Re: Experimental patch for inter-page delay in VACUUM

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. 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