|Oracle® Database Administrator's Guide
11g Release 2 (11.2)
Part Number E17120-05
DBMS_JOB is a PL/SQL package that you use to schedule jobs. It is replaced by Oracle Scheduler, which is more powerful and flexible. Although Oracle recommends that you switch from
DBMS_JOB to Oracle Scheduler,
DBMS_JOB is still supported for backward compatibility.
JOB_QUEUE_PROCESSES initialization parameter specifies the maximum number of processes that can be created for the execution of jobs. Beginning with Oracle Database release 11g,
JOB_QUEUE_PROCESSES defaults to 1000. The job coordinator process starts only as many job queue processes as are required, based on the number of jobs to run and available resources. You can set
JOB_QUEUE_PROCESSES to a lower number to limit the number of job queue processes. Setting
JOB_QUEUE_PROCESSES to 0 diables
DBMS_JOB and Oracle Scheduler (the Scheduler) use the same job coordinator to start job slaves. You can use the
JOB_QUEUE_PROCESSES initialization parameter to limit the number job slaves for both
DBMS_JOB and the Scheduler. Additionally, you can use the Scheduler attribute
MAX_JOB_SLAVE_PROCESSES to limit the number of job slaves for the Scheduler.
The maximum number of job slave processes for the Scheduler is determined by the lesser of the values of
MAX_JOB_SLAVE_PROCESSES. For example:
JOB_QUEUE_PROCESSES is set to 10 and
MAX_JOB_SLAVE_PROCESSES is set to 20, the job coordinator will start no more than 10 job slave processes to be shared between
DBMS_JOB and the Scheduler.
JOB_QUEUE_PROCESSES is 20 and
MAX_JOB_SLAVE_PROCESSES is 10, the coordinator will start up to 20 job slave processes. The Scheduler can use only 10 of these, but
DBMS_JOB can use all 20.
JOB_QUEUE_PROCESSES is 0, both
DBMS_JOB and Oracle Scheduler jobs are disabled.
Oracle Database Reference for more information about the
JOB_QUEUE_PROCESSES initialization parameter