Question 5378 – UGC NET CS 2012 June-Paper2

A transaction manager is one who is responsible for the ACID properties of a transaction.
→ He maintains the log of all transactions and ensures that only each transaction should be either performed completely or not performed at all.
→ Transaction manager ensure consistency preservation by maintaining the before and after database images of a transaction.
→ Multiple transactions can be executed simultaneously but it is the responsibility of transaction manager that the execution of a transaction should not be interfered with by any other transactions executing concurrently. So for that it maintains a appropriate concurrency control.
→ Transaction manager is also responsible for the durability of a transaction that is the changes applied to the database by a committed transaction must persist in the database. These changes must not be lost because of any failure.