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 transactions to access the database without locking it, creating a new version of data for each transaction. Optimistic locking, on the other hand, assumes that conflicts are rare and checks for conflicts only at the time of committing the transaction.

Can you explain how MVCC works in practice?

Sure! In MVCC, when a transaction reads data, it gets a snapshot of the data at that moment. If another transaction modifies the data, the original transaction still sees the old version, ensuring consistency without locking.

What are the advantages of using optimistic locking?

Optimistic locking is beneficial in scenarios with low contention, as it reduces the overhead of locking resources. It allows for higher throughput and better performance in read-heavy applications.

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, it may require more complex garbage collection to clean up old versions.