What is optimistic locking and how is it implemented?

What is optimistic locking and how is it implemented?

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 checks for conflicts only when a transaction is committed.

Can you explain how to implement optimistic locking in a SQL database?

To implement optimistic locking in a SQL database, you typically add a version number or timestamp column to your table. When updating a record, you check that the version number matches the one you retrieved. If it does, you proceed with the update and increment the version number; if not, it means another transaction has modified the record.

What happens if a conflict occurs during the update?

If a conflict occurs, the update will fail, and you can handle it by notifying the user or retrying the transaction. It's essential to manage these conflicts gracefully to ensure a good user experience.

Are there any drawbacks to using optimistic locking?

Yes, while optimistic locking can reduce locking overhead, it may lead to increased transaction failures in high-contention scenarios, requiring more retries and potentially impacting performance.