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Oracle® Database Administrator's Guide
11g Release 1 (11.1)

B28310-04
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Examples of Using the Scheduler

This section discusses the following topics:

Examples of Creating Jobs

This section contains several examples of creating jobs. To create a job, you use the CREATE_JOB or the CREATE_JOBS procedures.

Example 28-1 Creating a Single Regular Job

The following statement creates a single regular job called my_job1 in the oe schema:

BEGIN
DBMS_SCHEDULER.CREATE_JOB (
   job_name             => 'oe.my_job1',
   job_type             => 'PLSQL_BLOCK',
   job_action           => 'BEGIN DBMS_STATS.GATHER_TABLE_STATS(''oe'',
                            ''sales''); END;',
   start_date           => '15-JUL-08 1.00.00AM US/Pacific',
   repeat_interval      => 'FREQ=DAILY', 
   end_date             => '15-SEP-08 1.00.00AM US/Pacific',
   enabled              =>  TRUE,
   comments             => 'Gather table statistics');
END;
/

This job gathers table statistics on the sales table. It will run for the first time on July 15th and then once a day until September 15. To verify that the job was created, issue the following statement:

SELECT JOB_NAME FROM DBA_SCHEDULER_JOBS WHERE JOB_NAME = 'MY_JOB1';

JOB_NAME
------------------------------
MY_JOB1

Example 28-2 Creating a Set of Lightweight Jobs in a Single Transaction

The following example creates a set of lightweight jobs in one transaction:

DECLARE
 newjob sys.job;
 newjobarr sys.job_array;
BEGIN
 -- To create a lightweight job, the program must be enabled.
 -- The program action must be a PL/SQL block or stored procedure.
 DBMS_SCHEDULER.ENABLE('PROG1');

 newjobarr := sys.job_array();
 newjobarr.extend(5);
 FOR i IN 1..5 LOOP
   newjob := sys.job(job_name => 'LWJOB' || to_char(i),
                     job_style => 'LIGHTWEIGHT',
                     job_template => 'PROG1',
                     repeat_interval => 'FREQ=MINUTELY;INTERVAL=3',
                     start_date => systimestamp + interval '10' second,
                     enabled => TRUE
                    );
   newjobarr(i) := newjob;
 end loop;

 DBMS_SCHEDULER.CREATE_JOBS(newjobarr, 'TRANSACTIONAL');
END;
/

See Also:

Oracle Database PL/SQL Packages and Types Reference for detailed information about the CREATE_JOB procedure and "Creating Jobs" for further information

Examples of Creating Job Classes

This section contains several examples of creating job classes. To create a job class, you use the CREATE_JOB_CLASS procedure.

Example 28-3 Creating a Job Class

The following statement creates a job class:

BEGIN
DBMS_SCHEDULER.CREATE_JOB_CLASS (
   job_class_name              =>  'my_class1',
   service                     =>  'my_service1', 
   comments                    =>  'This is my first job class');
END;
/

This creates my_class1 in SYS. It uses a service called my_service1. To verify that the job class was created, issue the following statement:

SELECT JOB_CLASS_NAME FROM DBA_SCHEDULER_JOB_CLASSES
WHERE JOB_CLASS_NAME = 'MY_CLASS1';

JOB_CLASS_NAME
------------------------------
MY_CLASS1

Example 28-4 Creating a Job Class

The following statement creates a job class:

BEGIN
DBMS_SCHEDULER.CREATE_JOB_CLASS (
   job_class_name             =>  'finance_jobs', 
   resource_consumer_group    =>  'finance_group',
   service                    =>  'accounting',
   comments                   =>  'All finance jobs');
END;
/

This creates finance_jobs in SYS. It assigns a resource consumer group called finance_group, and designates service affinity for the accounting service. Note that if the accounting service is mapped to a resource consumer group other than finance_group, jobs in this class run under the finance_group consumer group, because the resource_consumer_group attribute takes precedence.

See Also:

Oracle Database PL/SQL Packages and Types Reference for detailed information about the CREATE_JOB_CLASS procedure and "Creating Job Classes" for further information

Examples of Creating Programs

This section contains several examples of creating programs. To create a program, you use the CREATE_PROGRAM procedure.

