-- To determine if Resource Manager is currently enabled: 
select name, cpu_managed from v$rsrc_plan where is_top_plan = 'TRUE';

-- To determine the history of Resource Manager usage:
select name,
to_char(start_time, 'MON DD HH24:MI') start_time,
to_char(end_time, 'MON DD HH24:MI') end_time,
window_name
from v$rsrc_plan_history order by start_time;

-- This query returns the current consumer group for all sessions
set lines 140
column username format a25
column osuser format a25
select username, osuser, sid, resource_consumer_group from v$session;