Re: O_DIRECT setting

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