Buffer Management

What
The buffer hides the fact that not all data is in RAM. It is responsible for managing the data from disk so that all features above it do not have to worry where the data is coming from and can focus on doing useful work on the data.

What
The buffer manager is responsible for serving up the correct page that was requested

When Data is in Buffer Pool
If the data is in buffer pool, it is a simple job for the buffer manager to pin the page and return its address

Otherwise

 * 1) Find an open frame. If none exist, choose a frame for replacement according to a buffer replacement policy . If the frame is dirty, write its contents out to disk first
 * 2) Read the data from disk into the buffer frame
 * 3) Pin the page and return the address of that frame