# 28.3. Viewing Locks

Another useful tool for monitoring database activity is thepg_lockssystem table. It allows the database administrator to view information about the outstanding locks in the lock manager. For example, this capability can be used to:

  • View all the locks currently outstanding, all the locks on relations in a particular database, all the locks on a particular relation, or all the locks held by a particular PostgreSQL session.

  • Determine the relation in the current database with the most ungranted locks (which might be a source of contention among database clients).

  • Determine the effect of lock contention on overall database performance, as well as the extent to which contention varies with overall database traffic.

    Details of thepg_locksview appear inSection 52.74. For more information on locking and managing concurrency with PostgreSQL, refer toChapter 13.