Re: Planner really hates nested loops

Magnus Hagander wrote:
> > > I'm hoping someone can shed some light on these results.
> >
> > Not without a lot more detail on how you *got* the results.
> > What exactly did you do to force the various plan choices?
> > (I see some ridiculous choices of indexscans, for instance,
> > suggesting improper use of enable_seqscan in some cases.)
> > And what's the "cache rows" and "disk rows" stuff, and how do
> > you know that what you were measuring is actually what you
> > think it is? I have zero confidence in Windows-atop-ATA as a
> > platform for measuring disk-related behaviors, because I
> > don't think you can control or even know what caching is going on.
>
> You can control the writeback-cache from Device Manager->(the
> disk)->Policies. And if that is turned off, fsync definitly should write
> through, just as on *nix. (write-cache is on by default, no surprise)
>
> AFAIK, you can't control what is cached for reading.

Are you saying that fsync() doesn't write to the platters by default on
Win32?

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