Re: O_DIRECT setting

On Thu, Sep 30, 2004 at 07:02:32PM +1200, Guy Thornley wrote:
> Sorry about the belated reply, its been busy around here.
>
> > > Incidentally, postgres heap files suffer really, really bad fragmentation,
> > > which affects sequential scan operations (VACUUM, ANALYZE, REINDEX ...)
> > > quite drastically. We have in-house patches that somewhat alleiviate this,
> > > but they are not release quality. Has anybody else suffered this?
> > >
> >
> > Any chance I could give those patches a try? I'm interested in seeing
> > how they may affect our DBT-3 workload, which execute DSS type queries.
>
> Like I said, the patches are not release quality... if you run them on a
> metadata journalling filesystem, without an 'ordered write' mode, its
> possible to end up with corrupt heaps after a crash because of garbage data
> in the extended files.
>
> If/when we move to postgres 8 I'll try to ensure the patches get re-done
> with releasable quality
>
> Guy Thornley

That's ok, we like to help test and proof things, we don't need patches to be
release quality.

Mark