GATE CSE 2024 Set 2 | Transactions and Concurrency Question 1 | Database Management System

GATE CSE 2024 Set 2

MCQ (Single Correct Answer)

-0.33

Once the DBMS informs the user that a transaction has been successfully completed, its effect should persist even if the system crashes before all its changes are reflected on disk. This property is called

durability

atomicity

consistency

isolation

GATE CSE 2024 Set 2

MCQ (More than One Correct Answer)

-0.33

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

2PL permits only serializable schedules

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

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

A deadlock is possible with 2PL

GATE CSE 2022

MCQ (Single Correct Answer)

-0.33

Let R_i(z) and W_i(z) denote reac and write operations on a data element z by a transaction T_i, respectively. Consider the schedule S with four transactions.

S : R₄(x), R₂(x), R₃(x), R₁(y), W₁(y), W₂(x), W₃(y), R₄(y)

Which one of the following serial schedules is conflict equivalent to S?

T₁ $$\to$$ T₃ $$\to$$ T₄ $$\to$$ T₂

T₁ $$\to$$ T₄ $$\to$$ T₃ $$\to$$ T₂

T₄ $$\to$$ T₁ $$\to$$ T₃ $$\to$$ T₂

T₃ $$\to$$ T₁ $$\to$$ T₄ $$\to$$ T₂

GATE CSE 2019

MCQ (Single Correct Answer)

-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?

Both I and II

I only

II only

Neither I nor II