Example 28-5 Creating a Program

The following statement creates a program in the oe schema:

BEGIN
DBMS_SCHEDULER.CREATE_PROGRAM (
   program_name          => 'oe.my_program1',
   program_type          => 'PLSQL_BLOCK',
   program_action        => 'BEGIN DBMS_STATS.GATHER_TABLE_STATS(''oe'',
                             ''sales''); END;',
   number_of_arguments   => 0,
   enabled               => TRUE,
   comments              => 'My comments here');
END;
/

This creates my_program1, which uses PL/SQL to gather table statistics on the sales table. To verify that the program was created, issue the following statement:

SELECT PROGRAM_NAME FROM DBA_SCHEDULER_PROGRAMS 
WHERE PROGRAM_NAME = 'MY_PROGRAM1';

PROGRAM_NAME
-------------------------
MY_PROGRAM1

Example 28-6 Creating a Program

The following statement creates a program in the oe schema:

BEGIN
DBMS_SCHEDULER.CREATE_PROGRAM (
   program_name           => 'oe.my_saved_program1',
   program_action         => '/usr/local/bin/date',
   program_type           => 'EXECUTABLE',
   comments               => 'My comments here');
END;
/

This creates my_saved_program1, which uses an executable.

See Also:

Oracle Database PL/SQL Packages and Types Reference for detailed information about the CREATE_PROGRAM procedure and "Creating Programs" for further information

Examples of Creating Windows

This section contains several examples of creating windows. To create a window, you use the CREATE_WINDOW procedure.

Example 28-7 Creating a Window

The following statement creates a window called my_window1 in SYS:

BEGIN
DBMS_SCHEDULER.CREATE_WINDOW (
   window_name          =>  'my_window1',
   resource_plan        =>  'my_res_plan1',
   start_date           =>  '15-JUL-03 1.00.00AM US/Pacific',
   repeat_interval      =>  'FREQ=DAILY',
   end_date             =>  '15-SEP-03 1.00.00AM US/Pacific',
   duration             =>  interval '80' MINUTE,
   comments             =>  'This is my first window');
END;
/

This window will open once a day at 1AM for 80 minutes every day from May 15th to October 15th. To verify that the window was created, issue the following statement:

SELECT WINDOW_NAME FROM DBA_SCHEDULER_WINDOWS WHERE WINDOW_NAME = 'MY_WINDOW1';

WINDOW_NAME
------------------------------
MY_WINDOW1

Example 28-8 Creating a Window

The following statement creates a window called my_window2 in SYS:

BEGIN
DBMS_SCHEDULER.CREATE_WINDOW ( 
   window_name       => 'my_window2',
   schedule_name     => 'my_stats_schedule',
   resource_plan     => 'my_resourceplan1',
   duration          => interval '60' minute,
   comments          => 'My window');
END; 
/

See Also:

Oracle Database PL/SQL Packages and Types Reference for detailed information about the CREATE_WINDOW procedure and "Creating Windows" for further information

Example of Creating Window Groups

This section contains an example of creating a window group. To create a window group, you use the CREATE_WINDOW_GROUP procedure.

Example 28-9 Creating a Window Group

The following statement creates a window group called my_window_group1:

BEGIN
DBMS_SCHEDULER.CREATE_WINDOW_GROUP ('my_windowgroup1');
END;
/

Then, you could add three windows (my_window1, my_window2, and my_window3) to my_window_group1 by issuing the following statements:

BEGIN
DBMS_SCHEDULER.ADD_WINDOW_GROUP_MEMBER (
   group_name   =>  'my_window_group1',
   window_list  =>  'my_window1, my_window2');

DBMS_SCHEDULER.ADD_WINDOW_GROUP_MEMBER (
   group_name   =>  'my_window_group1',
   window_list  =>  'my_window3');
END;
/

To verify that the window group was created and the windows added to it, issue the following statement:

SELECT * FROM DBA_SCHEDULER_WINDOW_GROUPS;

WINDOW_GROUP_NAME    ENABLED   NUMBER_OF_WINDOWS   COMMENTS
-----------------    -------   -----------------   ---------------
MY_WINDOW_GROUP1     TRUE                      3   This is my first window group

See Also:

Oracle Database PL/SQL Packages and Types Reference for detailed information about the CREATE_WINDOW_GROUP and ADD_WINDOW_GROUP_MEMBER procedures and "Creating Window Groups" for further information

Examples of Setting Attributes

This section contains several examples of setting attributes. To set attributes, you use SET_ATTRIBUTE and SET_SCHEDULER_ATTRIBUTE procedures.

