Jan Wieck <JanWieck@Yahoo.com> writes:
> Okay, my proposal would be to have a VACUUM mode where it tells the
> buffer manager to only return a page if it is already in memory, and
> some "not cached" if it would have to read it from disk, and simply skip
> the page in that case.
Since no such call is available at the OS level, this would only work
well with very large shared_buffers settings (ie, you try to rely on
PG shared buffers to the exclusion of kernel disk cache). AFAIK the
general consensus is that that's not a good way to run Postgres.
regards, tom lane