Get the Active Database Sessions

SELECT s.audsid AUDSID,

       i.instance_name "Instance",

       s.machine "Machine",

       s.program "Program",

       s.module "Module",

       s.osuser "User",

       s.process "Process",

       s.status "Status",

       s.logon_time "Logon Time"

  FROM gv$session s, gv$instance i

 WHERE s.audsid > 0 AND s.inst_id = i.inst_id;