What is optimistic locking and how does it work?

What is optimistic locking and how does it work?

Optimistic locking is a concurrency control method used in databases. It allows multiple transactions to occur without locking the data, assuming that conflicts are rare. When a transaction is ready to commit, it checks if the data has been modified by another transaction since it was read. If it has, the transaction is rolled back.

Can you give me an example of how optimistic locking is implemented?

Sure! Imagine a scenario where two users are editing the same document. Each user retrieves the document version. When they try to save their changes, the system checks the document's version. If the version matches what they retrieved, the save is successful. If not, one user will receive a message that their changes cannot be saved due to a conflict.

What are the advantages of using optimistic locking?

The main advantages include reduced locking overhead, improved performance in read-heavy environments, and a better user experience since users can work without waiting for locks to be released.

Are there any downsides to optimistic locking?

Yes, the downsides include potential increased complexity in handling conflicts and the possibility of higher rollback rates if many users are trying to update the same data simultaneously.