Strict two-phase locking (2PL) is a concurrency control method used by many database systems to prevent conflicts and ensure transaction serializability. In strict 2PL, transactions must lock all the required data before executing any updates, and these locks are held until the end of the transaction.
There are several reasons why strict 2PL is commonly used in database systems:
Simplicity: Strict 2PL is a relatively simple concurrency control method that is easy to implement and understand. This makes it an attractive choice for many database system developers.
Serializability: Strict 2PL ensures that transactions execute serially, which guarantees that the database remains in a consistent state. This is an important property for many applications, such as banking systems, where incorrect data can have serious consequences.
Deadlock prevention: Strict 2PL can help prevent deadlocks, which can occur when two transactions are waiting for each other's locks to be released. By acquiring all the required locks at the beginning of the transaction, strict 2PL ensures that no transactions can block each other.
Performance: Although strict 2PL can be more restrictive than other concurrency control methods, it can still be efficient if the database system is well-designed. Many database systems use optimizations such as lock escalation and lock release to improve performance.
Overall, strict 2PL is a widely used concurrency control method in database systems because of its simplicity, serializability, deadlock prevention, and potential for good performance. However, it may not always be the best choice for every application, and alternative methods such as optimistic concurrency control may be more appropriate in some cases.
