Oracle Materialized View
You need to set JOB_QUEUE_PROCESSES to a positive number in order to enable database jobs to run. JOB_QUEUE_PROCESSES controls the number of jobs that are allowed to run simultaneously so if you set the parameter to 1, only 1 job could run at a time. If you're going to be creating multiple materialized views that you want to refresh at approximately the same time or if you are potentially going to be creating additional jobs, you may want to set this parameter to a value greater than 0.