
322 4.9 Fundamentals of storage performance
dom. Why waste precious cache memory when you know that there is little
chance that the next page to read is in the cache?
Speaking of cache, remember that the ESE database engine has its own
buffer cache in RAM, and if a recent page has to be fetched, it is more likely
to be fetched from the application-level cache that sits in RAM than from
the controller-level cache that sits, at best, on the PCI bus and, at worst,
behind a host-bus adapter and one of several switches or hubs. My point
here is that you should take advantage and rely on the efficiency of the in-
memory cache for read operations and favor controller-based ...