From: Koichi Suzuki <suzuki.koichi@oss.ntt.co.jp>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Simon Riggs <simon@2ndquadrant.com>
Cc: josh@agliodbs.com
Cc: pgsql-hackers@postgresql.org
Cc: pgsql-patches@postgresql.org
Subject: Re: [HACKERS] Full page writes improvement, code update
Date: Thu, 12 Apr 2007 10:40:04 +0900
Message-ID: <461D8DF4.1070200@oss.ntt.co.jp> (raw)
In-Reply-To: <6050.1176331703@sss.pgh.pa.us>
References: <460886E8.6040907@oss.ntt.co.jp>
<4609CAC3.7060008@oss.ntt.co.jp>
<1175072848.4386.323.camel@silverbirch.site>
<200703291145.28574.josh@agliodbs.com>
<1175200117.4386.616.camel@silverbirch.site>
<460C611E.6090800@oss.ntt.co.jp>
<27693.1176226131@sss.pgh.pa.us>
<461C3557.6040201@oss.ntt.co.jp>
<6050.1176331703@sss.pgh.pa.us>
The score below was taken based on 8.2 code, not 8.3 code. So I don't
think the below measure is introduced only in 8.3 code.
Tom Lane wrote:
> Koichi Suzuki <suzuki.koichi@oss.ntt.co.jp> writes:
>> For more information, when checkpoint interval is one hour, the amount
>> of the archived log size was as follows:
>> cp: 3.1GB
>> gzip: 1.5GB
>> pg_compresslog: 0.3GB
>
> The notion that 90% of the WAL could be backup blocks even at very long
> checkpoint intervals struck me as excessive, so I went looking for a
> reason, and I may have found one. There has been a bug in CVS HEAD
> since Feb 8 causing every btree page split record to include a backup
> block whether needed or not. If these numbers were taken with recent
> 8.3 code, please retest with current HEAD.
>
> regards, tom lane
>
--
Koichi Suzuki
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To: pgsql-hackers@postgresql.org
Cc: suzuki.koichi@oss.ntt.co.jp, tgl@sss.pgh.pa.us, simon@2ndquadrant.com, josh@agliodbs.com, pgsql-patches@postgresql.org
Subject: Re: [HACKERS] Full page writes improvement, code update
In-Reply-To: <461D8DF4.1070200@oss.ntt.co.jp>
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