MVCC

Multi-Version Concurrency Control

The main advantage of using MVCC multi-version concurrency control over the locking model is that in MVCC, the lock requirements for retrieving (reading) data do not conflict with the lock requirements for writing data, so reads do not block writes, and writes never block reads.

There are also table- and row-level locking mechanisms in databases for applications that cannot easily accept MVCC behavior. However, proper use of MVCC will always provide better performance than locks.