Re: data on devel code perf dip

Andrew - Supernews wrote:
> On 2005-08-12, Alvaro Herrera <alvherre@alvh.no-ip.org> wrote:
> > In light of this, may I ask whether it makes sense to compare the
> > performance of two runs with similar shared_buffer settings?  With
> > O_DIRECT, I understand from this manpage that the OS is going to do
> > little or no page caching, so shared_buffers should be increased to
> > account for this fact.
> >
> > Am I missing something?
> 
> O_DIRECT should only be being used for the WAL, not for buffer I/O.

And only when open_sync or open_datasync are used.  But the group write
patch is used in all cases, but again only WAL.

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