Showing deadlocked processes with Postgres

If you need to find out which Postgres processes are blocking your query then you can use the select query like the one below:

SELECT
   h.pid AS blocker_pid,
   w.pid AS blockee_pid
FROM
   pg_locks h,
   pg_locks w
WHERE
   h.granted AND
   NOT w.granted AND
   (
      (h.relation = w.relation AND h.database = w.database)
      OR
      h.transaction = w.transaction
   )
;

Last updated: 02/02/2007