From: Tom Lane <tgl@sss.pgh.pa.us>
To: Koichi Suzuki <suzuki.koichi@oss.ntt.co.jp>
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: Wed, 11 Apr 2007 18:48:23 -0400
Message-ID: <6050.1176331703@sss.pgh.pa.us> (raw)
In-Reply-To: <461C3557.6040201@oss.ntt.co.jp>
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>
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
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To: pgsql-hackers@postgresql.org
Cc: tgl@sss.pgh.pa.us, suzuki.koichi@oss.ntt.co.jp, simon@2ndquadrant.com, josh@agliodbs.com, pgsql-patches@postgresql.org
Subject: Re: [HACKERS] Full page writes improvement, code update
In-Reply-To: <6050.1176331703@sss.pgh.pa.us>
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