engineering recuitment NIC NIELIT Scientist B 2023 Mock Test DBMS Concurrency Control Timestamp Based Ordering Protocol
In a databse system, let TS(T1) and TS(T2) be the timestamps of transactions T1 and T2 respectively. W-t(X) denotes the largest timestamp of any transaction that executed write(X) successfully and R-t(X) denotes the largest timestamp of any transaction that executed read(X) successfully. Which of the following is False?
1
If transaction T1 issues read(X) operation and TS(T1) < W-t(X) then T1 is rolled back.
2
If transaction T1 issues read(X) operation and TS(T1) > W-t(X) then write operation is executed.
3
If transaction T1 issues write(X) operation and TS(T1) < W-t(X) then T1 is rolled back.
4
All of the above.