A Support for DBMS_JOB in Oracle Database 11g Release 2

In this appendix:

About DBMS_JOB
Moving from DBMS_JOB to Oracle Scheduler

About DBMS_JOB

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.

Configuring DBMS_JOB

The JOB_QUEUE_PROCESSES initialization parameter specifies the maximum number of processes that can be created for the execution of jobs. Beginning with Oracle Database 11g Release 1, 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 disables DBMS_JOB jobs and DBMS_SCHEDULER jobs.

Using Both DBMS_JOB and Oracle Scheduler

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.

If JOB_QUEUE_PROCESSES is 0, both DBMS_JOB and Oracle Scheduler jobs are disabled.

Moving from DBMS_JOB to Oracle Scheduler

This section illustrates some examples of how you can take jobs created with the DBMS_JOB package and rewrite them using Oracle Scheduler, which you configure and control with the DBMS_SCHEDULER package.

Creating a Job

An example of creating a job using DBMS_JOB is the following:

VARIABLE jobno NUMBER;
BEGIN
 DBMS_JOB.SUBMIT(:jobno, 'INSERT INTO employees VALUES (7935, ''SALLY'',
   ''DOGAN'', ''sally.dogan@examplecorp.com'', NULL, SYSDATE, ''AD_PRES'', NULL, 
    NULL, NULL, NULL);', SYSDATE, 'SYSDATE+1');
 COMMIT;
END;
/

An equivalent statement using DBMS_SCHEDULER is the following:

BEGIN
 DBMS_SCHEDULER.CREATE_JOB(
   job_name          =>  'job1',
   job_type          =>  'PLSQL_BLOCK',
   job_action        =>  'INSERT INTO employees VALUES (7935, ''SALLY'',
     ''DOGAN'', ''sally.dogan@examplecorp.com'', NULL, SYSDATE,''AD_PRES'', NULL,
      NULL, NULL, NULL);',
   start_date        =>  SYSDATE,
   repeat_interval   =>  'FREQ = DAILY; INTERVAL = 1');
END;
/

Altering a Job

An example of altering a job using DBMS_JOB is the following:

BEGIN
 DBMS_JOB.WHAT(31, 'INSERT INTO employees VALUES (7935, ''TOM'', ''DOGAN'', 
   ''tom.dogan@examplecorp.com'', NULL, SYSDATE,''AD_PRES'', NULL,
   NULL, NULL, NULL);',
 COMMIT;
END;
/

This changes the action for JOB1 to insert a different value. An equivalent statement using DBMS_SCHEDULER is the following:

BEGIN
 DBMS_SCHEDULER.SET_ATTRIBUTE(
   name          => 'JOB1',
   attribute     => 'job_action',
   value         => 'INSERT INTO employees VALUES (7935, ''TOM'', ''DOGAN'', 
      ''tom.dogan@examplecorp.com'', NULL, SYSDATE, ''AD_PRES'', NULL,
      NULL, NULL, NULL);',
END;
/

Removing a Job from the Job Queue

The following example removes a job using DBMS_JOB, where 14144 is the number of the job being run:

BEGIN
   DBMS_JOB.REMOVE(14144);
COMMIT;
END;
/

Using DBMS_SCHEDULER, you would issue the following statement instead:

BEGIN
   DBMS_SCHEDULER.DROP_JOB('myjob1');
END;
/