Gate2017 cs Q53

0. In a database system, unique time stamps are assigned to each transaction using Lamport’s logical clock. Let TS(T₁) and TS(T₂) be the timestamps of transactions T₁ and T₂ respectively. Besides, T₁ holds a lock on the resource R, and T₂ has requested a conflicting lock on the same resource R. The following algorithm is used to prevent deadlocks in the database system assuming that a killed transaction is restarted with the same timestamp.
if TS(T₂) < TS(T₁) then
T₁ is killed
else T₂ waits.
Assume any transactions that is not killed terminates eventually. Which of the following is TRUE about the database system that uses the above algorithm to prevent deadlocks?

Answer
Comment
Array

Option : A
Explanation :
Given,
if TS(T₂) <TS(T₁) then
T₁ is killed
else T₂ waits.
- T₁ holds a lock on the resource R
- T₂ has requested a conflicting lock on the same resource R
According to algo, TS(T₂) <TS(T₁) then T1 is killed else T2 will wait. So in both cases neither deadlock will happen nor starvation.
Therefore, option A is correct

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