Concurrency Control

Question 2

The locking protocol has 2 stages. Name and describe them.

Answer 2

Phase 1: Growing Phase
transaction may obtain locks
transaction may not release locks
Phase 2: Shrinking Phase
transaction may release locks
transaction may not obtain locks

Question 3

What is strict two phase locking?

Answer 3

Here a transaction must hold all its exclusive locks till it commits/aborts.

Question 4

What is rigorous 2 phased locking

Answer 4

Here all locks are held till commit/abort. In this protocol transactions can be serialized in the order in which they commit.