Run Jobs One After Another

Question

I know this is possible, I'm not sure how to go about it using Oracle's Scheduler. I simply want to create a special "queue" that I can submit jobs to which will run one after another. After they run, then then are gone. There many be no jobs at anyone time, and then at other times I may submit 10 jobs to the queue. Currently when I submit jobs they all run parrallel, this is not what I want. I guess I don't understand why Oracle calls it a Job Queue when all my jobs run in parrallel and not in a queue as the name implies.
This is not say that I don't have other jobs which I would not want to send to this "queue". In other cases I would just want to submit the job and let it run right away and not wait on anything.
I'm currently using the DBMS_JOB package, which I'm pretty sure won't let me do what I want.
Any help would be greatly appreciated.
Thanks,
Joe

Answer 1

Here is and example that creates Resource Manager objects and
two job classes that will permit 1 and 3 jobs to
run in parallel. Note this will work in 11R1 and 10.2.4
Assumes user user scott/tiger exists.
--  Remove existing scheduler objects, jobs and classes
CONNECT /  as sysdba
BEGIN
   DBMS_SCHEDULER.DROP_JOB_CLASS(
      JOB_CLASS_NAME => 'JOBQ_WIDTH_1_CLASS'
END;
BEGIN
   DBMS_SCHEDULER.DROP_JOB_CLASS(
      JOB_CLASS_NAME => 'JOBQ_WIDTH_3_CLASS'
END;
BEGIN
  FOR I IN 1..30 LOOP
  BEGIN
    SYS.DBMS_SCHEDULER.DROP_JOB(JOB_NAME => 'SCOTT.SERIAL_' || I, FORCE=>TRUE);
  EXCEPTION WHEN OTHERS THEN NULL;
  END;
END LOOP;
END;
BEGIN
  FOR I IN 1..90 LOOP
  BEGIN
    SYS.DBMS_SCHEDULER.DROP_JOB(JOB_NAME => 'SCOTT.PAR3_' || I, FORCE=>TRUE);
  EXCEPTION WHEN OTHERS THEN NULL;
  END;
END LOOP;
END;
ALTER SYSTEM SET RESOURCE_MANAGER_PLAN='';
set echo on
--  Remove previously defined  resource plan, resource plan
--  directives, and resource consumer groups  for this test
BEGIN
    -- Prepare the pending area
    DBMS_RESOURCE_MANAGER.CLEAR_PENDING_AREA;
    DBMS_RESOURCE_MANAGER.CREATE_PENDING_AREA;
    -- Delete resource plan, its resource plan directives, and
    -- any associated resource groups
    DBMS_RESOURCE_MANAGER.DELETE_PLAN_CASCADE(
       plan => 'JOBQS_PLAN'
    -- Submit the changes
    DBMS_RESOURCE_MANAGER.VALIDATE_PENDING_AREA;
    DBMS_RESOURCE_MANAGER.SUBMIT_PENDING_AREA;
END;
-- Create resource manager objects
BEGIN
   DBMS_RESOURCE_MANAGER.CLEAR_PENDING_AREA();
   DBMS_RESOURCE_MANAGER.CREATE_PENDING_AREA();
   DBMS_RESOURCE_MANAGER.CREATE_CONSUMER_GROUP (
        CONSUMER_GROUP => 'JOBQ_WIDTH_1_GROUP',  
        COMMENT => 'Consumer group to force jobs to execute in serial'
   DBMS_RESOURCE_MANAGER.CREATE_CONSUMER_GROUP (
        CONSUMER_GROUP => 'JOBQ_WIDTH_3_GROUP',  
        COMMENT => 'Consumer group to allow jobs to run in parallel 3'