Example 28-10 Setting the Repeat Interval Attribute

The following example resets the frequency my_emp_job1 will run to daily:

BEGIN
DBMS_SCHEDULER.SET_ATTRIBUTE (
   name           =>   'my_emp_job1',
   attribute      =>   'repeat_interval',
   value          =>   'FREQ=DAILY');
END;
/

To verify the change, issue the following statement:

SELECT JOB_NAME, REPEAT_INTERVAL FROM DBA_SCHEDULER_JOBS
WHERE JOB_NAME =  'MY_EMP_JOB1';

JOB_NAME             REPEAT_INTERVAL
----------------     ---------------
MY_EMP_JOB1          FREQ=DAILY

Example 28-11 Setting the Comments Attribute

The following example resets the comments for my_saved_program1:

BEGIN
DBMS_SCHEDULER.SET_ATTRIBUTE (
   name           =>   'my_saved_program1',
   attribute      =>   'comments',
   value          =>   'For nightly table stats');
END;
/

To verify the change, issue the following statement:

SELECT PROGRAM_NAME, COMMENTS FROM DBA_SCHEDULER_PROGRAMS;

PROGRAM_NAME        COMMENTS
------------        -----------------------
MY_PROGRAM1         My comments here
MY_SAVED_PROGRAM1   For nightly table stats

Example 28-12 Setting the Duration Attribute

The following example resets the duration of my_window3 to 90 minutes:

BEGIN
DBMS_SCHEDULER.SET_ATTRIBUTE (
   name           =>   'my_window3',
   attribute      =>   'duration',
   value          =>   interval '90' minute);
END;
/

To verify the change, issue the following statement:

SELECT WINDOW_NAME, DURATION FROM DBA_SCHEDULER_WINDOWS
WHERE WINDOW_NAME = 'MY_WINDOW3';

WINDOW_NAME        DURATION
-----------        ---------------
MY_WINDOW3         +000 00:90:00

Example 28-13 Setting the Database Role Attribute

The following example sets the database role of the job my_job to LOGICAL STANDBY.

BEGIN
DBMS_SCHEDULER.SET_ATTRIBUTE (
   name        => 'my_job',
   attribute   => 'database_role',
   value       =>'LOGICAL STANDBY');
END;
/

To verify the change in database role, issue the following command:

SELECT JOB_NAME, DATABASE_ROLE FROM DBA_SCHEDULER_JOB_ROLES
    WHERE JOB_NAME = 'MY_JOB';

JOB_NAME             DATABASE_ROLE
--------             -----------------
MY_JOB               LOGICAL STANDBY

Example 28-14 Setting the Event Expiration Attribute

The following example sets the time in seconds to 3600 when an event expires:

BEGIN
DBMS_SCHEDULER.SET_SCHEDULER_ATTRIBUTE (
   attribute     =>   event_expiry_time,
   value         =>   3600);
END;
/

Example 28-15 Setting Multiple Job Attributes for a Set of Jobs

The following example sets four different attributes for each of five jobs:

DECLARE
 newattr sys.jobattr;
 newattrarr sys.jobattr_array;
 j number;
BEGIN
 -- Create new JOBATTR array
 newattrarr := sys.jobattr_array();

 -- Allocate enough space in the array
 newattrarr.extend(20);
 j := 1;
 FOR i IN 1..5 LOOP
   -- Create and initialize a JOBATTR object type
   newattr := sys.jobattr(job_name => 'TESTJOB' || to_char(i),
                          attr_name => 'MAX_FAILURES',
                          attr_value => 5);
   -- Add it to the array.
   newattrarr(j) := newattr;
   j := j + 1;
   newattr := sys.jobattr(job_name => 'TESTJOB' || to_char(i),
                          attr_name => 'COMMENTS',
                          attr_value => 'Test job');
   newattrarr(j) := newattr;
   j := j + 1;
   newattr := sys.jobattr(job_name => 'TESTJOB' || to_char(i),
                          attr_name => 'END_DATE',
                          attr_value => systimestamp + interval '24' hour);
   newattrarr(j) := newattr;
   j := j + 1;
   newattr := sys.jobattr(job_name => 'TESTJOB' || to_char(i),
                          attr_name => 'SCHEDULE_LIMIT',
                          attr_value => interval '1' hour);
   newattrarr(j) := newattr;
   j := j + 1;
 END LOOP;

