Deadlocks (Cont.) Two-phase locking does not ensure freedom from deadlocks. In addition to deadlocks,there is a possibility of starvation. Starvation occurs if the concurrency control manager is badly designed.For example: A transaction may be waiting for an X-lock on an item, while a sequence of other transactions request and are granted an S-lock on the same item. The same transaction is repeatedly rolled back due to deadlocks. Concurrency control manager can be designed to prevent starvation. Database System Concepts-6th Edition 15.12 @Silberschatz,Korth and SudarshanDatabase System Concepts - 6 15.12 ©Silberschatz, Korth and Sudarshan th Edition Deadlocks (Cont.) Two-phase locking does not ensure freedom from deadlocks. In addition to deadlocks, there is a possibility of starvation. Starvation occurs if the concurrency control manager is badly designed. For example: A transaction may be waiting for an X-lock on an item, while a sequence of other transactions request and are granted an S-lock on the same item. The same transaction is repeatedly rolled back due to deadlocks. Concurrency control manager can be designed to prevent starvation