Explanation:Checkpoints are introduced to reduce overheads caused by the log-based recovery. 4. Which of the following protocols ensures conflict serializability and safety from deadlocks?
A. Two-phase locking protocol
B. Time-stamp ordering protocol
C. Graph based protocol
D. Both (a) and (b) above
Answer:A
Explanation:Checkpoints are introduced to reduce overheads caused by the log-based recovery. 4. Which of the following protocols ensures conflict serializability and safety from deadlocks?
A. Two-phase locking protocol B. Time-stamp ordering protocol C. Graph based protocol D. Both (a) and (b) above
Explanation:Time-stamp ordering protocol ensures conflict serializability and safety from deadlocks. 5. Which of the following is the block that is not permitted to be written back to the disk?