The DBMS_JOB package schedules and manages jobs in the job queue.
Note:
TheDBMS_JOB package has been superseded by the DBMS_SCHEDULER package. In particular, if you are administering jobs to manage system load, you should consider disabling DBMS_JOB by revoking the package execution privilege for users.
For more information, see Chapter 129, "DBMS_SCHEDULER" and "Moving from DBMS_JOB to DBMS_SCHEDULER" in Oracle Database Administrator's Guide.
This chapter contains the following topics:
Security Model
Operational Notes
No specific system privileges are required to use DBMS_JOB. No system privileges are available to manage DBMS_JOB. Jobs cannot be altered or deleted other than jobs owned by the user. This is true for all users including those users granted DBA privileges.
You can execute procedures that are owned by the user or for which the user is explicitly granted EXECUTE. However, procedures for which the user is granted the execute privilege through roles cannot be executed.
Note that, once a job is started and running, there is no easy way to stop the job.
DBMS_JOB supports multi-instance execution of jobs. By default jobs can be executed on any instance, but only one single instance will execute the job. In addition, you can force instance binding by binding the job to a particular instance. You implement instance binding by specifying an instance number to the instance affinity parameter. Note, however, that in Oracle Database 10g Release 1 (10.1) instance binding is not recommended. Service affinity is preferred. This concept is implemented in the DBMS_SCHEDULER package.
The following procedures can be used to create, alter or run jobs with instance affinity. Note that not specifying affinity means any instance can run the job.
To submit a job to the job queue, use the following syntax:
DBMS_JOB.SUBMIT( job OUT BINARY_INTEGER, what IN VARCHAR2, NEXT_DATE IN DATE DEFAULTSYSDATE, interval IN VARCHAR2 DEFAULT 'NULL', no_parse IN BOOLEAN DEFAULT FALSE, instance IN BINARY_INTEGER DEFAULT ANY_INSTANCE, force IN BOOLEAN DEFAULT FALSE);
Use the parameters instance and force to control job and instance affinity. The default value of instance is 0 (zero) to indicate that any instance can execute the job. To run the job on a certain instance, specify the instance value. Oracle displays error ORA-23319 if the instance value is a negative number or NULL.
The force parameter defaults to false. If force is TRUE, any positive integer is acceptable as the job instance. If force is FALSE, the specified instance must be running, or Oracle displays error number ORA-23428.
To assign a particular instance to execute a job, use the following syntax:
DBMS_JOB.INSTANCE( JOB IN BINARY_INTEGER,
instance IN BINARY_INTEGER,
force IN BOOLEAN DEFAULT FALSE);
The FORCE parameter in this example defaults to FALSE. If the instance value is 0 (zero), job affinity is altered and any available instance can execute the job despite the value of force. If the INSTANCE value is positive and the FORCE parameter is FALSE, job affinity is altered only if the specified instance is running, or Oracle displays error ORA-23428.
If the force parameter is TRUE, any positive integer is acceptable as the job instance and the job affinity is altered. Oracle displays error ORA-23319 if the instance value is negative or NULL.
To alter user-definable parameters associated with a job, use the following syntax:
DBMS_JOB.CHANGE( JOB IN BINARY_INTEGER,
what IN VARCHAR2 DEFAULT NULL,
next_date IN DATE DEFAULT NULL,
interval IN VARCHAR2 DEFAULT NULL,
instance IN BINARY_INTEGER DEFAULT NULL,
force IN BOOLEAN DEFAULT FALSE );
Two parameters, instance and force, appear in this example. The default value of instance is null indicating that job affinity will not change.
The default value of force is FALSE. Oracle displays error ORA-23428 if the specified instance is not running and error ORA-23319 if the instance number is negative.
The force parameter for DBMS_JOB.RUN defaults to FALSE. If force is TRUE, instance affinity is irrelevant for running jobs in the foreground process. If force is FALSE, the job can run in the foreground only in the specified instance. Oracle displays error ORA-23428 if force is FALSE and the connected instance is the incorrect instance.
DBMS_JOB.RUN(
job IN BINARY_INTEGER,
force IN BOOLEAN DEFAULT FALSE);
Table 78-1 DBMS_JOB Package Subprograms
| Subprogram | Description |
|---|---|
|
Disables job execution |
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Alters any of the user-definable parameters associated with a job |
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Assigns a job to be run by a instance |
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Alters the interval between executions for a specified job |
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Alters the next execution time for a specified job |
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Removes specified job from the job queue |
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Forces a specified job to run |
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Submits a new job to the job queue |
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Re-creates a given job for export, or re-creates a given job for export with instance affinity |
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Alters the job description for a specified job |
This procedure sets the broken flag. Broken jobs are never run.
