Wish to ask some inisights on why the resmgr:cpu quantum becomes a top wait event right after 2AM when the maintenance window closes (it started at 10PM or prior Date).
the Resource Plan is disabled.
The SID holding this resmgr: cpu quantum wait blocks other session. in AWR this sole SID was active for until 8AM. there is already an observed slowness and hang status of the database. We resorted to switchover the DB to make the system ready for the users.
Still unsure the root cause. the DB is in linux oracle, DB version 11204.