Solution:
Log in with sysdba, execute show parameter job_queue_process to see if the result is 0
If this is the reason, you can modify this parameter
ALTER SYSTEM SET job_queue_processes = 100;
summary
1) The job_queue_processes parameter determines the total number of processes that the job job can use.
2) When this parameter is 0, no job will be executed. It is recommended to set this value reasonably and at least greater than 1.
3) For the job running time, the interval and startup time should be set as reasonable as possible.
4) If there are many jobs running at the same time, too small parameter value will cause the job to have to wait. If the parameter value is too large, it will consume more system resources.
5) The value range of job_queue_processes is 0 to 1000, and the total number of job processes that can be created is determined by the job_queue_processes parameter.
6) When job_queue_processes is greater than 1, and when jobs are executed in parallel, at least one of them is a coordinating process. Its total will not exceed the value of job_queue_processes.
7) The value of the job_queue_processes parameter is and DBMS_JOB is shared with DBMS_SCHEDULER.
8) The job_queue_processes parameter, when the value is set to 0, the job created in any way will not run.
9) For job_queue_processes with a non-zero value, the number of job sub-processes depends on the available resources, how the resources are configured, and the number of jobs currently running.
10) In addition, the scheduler jobs method is also limited by the setting of the scheduler attribute MAX_JOB_SLAVE_PROCESSES.
11) max_job_slave_processes can be set by DBMS_SCHEDULER.SET_SCHEDULER_ATTRIBUTE