Re: Experimental patch for inter-page delay in VACUUM

Tom Lane kirjutas P, 02.11.2003 kell 20:00:
> Jan Wieck <JanWieck(at)Yahoo(dot)com> writes:
> > I am currently looking at implementing ARC as a replacement strategy. I
> > don't have anything that works yet, so I can't really tell what the
> > result would be and it might turn out that we want both features.
>
> It's likely that we would. As someone (you?) already pointed out,
> VACUUM has bad side-effects both in terms of cache flushing and in
> terms of sheer I/O load. Those effects require different fixes AFAICS.
>
> One thing that bothers me here is that I don't see how adjusting our
> own buffer replacement strategy is going to do much of anything when
> we cannot control the kernel's buffer replacement strategy.

At least for OpenSource/Free OS'es it would probably be possible to
persuade kernel developers to give the needed control to userspace apps.

So the "take over all RAM" is not the only option ;)

> To get any
> real traction we'd have to go back to the "take over most of RAM for
> shared buffers" approach, which we already know to have a bunch of
> severe disadvantages.
>
> regards, tom lane
>
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