Simon Riggs <simon@2ndquadrant.com> writes:
> The LRU moves each time we do FileRead or FileWrite, not just on
> open/close operations.
Sure, but those still require kernel calls, so the cost of a couple of
pointer swings is negligible. There's no way that the logical
complexity of sometimes maintaining LRU and sometimes not is going
to be repaid with a useful (or even measurable) speedup.
regards, tom lane