16.5.patch.gz
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To: pgsql-performance@postgresql.org
Cc: wfg@mail.ustc.edu.cn, blender@jaskom.pl
Subject: Re: PostgreSQL VACCUM killing CPU
In-Reply-To: <347270640.30146@ustc.edu.cn>
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