Pg_readahead uses posix_fadvise, which is included in Greg's patch andI've already posted pg_readahead patch integrated
intothe core.
Integration with snc.rep. will be a separate patch which will be
posted in a couple of days.
2009/1/14 Bruce Momjian <bruce@momjian.us>:
> Koichi Suzuki wrote:
>> Pg_readahead is a tool to prefetch data pages before redoing, based on
>> the contents of archive/active WAL segment. For 8.3 and 8.4 without
>> sync.rep, this works together with restore_command. Pg_readahead
>> analyze WAL segment, schedule and issue posix_fadvise() to prefetch
>> data pages quickly before redoing.
>>
>> Discussions and materials will be found at
>>
>> http://archives.postgresql.org/pgsql-hackers/2008-10/msg01372.php
>>
>> So far, external command implemantation speeds up PITR up to six
>> times! Therefore, overall recovery time can be a little longer than
>> that with FPW.
>
> Now that 8.4 is using fsync, sounds like something that should be
> integrated into the core code, rather than as a /contrib.
>
> --
> Bruce Momjian <bruce@momjian.us> http://momjian.us
> EnterpriseDB http://enterprisedb.com
>
> + If your life is a hard drive, Christ can be your backup. +
>
--
------
Koichi Suzuki