02.05.2018 01:37, Peter Geoghegan пишет: > On Tue, May 1, 2018 at 11:58 AM, Robert Haas <robertmh...@gmail.com> wrote: >> I agree that double-counting correlated accesses is a a problem, and I >> agree that we probably want to do something about it. I am skeptical >> that using wall-clock time is the right way to solve that problem >> because it leads to edge effects > > I agree that wall-clock time is a bad approach, actually. If we were > to use wall-clock time, we'd only do so because it can be used to > discriminate against a thing that we actually care about in an > approximate, indirect way. If there is a more direct way of > identifying correlated accesses, which I gather that there is, then we > should probably use it.
I suggest incrementing only once in 1/32 replacements in shared_buffers. I.e. if size of shared_buffers is 1024, and this page were put into shared_buffers as 21200, then next time its usage count will be incremented only after 21232 page were put into shared buffers. And second time only after 21264 page. regards, Yura.
