The undo and redo operations must be _________ to guarantee correct behaviour, even if a failure occurs during recovery process.

• A. Idempotent
• B. Easy
• C. Protected
• D. All of the mentioned

The system periodically performs checkpoints that consists of the following operation(s) ____________

• A. Putting all the log records currently in main memory onto stable storage
• B. Putting all modified data residing in main memory onto stable storage
• C. Putting a log record onto stable storage
• D. All of the mentioned

Consider a transaction T1 that committed prior to checkpoint. The record appears in the log before the record. Any modifications made by T1 must have been written to the stable storage either with the checkpoint or prior to it. Thus at recovery time ____________

• A. There is a need to perform an undo operation on t1
• B. There is a need to perform a redo operation on t1
• C. There is no need to perform an undo and redo operation on t1
• D. All of the mentioned

Serializable schedules are ones where ____________

• A. Concurrent execution of transactions is equivalent to the transactions executed serially
• B. The transactions can be carried out one after the other
• C. A valid result occurs after execution transactions
• D. None of the mentioned

A locking protocol is one that ____________

• A. Governs how locks are acquired
• B. Governs how locks are released
• C. Governs how locks are acquired and released
• D. None of the mentioned

The two phase locking protocol consists of ____________

• A. Growing & shrinking phase
• B. Shrinking & creation phase
• C. Creation & growing phase
• D. Destruction & creation phase

The growing phase is a phase in which?

• A. A transaction may obtain locks, but does not release any
• B. A transaction may obtain locks, and releases a few or all of them
• C. A transaction may release locks, but does not obtain any new locks
• D. A transaction may release locks, and does obtain new locks

The shrinking phase is a phase in which?

• A. A transaction may obtain locks, but does not release any
• B. A transaction may obtain locks, and releases a few or all of them
• C. A transaction may release locks, but does not obtain any new locks
• D. A transaction may release locks, and does obtain new locks

Which of the following concurrency control protocols ensure both conflict serializability and freedom from deadlock? I) 2-phase locking II) Timestamp ordering

• A. I only
• B. Ii only
• C. Both i and ii
• D. Neither i nor ii

A deadlock can be broken by ____________

• A. Abort one or more processes to break the circular wait
• B. Abort all the process in the system
• C. Preempt all resources from all processes
• D. None of the mentioned