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