1
GATE CSE 2024 Set 2
MCQ (More than One Correct Answer)
+1
-0

Which of the following statements about the Two Phase Locking (2PL) protocol is/are TRUE?

A

2PL permits only serializable schedules

B

With 2PL, a transaction always locks the data item being read or written just before every operation and always releases the lock just after the operation

C

With 2PL, once a lock is released on any data item inside a transaction, no more locks on any data item can be obtained inside that transaction

D

A deadlock is possible with 2PL

2
GATE CSE 2021 Set 1
MCQ (More than One Correct Answer)
+1
-0

Suppose a database system crashes again while recovering from a previous crash. Assume checkpointing is not done by the database either during the transactions or during recovery.

Which of the following statements is/are correct?

A
The same undo and redo list will be used while recovering again.
B
The database will become inconsistent.
C
All the transactions that are already undone and redone will not be recovered again.
D
The system cannot recover any further.
3
GATE CSE 2019
MCQ (Single Correct Answer)
+1
-0.33
Consider the following two statements about database transaction schedules:

I. Strict two-phase locking protocol generates conflict serializable schedules that are also recoverable.

II. Timestamp-ordering concurrency control protocol with Thomas Write Rule can generate view serializable schedules that are not conflict serializable.

Which of the above statements is/are TRUE?
A
Both I and II
B
I only
C
II only
D
Neither I nor II
4
GATE CSE 2016 Set 2
MCQ (Single Correct Answer)
+1
-0.3
Suppose a database schedule $$S$$ involves transactions $${T_1},\,...,\,{T_n}.$$ Construct the precedence graph of $$S$$ with vertices representing the transactions and edges representing the conflicts. If $$S$$ is serializable, which one of the following orderings of the vertices of the precedence graph is guaranteed to yield a serial schedule?
A
Topological order
B
Depth-first order
C
Breadth-first order
D
Ascending order of transaction indices
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