select
  session_id,                              -- SESSION_ID NUMBER
  performance_class,                       -- PERFORMANCE_CLASS VARCHAR2(32)
  work_request_class,                      -- WORK_REQUEST_CLASS VARCHAR2(32)
  hop_count,                               -- HOP_COUNT NUMBER
  pc_unknown,                              -- PC_UNKNOWN NUMBER
  service_name,                            -- SERVICE_NAME VARCHAR2(64)
  module,                                  -- MODULE VARCHAR2(48)
  action,                                  -- ACTION VARCHAR2(32)
  username,                                -- USERNAME VARCHAR2(30)
  program                                  -- PROGRAM VARCHAR2(64)
from
  gv$calltag
where
  inst_id = USERENV('Instance')