Locking is critical for providing high concurrency for any database — you cannot fully utilize your hardware if locking is throttling its use. This talk explores all aspects of locking in Postgres by showing queries and their locks; covered lock types include row, table, shared, exclusive, and advisory lock types. The high concurrency provided by Multiversion Concurrency Control (MVCC) is also covered.
Bruce Momjian is a Postgres Core Team member and is one of the founders of the Postgres Development group. He is a senior Database Architect @ EnterpriseDB.