WorksheetsPBL
Total questions: 20
Worksheet time: 10mins
A system is in a ______ state if there exists a set of transactions such that every transaction in the set is waiting for another transaction in the set.
A. Idle
B. Waiting
C. Deadlock
D. Ready
The deadlock state can be changed back to stable state by using _____________ statement.
A. Commit
B. Rollback
C. Savepoint
D. Deadlock
What are the ways of dealing with deadlock?
A. Deadlock prevention
B. Deadlock recovery
C. Deadlock detection
D. All of the mentioned
When a transaction Ti requests a data item currently held by Tj, Ti is allowed to wait only if it has a timestamp smaller than that of Tj (that is, Ti is older than Tj). Otherwise, Ti is rolled back (dies). This is
A. Wait-die
B. Wait-wound
C. Wound-wait
D. Wait
When a transaction Ti requests a data item currently held by Tj, Ti is allowed to wait only if it has a timestamp larger than that of Tj (that is, Ti is younger than Tj ). Otherwise, Tj is rolled back (Tj is wounded by Ti ). This is
A. Wait-die
B. Wait-wound
C. Wound-wait
D. Wait
The deadlock in a set of the transaction can be determined by
A. Read-only graph
B. Wait graph
C. Wait-for graph
D. All of the mentioned
A deadlock exists in the system if and only if the wait-for graph contains a ___________
A. Cycle
B. Direction
C. Bi-direction
D. Rotation
Selecting the victim to be rollbacked to the previous state is determined by the minimum cost. The factors determining cost of rollback is:
A. How long the transaction has computed, and how much longer the transaction will compute before it completes its designated task.
B. How many more data items the transaction needs for it to complete.
C. How many transactions will be involved in the rollback.
D. All of the mentioned
__________ rollback requires the system to maintain additional information about the state of all the running transactions.
A. Total
B. Partial
C. Time
D. Commit
Which of the following is not a recovery technique?
A. Deferred update
B. Immediate update
C. Two-phase commit
D. Recovery management
Checkpoints are a part of
A. Recovery measures
B. Security measures
C. Concurrency measures
D. Authorization measures
....... deals with soft errors, such as power failures
A. system recovery
B. media recovery
C. database recovery
D. failure recovery
Rollback of transactions is normally used to:
A. recover from transaction failure
B. update the transaction
C. retrieve old records
D. repeat a transaction
A transaction performs on the isolation level of the Read Uncommitted if:
A. A dirty read occurs
B. Non-repeatable read occurs
C. Phantom reads occurs
D. All of the above
Which commands are used to control which users have which privilege over which objects?
A. QUE and QUIST
B. GRANT and REVOKE
C. CASECADE and MVD
D. None of the above
When a deadlock is detected the recovery is normally accomplished by:
A. rollback of the transaction
B. locking of data
C. consistency checking
D. none of these
Which is not a desirable property of a transaction?
A. Isolation
B. Atomicity
C. Durability
D. All are desirable
A directed graph that represents the deadlock is called:
A. cycle graph
B. deadlock graph
C. wait-for graph
D. none of the above
Transaction Throughput is:
A. Elapsed Time between submitting a transaction and receiving a transaction.
B. Average no. of transaction processed per second.
C. No. of resources used by a transaction.
D. None of the above.
The most widely used structure for recording database modification is called as _______
A. Log
B. List
C. Queue
D. Stack