 -- Call SET_JOB_ATTRIBUTES to set all 20 set attributes in one transaction
 DBMS_SCHEDULER.SET_JOB_ATTRIBUTES(newattrarr, 'TRANSACTIONAL');
END;
/

See Also:

Oracle Database PL/SQL Packages and Types Reference for detailed information about the SET_SCHEDULER_ATTRIBUTE procedure and "Task 2E: Setting Scheduler Attributes"

Examples of Creating Chains

This section contains examples of creating chains. To create chains, you use the CREATE_CHAIN procedure. After creating a chain, you add steps to the chain with the DEFINE_CHAIN_STEP or DEFINE_CHAIN_EVENT_STEP procedures and define the rules with the DEFINE_CHAIN_RULE procedure.

Example 28-16 Creating a Chain

The following example creates a chain where my_program1 runs before my_program2 and my_program3. my_program2 and my_program3 run in parallel after my_program1 has completed.

The user for this example must have the CREATE EVALUATION CONTEXT, CREATE RULE, and CREATE RULE SET privileges. See "Setting Chain Privileges" for more information.

BEGIN
DBMS_SCHEDULER.CREATE_CHAIN (
   chain_name            =>  'my_chain1',
   rule_set_name         =>  NULL,
   evaluation_interval   =>  NULL,
   comments              =>  NULL);
END;
/
 
--- define three steps for this chain. Referenced programs must be enabled.
BEGIN
DBMS_SCHEDULER.DEFINE_CHAIN_STEP('my_chain1', 'stepA', 'my_program1');
DBMS_SCHEDULER.DEFINE_CHAIN_STEP('my_chain1', 'stepB', 'my_program2');
DBMS_SCHEDULER.DEFINE_CHAIN_STEP('my_chain1', 'stepC', 'my_program3');
END;
/

--- define corresponding rules for the chain.
BEGIN
DBMS_SCHEDULER.DEFINE_CHAIN_RULE('my_chain1', 'TRUE', 'START stepA');
DBMS_SCHEDULER.DEFINE_CHAIN_RULE (
   'my_chain1', 'stepA COMPLETED', 'Start stepB, stepC');
DBMS_SCHEDULER.DEFINE_CHAIN_RULE (
   'my_chain1', 'stepB COMPLETED AND stepC COMPLETED', 'END');
END;
/

--- enable the chain
BEGIN
  DBMS_SCHEDULER.ENABLE('my_chain1');
END;
/

--- create a chain job to start the chain daily at 1:00 p.m.
BEGIN
DBMS_SCHEDULER.CREATE_JOB (
   job_name        => 'chain_job_1',
   job_type        => 'CHAIN',
   job_action      => 'my_chain1',
   repeat_interval => 'freq=daily;byhour=13;byminute=0;bysecond=0',
   enabled         => TRUE);
END;
/

Example 28-17 Creating a Chain

The following example creates a chain where first my_program1 runs. If it succeeds, my_program2 runs; otherwise, my_program3 runs.

BEGIN
DBMS_SCHEDULER.CREATE_CHAIN (
   chain_name            => 'my_chain2',
   rule_set_name         => NULL,
   evaluation_interval   => NULL,
   comments              => NULL);
END;
/
 
--- define three steps for this chain.
BEGIN
DBMS_SCHEDULER.DEFINE_CHAIN_STEP('my_chain2', 'step1', 'my_program1');
DBMS_SCHEDULER.DEFINE_CHAIN_STEP('my_chain2', 'step2', 'my_program2');
DBMS_SCHEDULER.DEFINE_CHAIN_STEP('my_chain2', 'step3', 'my_program3');
END;
/
 
--- define corresponding rules for the chain.
BEGIN
DBMS_SCHEDULER.DEFINE_CHAIN_RULE ('my_chain2', 'TRUE', 'START step1');
DBMS_SCHEDULER.DEFINE_CHAIN_RULE (
   'my_chain2', 'step1 SUCCEEDED', 'Start step2');
DBMS_SCHEDULER.DEFINE_CHAIN_RULE (
   'my_chain2', 'step1 COMPLETED AND step1 NOT SUCCEEDED', 'Start step3');
DBMS_SCHEDULER.DEFINE_CHAIN_RULE (
   'my_chain2', 'step2 COMPLETED OR step3 COMPLETED', 'END');
END;
/

