job_queue_interval and scheduled task parameters.

Oracle Database Tips by Donald Burleson

The job_queue_interval parameter is an important component for any database that uses scheduled jobs, either as part of a job stream (scheduled via dbms_scheduler) or via the obsolete dbms_job package. 

We also have internal scheduled tasks (e.g. automated scheduled statistics collection, job queues) that are scheduled within Oracle.

Other parameters that influence scheduled tasks include queue schedules, used by Oracle advanced Queuing (AQ).  Avoiding the ORA-25228 error include changes to your current usage of the wait_time and first_message options?

The O'Reilly book on PL/SQL Built-in Packages: notes on job_queue_interval:

"The INIT.ORA parameter JOB_QUEUE_INTERVAL controls how long the SNP processes "sleep" (in seconds) between catalog checks.

Setting the interval too low can cause unnecessary overhead as SNP processes constantly check the catalog. Setting the interval too high can keep jobs from executing at the expected time if an SNP process does not awaken promptly enough. The proper balance will depend on the specific mix of jobs in a given environment. For most purposes, the default setting of 60 seconds is adequate."