Operating System Support for Database Management

• Buffer pool management: Need an OS that allows prefetch advice (not sequential), block management advice (not LRU), and selected force out (push intentions list and commit flag to disk in the proper order).
• File system: Need an OS that provides DBMS facilities as lower level objects and character arrays as higher level ones, not vice versa. Also need physical contiguity of logical blocks and a single tree to manage data (instead of 3 separate ones for file blocks, directories, B-trees, etc).
• Scheduling, Process Management, and Interprocess Communication: OS is fundamentally "process per user" (as opposed to server model). [See Lauer and Needham paper]. Basic problem is overhead in some operating systems of task switches and messages. Other problems: convoy phenomenon for critical sections, various server architectures duplicate OS services. Need an OS with cheaper facilities or special fast path functions for DBMS consumers.
• Consistency control: Need to have buffering, concurrency control, and crash recovery all either in OS or in user space. Other problems: need finer-granularity locking.
• Paged virtual memory: problems with binding files (whole or chunks) to user's paged virtual address space, and buffering.