Answer the following questions:
1. Describe how a typical lock manager is implemented. Why must lock and unlock be atomic operations? What is the difference between a lock and a latch? What are convoys and how should a lock manager handle them?
2. Compare lock downgrades with upgrades. Explain why downgrades violate 2PL but are nonetheless acceptable. Discuss the use of update locks in conjunction with lock downgrades.
3. Contrast the timestamps assigned to restarted transactions when timestamps are used for deadlock prevention versus when timestamps are used for concurrency control.
4. State and justify the Thomas Write Rule.
5. Show that, if two schedules are conflict equivalent, then they are view equivalent.
6. Give an example of a serializable schedule that is not strict.
7. Give an example of a strict schedule that is not serializable.
8. Motivate and describe the use of locks for improved conflict resolution in Optimistic Concurrency Control.