Re: Performance

On Apr 14, 2011, at 2:49 AM, Claudio Freire <klaussfreire@gmail.com> wrote:
> This particular factor is not about an abstract and opaque "Workload"
> the server can't know about. It's about cache hit rate, and the server
> can indeed measure that.

The server can and does measure hit rates for the PG buffer pool, but to my knowledge there is no clear-cut way for PG
toknow whether read() is satisfied from the OS cache or a drive cache or the platter. 

...Robert