Re: fsync or fdatasync

Ragnar Kj�rstad wrote:
> On Tue, Sep 10, 2002 at 11:40:24AM -0400, Bruce Momjian wrote:
> >
> > The original poster was wrong about the default.
> >
> > We use fdatasync where available, and fsync when it is not.
>
> Makes sense.
>
> > We also use
> > O_SYNC on open if it is available.
>
> Why? That will slow tings down...

Actually, no, we are only O_SYNC'ing the WAL writes and sometimes that
is faster because you are not writing then fsyncing, you are just
writing.  The fdatasync only is better than O_SYNC when you are doing
multiple WAL writes before an fdatasync and we normally don't do that.

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