Re: Ответ: [HACKERS] Possible performance improvement: buffer replacement policy

"Mikheev, Vadim"  writes:
> Excuse me but what is LRU-2?

Like LRU, but using time to second most recent reference, instead of
most recent reference, to sort the buffers for recycling.  This gives
a more robust statistic about how often the page is actually being
touched.  (Or that's the theory anyway.)

> I know that in Oracle unused buffers are not in
> simple LRU list: Oracle tries to postpone writes
> as long as possible -:)

Manage dirty buffers separately from clean ones, you mean?  Hm, we could
do that.  With WAL it might even make sense, though before we tended to
flush dirty buffers so fast it would hardly matter.

			regards, tom lane