select
  MAXIMUM_CONNECTIONS,                     -- MAXIMUM_CONNECTIONS NUMBER
  MAXIMUM_SESSIONS,                        -- MAXIMUM_SESSIONS NUMBER
  SERVERS_STARTED,                         -- SERVERS_STARTED NUMBER
  SERVERS_TERMINATED,                      -- SERVERS_TERMINATED NUMBER
  SERVERS_HIGHWATER                        -- SERVERS_HIGHWATER NUMBER
from
  GV$SHARED_SERVER_MONITOR
where
  inst_id = USERENV('Instance')