What are the differences between MVCC and optimistic locking?

What are the differences between MVCC and optimistic locking?

MVCC, or Multi-Version Concurrency Control, allows multiple versions of data to exist, enabling concurrent access without locking. Optimistic locking, on the other hand, assumes that conflicts are rare and checks for conflicts before committing changes.

Can you explain how MVCC works in databases?

Sure! In MVCC, each transaction sees a snapshot of the database at a specific point in time. When a transaction reads data, it gets the version that was committed before the transaction started, allowing for consistent reads without blocking.

What are the advantages of using optimistic locking?

Optimistic locking is beneficial because it reduces the overhead of locking resources, allowing for higher throughput in systems with low contention. It also simplifies the locking mechanism since it only checks for conflicts at the time of commit.

Are there any downsides to using MVCC?

Yes, while MVCC improves concurrency, it can lead to increased storage usage due to multiple versions of data being kept. Additionally, managing these versions can add complexity to the database system.