27.3. Viewing Locks
Another useful tool for monitoring database activity is the
pg_locks
system 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 the
pg_locks
view appear in
Section 52.12
.
For more information on locking and managing concurrency with
PostgreSQL
, refer to
Chapter 13
.