Mark Wong wrote:
> On Thu, 11 Aug 2005 22:11:42 -0400 (EDT)
> Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us> wrote:
> > Tom Lane wrote:
> > > Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us> writes:
> > > >> O_DIRECT is only being used for WAL page writes (or I sure hope so
> > > >> anyway), so shared_buffers should be irrelevant.
> > >
> > > > Uh, O_DIRECT really just enables when open_sync is used, and I assume
> > > > that is not used for writing dirty buffers during a checkpoint.
> > >
> > > I double-checked that O_DIRECT is really just used for WAL, and only
> > > when the sync mode is open_sync or open_datasync. So it seems
> > > impossible that it affected a run with mode fdatasync. What seems the
> > > best theory at the moment is that the grouped-WAL-write part of the
> > > patch doesn't work so well as we thought.
> > Yes, that's my only guess. Let us know if you want the patch to test,
> > rather than pulling CVS before and after the patch was applied.
> Yeah, a patch would be a little easier. :)
OK, patch attached. The code has been cleaned up a little since then but
this is the basic change that should be tested. It is based on CVS of
2005/07/29 03:22:33 GMT.
Bruce Momjian | http://candle.pha.pa.us
pgman(at)candle(dot)pha(dot)pa(dot)us | (610) 359-1001
+ If your life is a hard drive, | 13 Roberts Road
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