Locking: A Technique for C. C.
Concurrency control usually done via locking.
Lock info maintained by a “lock manager”:
- Stores (XID, RID, Mode) triples.
- This is a simplistic view; suffices for now.
- Mode Î {S,X}
- Lock compatibility table:
If a Xact can’t get a lock, it is
suspended on a wait queue.