On Sat, 2003-01-25 at 23:34, Tom Lane wrote:
> pgsql.spam@vinz.nl writes:
> > If one were certain his OS wouldn't do any re-ordering of writes, would it be
> > safe to run with fsync = off? (not that I'm going to try this, but I'm just
> > curious)
>
> I suppose so ... but if your OS doesn't do *any* re-ordering of writes,
> I'd say you need a better OS. Even in Postgres, we'd often like the OS
> to collapse multiple writes of the same disk page into one write. And
> we certainly want the various writes forced by a sync() to be done with
> some intelligence about disk layout, not blindly in order of issuance.
And anyway, wouldn't SCSI's Tagged Command Queueing override it all,
no matter if the OS did re-ordering or not?
But then, it really means it when it says that fsync() succeeds, so does
TCQ matter in this case?
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| Ron Johnson, Jr. mailto:ron.l.johnson@cox.net |
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