Re: fallocate / posix_fallocate for new WAL file creation (etc...)

On Mon, May 13, 2013 at 9:54 PM, Jon Nelson <jnelson+pgsql@jamponi.net> wrote:
> Pertinent to another thread titled
> [HACKERS] corrupt pages detected by enabling checksums
> I hope to explore the possibility of using fallocate (or
> posix_fallocate) for new WAL file creation.
>
> Most modern Linux filesystems support fast fallocate/posix_fallocate,
> reducing extent fragmentation (where extents are used) and frequently
> offering a pretty significant speed improvement. In my tests, using
> posix_fallocate (followed by pg_fsync) is at least 28 times quicker
> than using the current method (which writes zeroes followed by
> pg_fsync).
>
> I have written up a patch to use posix_fallocate in new WAL file
> creation, including configuration by way of a GUC variable, but I've
> not contributed to the PostgreSQL project before. Therefore, I'm
> fairly certain the patch is not formatted properly or conforms to the
> appropriate style guides. Currently, the patch is based on 9.2, and is
> quite small in size - 3.6KiB.
>
> Advice on how to proceed is appreciated.

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https://commitfest.postgresql.org/action/commitfest_view/open

-- 
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
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