PostgreSQL отключить всех пользователь БД

PostgreSQL 9.1 and below:

SELECT pg_terminate_backend(pg_stat_activity.procpid)
FROM pg_stat_activity
WHERE pg_stat_activity.datname = 'TARGET_DB'
 AND procpid <> pg_backend_pid();

PostgreSQL 9.2 and above:

SELECT pg_terminate_backend(pg_stat_activity.pid)
FROM pg_stat_activity
WHERE pg_stat_activity.datname = 'TARGET_DB'
 AND pid <> pg_backend_pid();

отсюда