Answer:
Explanation:
To determine if the given schedule is serializable, we need to check if it is equivalent to some serial schedule.
A serial schedule is a schedule in which all the transactions are executed one after the other, with no interleaving. In other words, a serial schedule is equivalent to running the transactions sequentially, without any concurrency or overlapping.
To check if the given schedule is serializable, we can use the precedence graph method. In this method, we create a precedence graph that represents the dependencies between the transactions in the schedule.
Let's analyze the given schedule step by step and create the precedence graph:
read(A) - no dependencies
read(B) - no dependencies
read(C) - no dependencies
read(A) - no dependencies
write(B) - depends on the read(B) operation
write(B) - depends on the read(B) operation
write(A) - depends on the read(A) operation
write(A) - depends on the read(A) operation
write(D) - no dependencies
write(E) - no dependencies
Precedence Graph:
T1 --> read(A) --> write(A)
\
\
\
--> read(A) --> write(A)
\
\
\
--> read(B) --> write(B)
\
\
\
--> write(B)
\
\
\
--> read(C)
In the precedence graph, each transaction is represented by a node, and the directed edges represent the dependencies between the transactions. If there is an edge from T1 to T2, it means that T1 must complete before T2 can start.
From the precedence graph, we can observe that there is a cycle present, which is T1 -> T2 -> T1. A schedule with a cycle in the precedence graph is not serializable because it indicates a conflict between the transactions.
Therefore, the given schedule is not serializable because it contains a cycle in the precedence graph.
If we want to make the schedule serializable, we need to ensure that there are no conflicting operations between transactions. One way to achieve this is by using concurrency control mechanisms like locks or isolation levels in a database management system.
