check active connections
SELECT pid ,datname as database ,usename as username ,application_name ,client_addr as client_address ,client_hostname ,client_port ,backend_start ,query_start ,query ,state FROM pg_stat_activity WHERE state = 'active' order by datname;
-- don't kill my own connection!
pid <> pg_backend_pid()
-- don't kill the connections to other databases
AND datname = 'medical_center_sm'