84 DBMS_JOB

The DBMS_JOB package schedules and manages jobs in the job queue.

Note:

The DBMS_JOB package has been superseded by the DBMS_SCHEDULER package.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 140, "DBMS_SCHEDULER" and "Moving from DBMS_JOB to DBMS_SCHEDULER" in Oracle Database Administrator's Guide.

This chapter contains the following topics:

Using DBMS_JOB
- Security Model
- Operational Notes
Summary of DBMS_JOB Subprograms

Security Model

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.

Operational Notes

Working with Oracle Real Application Clusters
Stopping a Job

Working with Oracle Real Application Clusters

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.

DBMS_JOB.SUBMIT

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 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);

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.

DBMS_JOB.INSTANCE

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.

DBMS_JOB.CHANGE

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.

DBMS_JOB.RUN

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);

Stopping a Job

Note that, once a job is started and running, there is no easy way to stop the job.

Summary of DBMS_JOB Subprograms

Table 84-1 DBMS_JOB Package Subprograms

Subprogram	Description
BROKEN Procedure	Disables job execution
CHANGE Procedure	Alters any of the user-definable parameters associated with a job
INSTANCE Procedure	Assigns a job to be run by a instance
INTERVAL Procedure	Alters the interval between executions for a specified job
NEXT_DATE Procedure	Alters the next execution time for a specified job
REMOVE Procedure	Removes specified job from the job queue
RUN Procedure	Forces a specified job to run
SUBMIT Procedure	Submits a new job to the job queue
USER_EXPORT Procedures	Re-creates a given job for export, or re-creates a given job for export with instance affinity
WHAT Procedure	Alters the job description for a specified job

BROKEN Procedure

This procedure sets the broken flag. Broken jobs are never run.

Syntax

DBMS_JOB.BROKEN ( 
   job       IN  BINARY_INTEGER,
   broken    IN  BOOLEAN,
   next_date IN  DATE DEFAULT SYSDATE);

Parameters

Table 84-2 BROKEN Procedure Parameters

Parameter	Description
`job`	System-assigned ID of the job being run. To find this ID, query the `JOB` column of the `USER_JOBS` or `DBA_JOBS` view.
`broken`	Sets the job as broken or not broken. `TRUE` sets it as broken; `FALSE` sets it as not broken.
`next_date`	Next date when the job will be run.

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.

Usage Notes

Your job will not be available for processing by the job queue in the background until it is committed.
If a job fails 16 times in a row, Oracle automatically sets it as broken and then stops trying to run it.

CHANGE Procedure

This procedure changes any of the fields a user can set in a job.

Syntax

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);

Parameters

Table 84-3 CHANGE Procedure Parameters

Parameter	Description
`job`	System-assigned ID of the job being run. To find this ID, query the `JOB` column of the `USER_JOBS` or `DBA_JOBS` view.
`what`	PL/SQL procedure to run.
`next_date`	Next date when the job will be run.
`interval`	Date function; evaluated immediately before the job starts running.
`instance`	When a job is submitted, specifies which instance can run the job. This defaults to `NULL`, which indicates that instance affinity is not changed.
`force`	If this is `FALSE`, then the specified instance (to which the instance number change) must be running. Otherwise, the routine raises an exception. If this is `TRUE`, then any positive integer is acceptable as the job instance.

Usage Notes

Your job will not be available for processing by the job queue in the background until it is committed.
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.

Example

BEGIN
   DBMS_JOB.CHANGE(14144, null, null, 'sysdate+3');
   COMMIT;
END;

INSTANCE Procedure

This procedure changes job instance affinity.

Syntax

DBMS_JOB.INSTANCE ( 
   job        IN BINARY_INTEGER,
   instance   IN BINARY_INTEGER,
   force      IN BOOLEAN DEFAULT FALSE);

Parameters

Table 84-4 INSTANCE Procedure Parameters

Parameter	Description
`job`	System-assigned ID of the job being run. To find this ID, query the `JOB` column of the `USER_JOBS` or `DBA_JOBS` view.
`instance`	When a job is submitted, a user can specify which instance can run the job.
`force`	If this is `TRUE`, then any positive integer is acceptable as the job instance. If this is `FALSE` (the default), then the specified instance must be running; otherwise the routine raises an exception.

Usage Notes

Your job will not be available for processing by the job queue in the background until it is committed.

INTERVAL Procedure

This procedure changes how often a job runs.

Syntax

DBMS_JOB.INTERVAL ( 
   job       IN  BINARY_INTEGER,
   interval  IN  VARCHAR2);

Parameters

Table 84-5 INTERVAL Procedure Parameters

Parameter	Description
`job`	System-assigned ID of the job being run. To find this ID, query the `JOB` column of the `USER_JOBS` or `DBA_JOBS` view.
`interval`	Date function, evaluated immediately before the job starts running.

Usage Notes

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.
Your job will not be available for processing by the job queue in the background until it is committed.

Interval	Description
`'sysdate + 7'`	Run once a week.
`'next_day(sysdate,''TUESDAY'')'`	Run once every Tuesday.
`'null'`	Run only once.

