If you, like me, have stumbeled into trouble with the Scheduler not running jobs, you might realize that there are several ways to disable the Oracle scheduler. The parameter job_queue_processes is just one of them.
The more cunning one is that there’s a parameter, SCHEDULER_DISABLED, visible in the view dba_scheduler_global_attribute.
It’s only visible when the value is set to true. If it’s false, it doesn’t show. I couldn’t find anything about this in the documentation for 12.1 (https://docs.oracle.com/database/121/ARPLS/d_sched.htm#ARPLS72235), but I stubled upon this old blogpost http://lukestipsandtricks.blogspot.no/2010/04/how-to-disable-dbmsscheduler.html.
To enable/disable the scheduler through this parameter, you use the set_scheduler_attribute procedure in the dbms_scheduler package.
begin dbms_scheduler.set_scheduler_attribute( attribute => 'SCHEDULER_DISABLED', value => 'FALSE' ); end; /
Now – I hope this is a little bit easier to find.