What is optimistic locking and how does it work in databases?

What is optimistic locking and how does it work in databases?

Optimistic locking is a concurrency control method used in databases to prevent conflicts when multiple transactions are trying to update the same data. It assumes that conflicts are rare and allows transactions to proceed without locking the data until they are ready to commit.

Can you explain how optimistic locking differs from pessimistic locking?

Sure! Optimistic locking allows transactions to proceed without locking resources, checking for conflicts only at commit time. In contrast, pessimistic locking locks resources as soon as they are accessed, preventing other transactions from modifying them until the lock is released.

Which databases support optimistic locking?

Many databases support optimistic locking, including PostgreSQL, MySQL, and Microsoft SQL Server. They typically implement it using versioning or timestamps to track changes.

What are the advantages of using optimistic locking?

The main advantages include improved performance in low-contention scenarios, reduced locking overhead, and better scalability since it allows more concurrent transactions.