DBMS solved MCQ - Advantages of concurrent execution of multiple transactions

Multiple choices questions in DBMS, Transaction states in database, What are the advantages of concurrent execution of transactions? How do we improve the transaction throughput in RDBMS? How can we reduce the waiting time of smaller transactions?

DBMS MCQ - System crash and state of a transaction

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1. Transaction-processing systems usually allow multiple transactions to run concurrently. Which of the following best suits as the advantage(s) of allowing concurrent execution of transactions? 

a) Improved transaction throughput

b) Reduced execution complexity

c) Serializability

d) Reduced waiting time

Answer: (a) Improved transaction throughput and (d) Reduced waiting time Improved transaction throughput - Permitting multiple transactions to execute in parallel will increase the number of transaction executed. The parallelism of the CPU and the IO system can be used to handle concurrent execution of transactions. Reduced waiting time – the short transaction need not wait for the longer ones to complete if they are permitted to execute concurrently. Concurrent execution reduces the unpredictable delays in running transactions. Moreover, it also reduces the average response time: the average time for a transaction to be completed after it has been submitted. How would we improve the transaction throughput? By permitting multiple transactions to work in parallel. What is transaction throughput? Number of transactions executed per second How do we reduce waiting time of smaller transactions? When we permit multiple transactions to work simultaneously, smaller transactions need not wait for the longer one to finish. [Smaller transactions may have to wait for longer one to finish if we permit them to execute serially, ie, one after the other]

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What will happen to a transaction if a system crash has occurred during its execution?

List down the advantages of permitting multiple transactions to execute simultaneously

What is transaction throughput?

Can we permit multiple transactions to execute in parallel?

DBMS Solved MCQ, Database management system solved mcq, transaction management system solved mcq, transaction states solved mcq, transaction mcq

DBMS MCQ - Timestamp ordering protocol is free from deadlock - Why

Multiple choices questions in DBMS, Is timestamp ordering protocol free from deadlock? Why do we say that the timestamp ordering protocol is free from deadlock? Concurrency control in DBMS

DBMS MCQ - Timestamp ordering protocol

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1. Timestamp ordering protocol is said to be free from deadlock because of this reason.

a) It is cascade free

b) It guarantees serializability

c) No transaction is made to wait

d) Every write operation updates the W-timestamp of the data item

Answer: (c) No transaction is made to wait In timestamp ordering protocol, a transaction is either permitted to execute the operation or rolled back. No transaction is made to wait for some other transaction. A transaction is permitted to execute in all the following cases and rolled back otherwise; A transaction T that tries to execute read(Q) operation will be permitted if and only if the timestamp(T) >= W-timestamp(Q). That is, T is permitted to execute if it is started after a successful write on Q by some transactions. A transaction T that tries to execute write(Q) operation will be permitted if the timestamp(T) is greater than both the R-timestamp(Q) and W-timestamp(Q). That is, T is permitted to write a data item which was read/write by older transactions.

 

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Concurrency control in dbms

Quiz questions with answers on DBMS concepts

Why do we say that the timestamp ordering protocol is free from deadlock?

No transactions are made to wait in timestamp ordering protocol. How is this achieved?

How does timestamp ordering protocol work?

Schedules under timestamp ordering protocol are deadlock free

Can deadlock happen in schedules that uses timestamp ordering protocol?