Job Classes
Job classes allow the grouping of jobs with
similar characteristics and resource
requirements to ease administration.
If the
job_class
parameter of the
create_job
procedure is undefined, the job is assigned to a
job class called DEFAULT_JOB_CLASS.
Job classes are created using the
create_job_class procedure
listed below.
PROCEDURE create_job_class(
job_class_name
IN VARCHAR2,
resource_consumer_group IN VARCHAR2
DEFAULT NULL,
service
IN VARCHAR2
DEFAULT NULL,
logging_level
IN PLS_INTEGER
DEFAULT DBMS_SCHEDULER.LOGGING_RUNS,
log_history
IN PLS_INTEGER
DEFAULT NULL,
comments
IN VARCHAR2
DEFAULT NULL)
The parameters associated with this procedure
and their usage are as follows:
-
job_class_name
- A name that uniquely identifies the job
class
-
resource_consumer_group -
The resource consumer group associated with
the job class
-
service
- The service database object the job
belongs to, not the
tnsnames.ora service
-
logging_level
-
The amount of logging that should be done
for this job specified by the constants
logging_off,
logging_runs,
and
logging_full
-
log_history
- The number of days the logging information
is kept before purging
-
comments
- Free text allowing the user to record
additional information
Suffice it to say that it must be decided with
which resource consumer group the job class
should be associated.
Information about resource consumer
groups can be displayed using the
view.
select
consumer_group
from
dba_rsrc_consumer_groups
;
CONSUMER_GROUP
------------------------------
OTHER_GROUPS
DEFAULT_CONSUMER_GROUP
SYS_GROUP
LOW_GROUP
AUTO_TASK_CONSUMER_GROUP
With this information, a new job class can be
defined as follows:
BEGIN
DBMS_SCHEDULER.create_job_class (
job_class_name
=> 'test_job_class',
resource_consumer_group => 'default_consumer_group');
END;
/
Figure 11.21 shows the Create Job Class screen
in the OEM DB Control.
Figure 11.21 –
OEM DB Control: Create Job Class
Information about job classes can be displayed
using the
dba_scheduler_job_classes
view.
The following script uses this view:
select
job_class_name,
resource_consumer_group
from
dba_scheduler_job_classes
;
Here is the output from the
job_classes.sql
script:
JOB_CLASS_NAME
RESOURCE_CONSUMER_GROUP
------------------------------
------------------------------
DEFAULT_JOB_CLASS
AUTO_TASKS_JOB_CLASS
AUTO_TASK_CONSUMER_GROUP
TEST_JOB_CLASS
DEFAULT_CONSUMER_GROUP
3 rows selected.
Figure 11.22 shows the Scheduler Job Classes
screen in the OEM DB Control.
Figure 11.22 –
OEM DB Control: Scheduler Job Classes
Jobs can be assigned to a job class during
creation.
It is also possible to assign a job to an
alternative job class after creation using one
of the
set_attribute
procedure overloads.
BEGIN
-- Job defined and assigned to a job
class.
DBMS_SCHEDULER.create_job (
job_name
=> 'test_prog_sched_class_job_def',
program_name
=> 'test_plsql_block_prog',
schedule_name => 'test_hourly_schedule',
job_class
=> 'test_job_class',
enabled
=> TRUE,
comments
=> 'Job defined and assigned to a job
class ');
END;
/
BEGIN
-- Assign an existing job to a job
class.
DBMS_SCHEDULER.set_attribute (
name
=> 'test_prog_sched_job_definition',
attribute => 'job_class',
value
=> 'test_job_class');
END;
/
The output from the
jobs_10g.sql
script shows that the job classes associated
with these jobs have been set correctly.
OWNER
JOB_NAME
JOB_CLASS
ENABLE
----------
------------------------------ ----------------
------
NEXT_RUN_DATE
-----------------------------------------------------------------
REPEAT_INTERVAL
-----------------------------------------------------------------
JOB_USER
TEST_FULL_JOB_DEFINITION
DEFAULT_JOB_CLASS
TRUE
22-JUN-04 15.00.08.900000
+01:00
freq=hourly; byminute=0
JOB_USER
TEST_PROG_SCHED_JOB_DEFINITION
TEST_JOB_CLASS
TRUE
22-JUN-04 15.00.16.200000
+01:00
JOB_USER
TEST_PROG_JOB_DEFINITION
DEFAULT_JOB_CLASS
TRUE
22-JUN-04 15.00.09.600000
+01:00
freq=hourly; byminute=0
JOB_USER
TEST_SCHED_JOB_DEFINITION
DEFAULT_JOB_CLASS
TRUE
22-JUN-04 15.00.16.200000
+01:00
JOB_USER
ARGUMENT_JOB_DEFINITION
DEFAULT_JOB_CLASS
TRUE
22-JUN-04 15.00.16.200000
+01:00
JOB_USER
TEST_PROG_SCHED_CLASS_JOB_DEF
TEST_JOB_CLASS
TRUE
22-JUN-04 15.00.16.200000
+01:00
6 rows selected.
Job classes can be removed using the
drop_job_class
procedure listed below:
PROCEDURE drop_job_class (
job_class_name
IN VARCHAR2,
force
IN BOOLEAN DEFAULT FALSE)
The parameters associated with this procedure
and their usage are as follows:
-
job_class_name
- A name that specifies a single or comma
separated list of job class names
-
force
- When set to TRUE, all jobs that are
assigned to the job class are disabled and
have their job class set to the default.
When set to FALSE, attempting to drop
a job class that has dependent jobs will
cause an error.
The following code example shows how a job class
can be removed.
BEGIN
DBMS_SCHEDULER.drop_job_class (
job_class_name => 'test_job_class',
force
=> TRUE);
END;
/
The output of the
job_classes.sql
script shows that the job class has been removed
successfully.
JOB_CLASS_NAME
RESOURCE_CONSUMER_GROUP
------------------------------
------------------------------
DEFAULT_JOB_CLASS
AUTO_TASKS_JOB_CLASS
AUTO_TASK_CONSUMER_GROUP
2 rows selected.
Now that the creation of job classes has been
presented, the next section will cover windows,
which is another type of scheduler
administration object.
