On Tue, 2008-11-18 at 12:54 -0500, Aidan Van Dyk wrote:
> * Tom Lane <tgl@sss.pgh.pa.us> [081118 12:43]:
> > Aidan Van Dyk <aidan@highrise.ca> writes:
> > The trouble here is to avoid repeated WAL-logging of the same hint bits.
> >
> > (Alvaro's patch tried to do that by depending on another hint bit in the
> > page header, but that seems unsafe if hint bit setters aren't taking
> > exclusive lock.)
>
> And I know it's extra IO. That's why I started the whole thing with a question
> along the lines of "how much extra IO are people going to take" for the sake of
> "guarenteeing" we read exactly what we wrote.
Those that need it will turn it on, those that don't won't.
IO is cheap for those that are going to actually need this feature.
Joshua D. Drake
>
> a.
>
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