Re: Experimental patch for inter-page delay in VACUUM

Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)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