NEXT_DATE Procedure

This procedure changes when an existing job next runs.

Syntax

DBMS_JOB.NEXT_DATE ( 
   job       IN  BINARY_INTEGER,
   next_date IN  DATE);

Parameters

Table 84-6 NEXT_DATE Procedure Parameters

Parameter	Description
`job`	System-assigned ID of the job being run. To find this ID, query the `JOB` column of the `USER_JOBS` or `DBA_JOBS` view.
`next_date`	Date of the next refresh: it is when the job will be automatically run, assuming there are background processes attempting to run it.

Usage Notes

Your job will not be available for processing by the job queue in the background until it is committed.

REMOVE Procedure

This procedure removes an existing job from the job queue. This currently does not stop a running job.

Syntax

DBMS_JOB.REMOVE ( 
   job       IN  BINARY_INTEGER );

Parameters

Table 84-7 REMOVE Procedure Parameters

Parameter	Description
`job`	System-assigned ID of the job being run. To find this ID, query the `JOB` column of the `USER_JOBS` or `DBA_JOBS` view.

Usage Notes

Your job will not be available for processing by the job queue in the background until it is committed.

Example

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

RUN Procedure

This procedure runs job JOB now. It runs it even if it is broken.

Running the job recomputes next_date. See data dictionary view USER_JOBS or DBA_JOBS.

Syntax

DBMS_JOB.RUN ( 
   job       IN  BINARY_INTEGER,
   force     IN  BOOLEAN DEFAULT FALSE);

Parameters

Table 84-8 RUN Procedure Parameters

Parameter	Description
`job`	System-assigned ID of the job being run. To find this ID, query the `JOB` column of the `USER_JOBS` or `DBA_JOBS` view.
`force`	If this is `TRUE`, then instance affinity is irrelevant for running jobs in the foreground process. If this is `FALSE`, then the job can be run in the foreground only in the specified instance.

Example

EXECUTE DBMS_JOB.RUN(14144);

Caution:

This re-initializes the current session's packages.

Exceptions

An exception is raised if force is FALSE, and if the connected instance is the wrong one.

SUBMIT Procedure

This procedure submits a new job. It chooses the job from the sequence sys.jobseq.

Syntax

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);

Parameters

Table 84-9 SUBMIT Procedure Parameters

Parameter	Description
`job`	System-assigned ID of the job being run. To find this ID, query the `JOB` column of the `USER_JOBS` or `DBA_JOBS` view
`what`	PL/SQL text o the job to be run. This must be a valid PL/SQL statement or block of code. For example, to run a stored procedure `P`, you could pass the string `P`; (with the semi-colon) to this routine. The SQL that you submit in the `what` parameter is wrapped in the following PL/SQL block: DECLARE job BINARY_INTEGER := :job; next_date DATE := :mydate; broken BOOLEAN := FALSE; BEGIN WHAT :mydate := next_date; IF broken THEN :b := 1; ELSE :b := 0; END IF; END; Ensure that you include the `;` semi-colon with the statement.
`next_date`	Next date when the job will be run.
`interval`	Date function that calculates the next time to run the job. The default is `NULL`. This must evaluate to a either a future point in time or `NULL`.
`no_parse`	A flag. The default is `FALSE`. If this is set to `FALSE`, then Oracle parses the procedure associated with the job. If this is set to `TRUE`, then Oracle parses the procedure associated with the job the first time that the job is run. For example, if you want to submit a job before you have created the tables associated with the job, then set this to `TRUE`.
`instance`	When a job is submitted, specifies which instance can run the job.
`force`	If this is `TRUE`, then any positive integer is acceptable as the job instance. If this is `FALSE` (the default), then the specified instance must be running; otherwise the routine raises an exception.

Usage Notes

Your job will not be available for processing by the job queue in the background until it is committed.
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.

Example

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

USER_EXPORT Procedures

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.

Syntax

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);

Parameters

Table 84-10 USER_EXPORT Procedure Parameter

Parameter	Description
`job`	System-assigned ID of the job being run. To find this ID, query the `JOB` column of the `USER_JOBS` or `DBA_JOBS` view.
`mycall`	Text of a call to re-create the given job.
`myinst`	Text of a call to alter instance affinity.

WHAT Procedure

This procedure changes what an existing job does, and replaces its environment.

Syntax

DBMS_JOB.WHAT ( 
   job       IN  BINARY_INTEGER,
   what      IN  VARCHAR2);

Parameters

Table 84-11 WHAT Procedure Parameters

Parameter	Description
`job`	System-assigned ID of the job being run. To find this ID, query the `JOB` column of the `USER_JOBS` or `DBA_JOBS` view.
`what`	PL/SQL procedure to run.

Usage Notes

Your job will not be available for processing by the job queue in the background until it is committed.
Some legal values of what (assuming the routines exist) are:
- 'myproc(''10-JAN-82'', next_date, broken);'
- 'scott.emppackage.give_raise(''JENKINS'', 30000.00);'
- 'dbms_job.remove(job);'