Free Mock Test : DBMS (Database Management System) : Concurrency Control (Test 1)

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Free Mock Test - DBMS (Database Management System) : Concurrency Control (Test 1)

As competitive exams and university assessments approach, Concurrency Control in DBMS (Database Management System) has emerged as one of the most important and frequently tested topics for students preparing for technical and computer science examinations. Experts in Database Management System note that questions related to concurrency control are increasingly appearing in exams such as GATE, UGC NET, NIC ,Competative exam and various university-level tests. The concept plays a crucial role in ensuring the correct execution of multiple transactions simultaneously without data inconsistency.

Total Questions : 20

Timer : sec

Question : Which of the following best describes the main advantage of the Thomas Write Rule over basic timestamp ordering?

Guarantees conflict serializability

Eliminates the need for timestamps

Reduces unnecessary transaction aborts

Prevents all concurrency anomalies

Question : Why is the Thomas Write Rule considered more flexible than the basic timestamp ordering protocol?

It allows dirty reads

It ignores certain obsolete write operations

It avoids using read timestamps

It enforces strict locking

Question : Which type of serializability is always ensured by the Thomas Write Rule?

Conflict serializability

View serializability

Strict serializability

Recoverability

Question : Which of the following is NOT a characteristic of validation-based protocol?

Uses local copies during execution

Requires locking of data items

No cascading rollback

Assumes low transaction interference

Question : Which scenario leads to poor performance of validation-based protocols?

Low concurrency

High number of read-only transactions

Frequent conflicts among transactions

Absence of timestamps

Question : Why is the timestamp of the validation phase often used for serialization order?

Because read phase determines conflicts

Because validation phase decides commit or rollback

Because write phase is longest

Because timestamps are only assigned at the end

Question : In a validation-based protocol, which phase determines whether a transaction will commit or rollback?

Read Phase

Write Phase

Validation Phase

Execution Phase

Question : Why are older transactions given higher priority in Timestamp Ordering?

To maximize throughput

To avoid starvation

To maintain serializability based on timestamp order

To reduce rollback frequency

Question : Which statement is NOT correct about Timestamp Ordering Protocol?

It ensures conflict serializability

It uses timestamps to order transactions

It always produces recoverable schedules

Older transactions have higher priority

Question : Which of the following ensures that the Timestamp Ordering Protocol is deadlock-free?

Use of locks before execution

Transactions wait for each other

Transactions are rolled back instead of waiting

Strict two-phase locking

Question : In 2PL, the point where a transaction has acquired all required locks and enters shrinking phase is called:

Commit point

Lock point

Deadlock point

Synchronization point

Question : Which of the following problems can still occur in basic lock-based protocols (including 2PL)?

Lost update anomaly

Deadlock

Dirty read always

Starvation always

Question : What is the main difference between 2PL and Strict 2PL?

Strict 2PL allows lock acquisition in shrinking phase

Strict 2PL releases locks immediately after use

Strict 2PL holds locks until transaction commits

2PL prevents cascading aborts

Question : Which protocol ensures deadlock prevention by requesting all locks before execution begins?

Simplistic Lock Protocol

Strict 2PL

Pre-claiming Lock Protocol

Basic 2PL

Question : Which of the following statements about Two-Phase Locking (2PL) is correct?

Locks can be acquired and released at any time

No locks can be released in the growing phase

New locks can be acquired in the shrinking phase

Locks are released before all locks are acquired

Question : Which concurrency control technique allows transactions to proceed without locks initially and checks conflicts at commit time?

Two-phase locking

Timestamp ordering

Optimistic concurrency control

Deadlock detection

Question : Which of the following statements about Two-Phase Locking (2PL) is correct?

Locks can be acquired and released at any time

Once a lock is released, no new lock can be acquired

Locks are released before all are acquired

It prevents deadlocks completely

Question : Which anomaly is NOT possible under Serializable isolation level?

Dirty read

Lost update

Phantom read

All of the above

Question : In timestamp ordering protocol, a transaction is rolled back if:

It violates locking protocol

Its timestamp is smaller than the write timestamp of the data item

It tries to access a locked data item

It commits before another transaction

Question : Which of the following schedules is recoverable but not cascadeless?

A schedule where transactions read only committed data

A schedule where a transaction commits before the transaction it depends on

A schedule where a transaction reads uncommitted data but commits after the writer commits

A schedule where all transactions follow strict two-phase locking

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