DBMS_JOB.BROKEN ( job IN BINARY_INTEGER, broken IN BOOLEAN, next_date IN DATE DEFAULT SYSDATE);
Table 78-2 BROKEN Procedure Parameters
| Parameter | Description |
|---|---|
|
|
Number of the job being run. |
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Job broken: |
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Date of the next refresh. |
Note:
If you set job as broken while it is running, Oracle resets the job's status to normal after the job completes. Therefore, only execute this procedure for jobs that are not running.This procedure changes any of the fields a user can set in a job.
DBMS_JOB.CHANGE ( job IN BINARY_INTEGER, what IN VARCHAR2, next_date IN DATE, interval IN VARCHAR2, instance IN BINARY_INTEGER DEFAULT NULL, force IN BOOLEAN DEFAULT FALSE);
Table 78-3 CHANGE Procedure Parameters
| Parameter | Description |
|---|---|
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Number of the job being run. |
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PL/SQL procedure to run. |
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Date of the next refresh. |
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Date function; evaluated immediately before the job starts running. |
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When a job is submitted, specifies which instance can run the job. This defaults to |
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If this is If this is |
You must issue a COMMIT statement immediately after the statement.
The parameters instance and force are added for job queue affinity. Job queue affinity gives users the ability to indicate whether a particular instance or any instance can run a submitted job.
If the parameters what, next_date, or interval are NULL, then leave that value as it is.
This procedure changes job instance affinity.
DBMS_JOB.INSTANCE ( job IN BINARY_INTEGER, instance IN BINARY_INTEGER, force IN BOOLEAN DEFAULT FALSE);
Table 78-4 INSTANCE Procedure Parameters
| Parameter | Description |
|---|---|
|
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Number of the job being run. |
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When a job is submitted, a user can specify which instance can run the job. |
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If this is |
This procedure changes how often a job runs.
If the job completes successfully, then this new date is placed in next_date. interval is evaluated by plugging it into the statement select interval into next_date from dual;
The interval parameter must evaluate to a time in the future. Legal intervals include:
| Interval | Description |
|---|---|
'sysdate + 7' |
Run once a week. |
'next_day(sysdate,''TUESDAY'')' |
Run once every Tuesday. |
'null' |
Run only once. |
If interval evaluates to NULL and if a job completes successfully, then the job is automatically deleted from the queue.
You must issue a COMMIT statement immediately after the statement.
This procedure removes an existing job from the job queue. This currently does not stop a running job.
This procedure runs job JOB now. It runs it even if it is broken.
Running the job recomputes next_date. See view user_jobs.
This procedure submits a new job. It chooses the job from the sequence sys.jobseq.
DBMS_JOB.SUBMIT ( job OUT BINARY_INTEGER, what IN VARCHAR2, next_date IN DATE DEFAULT sysdate, interval IN VARCHAR2 DEFAULT 'null', no_parse IN BOOLEAN DEFAULT FALSE, instance IN BINARY_INTEGER DEFAULT any_instance, force IN BOOLEAN DEFAULT FALSE);
Table 78-9 SUBMIT Procedure Parameters
| Parameter | Description |
|---|---|
|
|
Number of the job being run. |
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|
PL/SQL procedure to run. |
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Next date when the job will be run. |
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Date function that calculates the next time to run the job. The default is |
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A flag. The default is For example, if you want to submit a job before you have created the tables associated with the job, then set this to |
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When a job is submitted, specifies which instance can run the job. |
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|
If this is |
You must issue a COMMIT statement immediately after the statement.
The parameters instance and force are added for job queue affinity. Job queue affinity gives users the ability to indicate whether a particular instance or any instance can run a submitted job.
This submits a new job to the job queue. The job calls the procedure DBMS_DDL.ANALYZE_OBJECT to generate optimizer statistics for the table DQUON.ACCOUNTS. The statistics are based on a sample of half the rows of the ACCOUNTS table. The job is run every 24 hours:
VARIABLE jobno number;
BEGIN
DBMS_JOB.SUBMIT(:jobno,
'dbms_ddl.analyze_object(''TABLE'',
''DQUON'', ''ACCOUNTS'',
''ESTIMATE'', NULL, 50);'
SYSDATE, 'SYSDATE + 1');
COMMIT;
END;
/
Statement processed.
print jobno
JOBNO
----------
14144
There are two overloaded procedures. The first produces the text of a call to re-create the given job. The second alters instance affinity (8i and after) and preserves the compatibility.
DBMS_JOB.USER_EXPORT ( job IN BINARY_INTEGER, mycall IN OUT VARCHAR2); DBMS_JOB.USER_EXPORT ( job IN BINARY_INTEGER, mycall IN OUT VARCHAR2, myinst IN OUT VARCHAR2);