Bruce Momjian <pgman@candle.pha.pa.us> writes:
> Now, the disadvantages of large kernel cache, small PostgreSQL buffer
> cache is that data has to be transfered to/from the kernel buffers, and
> second, we can't control the kernel's cache replacement strategy, and
> will probably not be able to in the near future, while we do control our
> own buffer cache replacement strategy.
The intent of the posix_fadvise() work is to at least provide a
few hints about our I/O patterns to the kernel's buffer
cache. Although only Linux supports it (right now), that should
hopefully improve the status quo for a fairly significant portion of
our user base.
I'd be curious to see a comparison of the cost of transferring data
from the kernel's buffers to the PG bufmgr.
-Neil