Show current locks (for PosgreSQL < 9.2)

locks.sql

-- Taken from http://wiki.postgresql.org/wiki/Lock_Monitoring
-- (PostgreSQL < 9.2 version)
SELECT bl.pid                 AS blocked_pid,
        a.usename              AS blocked_user,
        ka.current_query       AS blocking_statement,
        now() - ka.query_start AS blocking_duration,
        kl.pid                 AS blocking_pid,
        ka.usename             AS blocking_user,
        a.current_query        AS blocked_statement,
        now() - a.query_start  AS blocked_duration
FROM  pg_catalog.pg_locks         bl
  JOIN pg_catalog.pg_stat_activity a  ON a.procpid = bl.pid
  JOIN pg_catalog.pg_locks         kl ON kl.transactionid = bl.transactionid AND kl.pid != bl.pid
  JOIN pg_catalog.pg_stat_activity ka ON ka.procpid = kl.pid
WHERE NOT bl.granted;