OT: Mac OS X disk buffer cache

[Kevin Murphy <murphy@xxxxxxxxxxxxxxx>]

Is there any way of monitoring and/or controlling disk buffer cache 
allocation and usage on Mac OS X?  I'm thinking of two things: 1) being 
able to give PG a more accurate estimate of the size of the cache, and 
2) being able to more quickly flush the cache for testing the 
performance of cold queries.  It would be fantastic for testing to be 
able to signal both PG and the operating system to invalidate their caches.

-Kevin Murphy