Re: fallocate / posix_fallocate for new WAL file creation (etc...) - Mailing list pgsql-hackers

From Robert Haas
Subject Re: fallocate / posix_fallocate for new WAL file creation (etc...)
Date
Msg-id CA+Tgmobbf8KnP6fPHHHkCnCzHEcgih+EgBZV+mE8S6X0S9Ru6Q@mail.gmail.com
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In response to Re: fallocate / posix_fallocate for new WAL file creation (etc...)  (Andres Freund <andres@2ndquadrant.com>)
Responses Re: fallocate / posix_fallocate for new WAL file creation (etc...)  (Greg Smith <greg@2ndQuadrant.com>)
Re: fallocate / posix_fallocate for new WAL file creation (etc...)  (Andres Freund <andres@2ndquadrant.com>)
List pgsql-hackers
On Wed, May 29, 2013 at 10:42 AM, Andres Freund <andres@2ndquadrant.com> wrote:
> FWIW, posix' description about posix_fallocate() doesn't actually say
> *anything* about reading. The guarantee it makes is:
> "If posix_fallocate() returns successfully, subsequent writes to the
> specified file data shall not fail due to the lack of free space on the
> file system storage media.".
>
> http://pubs.opengroup.org/onlinepubs/009696799/functions/posix_fallocate.html
>
> So we don't even know whether we can read. I think that means we need to
> zero the file anyway...

Surely this is undue pessimism.

-- 
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company



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