See Also:

Oracle Database PL/SQL Packages and Types Reference for detailed information about the CREATE_CHAIN, DEFINE_CHAIN_STEP, and DEFINE_CHAIN_RULE procedures and "Task 2E: Setting Scheduler Attributes"

Examples of Creating Jobs and Schedules Based on Events

This section contains examples of creating event-based jobs and event schedules. To create event-based jobs, you use the CREATE_JOB procedure. To create event-based schedules, you use the CREATE_EVENT_SCHEDULE procedure.

These examples assume the existence of an application that, when it detects the arrival of a file on a system, enqueues an event onto the queue my_events_q.

Example 28-18 Creating an Event-Based Schedule

The following example illustrates creating a schedule that can be used to start a job whenever the Scheduler receives an event indicating that a file arrived on the system before 9AM:

BEGIN
DBMS_SCHEDULER.CREATE_EVENT_SCHEDULE (
   schedule_name     =>  'scott.file_arrival',
   start_date        =>  systimestamp,
   event_condition   =>  'tab.user_data.object_owner = ''SCOTT'' 
      and tab.user_data.event_name = ''FILE_ARRIVAL'' 
      and extract hour from tab.user_data.event_timestamp < 9',
   queue_spec        =>  'my_events_q');
END;
/

Example 28-19 Creating an Event-Based Job

The following example creates a job that starts when the Scheduler receives an event indicating that a file arrived on the system:

BEGIN
DBMS_SCHEDULER.CREATE_JOB (
   job_name            =>  my_job,
   program_name        =>  my_program,
   start_date          =>  '15-JUL-04 1.00.00AM US/Pacific',
   event_condition     =>  'tab.user_data.event_name = ''FILE_ARRIVAL''',
   queue_spec          =>  'my_events_q'
   enabled             =>  TRUE,
   comments            =>  'my event-based job');
END;
/

See Also:

Oracle Database PL/SQL Packages and Types Reference for detailed information about the CREATE_JOB and CREATE_EVENT_SCHEDULE procedures

Example of Creating a Job In an Oracle Data Guard Environment

In an Oracle Data Guard environment, the Scheduler includes additional support for two database roles: primary and logical standby. You can configure a job to run only when the database is in the primary role or only when the database is in the logical standby role. To do so, you set the database_role attribute. This example explains how to enable a job to run in both database roles. The method used is to create two copies of the job and assign a different database_role attribute to each.

By default, a job runs when the database is in the role that it was in when the job was created. You can run the same job in both roles using the following steps:

  1. Copy the job

  2. Enable the new job

  3. Change the database_role attribute of the new job to the required role

The example starts by creating a job called primary_job on the primary database. It then makes a copy of this job and sets its database_role attribute to 'LOGICAL STANDBY'. If the primary database then becomes a logical standby, the job continues to run according to its schedule.

When you copy a job, the new job is disabled, so you must enable the new job.

BEGINDBMS_SCHEDULER.CREATE_JOB (
     job_name       => 'primary_job',
     program_name   => 'my_prog',
     schedule_name  => 'my_sched');

DBMS_SCHEDULER.COPY_JOB('primary_job','standby_job');
DBMS_SCHEDULER.ENABLE(name=>'standby_job', commit_semantics=>'ABSORB_ERRORS');
DBMS_SCHEDULER.SET_ATTRIBUTE('standby_job','database_role','LOGICAL STANDBY');
END;
/

After you execute this example, the data in the DBA_SCHEDULER_JOB_ROLES view is as follows:

SELECT JOB_NAME, DATABASE_ROLE FROM DBA_SCHEDULER_JOB_ROLES
   WHERE JOB_NAME IN ('PRIMARY_JOB','STANDBY_JOB');

JOB_NAME               DATABASE_ROLE
--------               ----------------
PRIMARY_JOB            PRIMARY
STABDBY_JOB            LOGICAL STANDBY

Note:

For a physical standby database, any changes made to Scheduler objects or any database changes made by Scheduler jobs on the primary database are applied to the physical standby like any other database changes.