Chapter 10, Problem 8P

Program Plan Intro

Pessimistic locking:

It is one of the locking methods in concurrency control. The lock exists in the transaction until the transaction gets committed or rolled back.

Two-phase locking protocol:

It defined the serializability of the transaction but not prevent deadlocks. The process of locking and unlocking can be done using two phases in this protocol. They are: Growing phase and shrinking phase.

Growing phase:

New lock can be occurred on the transaction without unlocking the data items. The data items are locked in this phase.

Shrinking phase:

This phase used to release all transaction but not provide new lock on the transaction.