   DBMS_RESOURCE_MANAGER.SUBMIT_PENDING_AREA();
END;
BEGIN
   DBMS_RESOURCE_MANAGER.CLEAR_PENDING_AREA();
   DBMS_RESOURCE_MANAGER.CREATE_PENDING_AREA();
   DBMS_RESOURCE_MANAGER.CREATE_PLAN
      ('JOBQS_PLAN', 'PLAN TO SUPPORT JOBQS');
   DBMS_RESOURCE_MANAGER.CREATE_PLAN_DIRECTIVE(
      PLAN => 'JOBQS_PLAN',
      GROUP_OR_SUBPLAN => 'JOBQ_WIDTH_1_GROUP',
      COMMENT=>'Associates with job class JOBQ_WIDTH_1_CLASS',
      CPU_P1 => 25,
      PARALLEL_DEGREE_LIMIT_P1 => 1,
      ACTIVE_SESS_POOL_P1 =>1
   DBMS_RESOURCE_MANAGER.CREATE_PLAN_DIRECTIVE(
      PLAN => 'JOBQS_PLAN',
      GROUP_OR_SUBPLAN => 'JOBQ_WIDTH_3_GROUP',
      COMMENT=>'Associates with job class JOBQ_WIDTH_3_CLASS',
      CPU_P1 => 75,
      PARALLEL_DEGREE_LIMIT_P1 => 2,
      ACTIVE_SESS_POOL_P1 =>3
   DBMS_RESOURCE_MANAGER.CREATE_PLAN_DIRECTIVE(
      PLAN => 'JOBQS_PLAN',
      GROUP_OR_SUBPLAN => 'OTHER_GROUPS',
      CPU_P1 => 0,
      CPU_P2 => 100,
      COMMENT=>'Required'
   DBMS_RESOURCE_MANAGER.VALIDATE_PENDING_AREA();
   DBMS_RESOURCE_MANAGER.SUBMIT_PENDING_AREA();
END;
-- Create scheduler classes
BEGIN
   DBMS_SCHEDULER.CREATE_JOB_CLASS(
      JOB_CLASS_NAME => 'JOBQ_WIDTH_1_CLASS',
      LOGGING_LEVEL => DBMS_SCHEDULER.LOGGING_FULL,
      LOG_HISTORY => 5,
      RESOURCE_CONSUMER_GROUP => 'JOBQ_WIDTH_1_GROUP',
      COMMENTS => 'Force jobs to run in serial, through plan JOBQ_PLAN and group JOBQ_WIDTH_1_GROUP'
END;
BEGIN
   DBMS_SCHEDULER.CREATE_JOB_CLASS(
      JOB_CLASS_NAME => 'JOBQ_WIDTH_3_CLASS',
      LOGGING_LEVEL => DBMS_SCHEDULER.LOGGING_FULL,
      LOG_HISTORY => 5,
      RESOURCE_CONSUMER_GROUP => 'JOBQ_WIDTH_3_GROUP',
      COMMENTS => 'Allow up to 3 jobs in parallel, enforced by plan JOBQ_PLAN and group JOBQ_WIDTH_3_GROUP'
END;
connect / as sysdba
grant execute on jobq_width_1_class to scott;
grant execute on jobq_width_3_class to scott;
begin
  dbms_resource_manager_privs.grant_switch_consumer_group('scott','JOBQ_WIDTH_1_GROUP',false);
  dbms_resource_manager_privs.grant_switch_consumer_group('scott','JOBQ_WIDTH_3_GROUP',false);
end;
alter system set resource_manager_plan='';
connect scott/tiger
begin
  for i in 1..30 loop
  sys.dbms_scheduler.create_job(job_name => 'scott.serial_' || i,
      job_type=>'plsql_block', job_action=>'dbms_lock.sleep(2);',
      job_class=>'jobq_width_1_class',
      enabled=>true);
  end loop;
end;
begin
  for i in 1..90 loop
  sys.dbms_scheduler.create_job(job_name => 'scott.par3_' || i,
      job_type=>'plsql_block', job_action=>'dbms_lock.sleep(2);',
      job_class=>'jobq_width_3_class',
      enabled=>true);
  end loop;
end;
/-- The par3_90 job should finish about the same time as the serial_30 job since
-- we run 3 jobs in paralled and serial respectively.
-- check user_scheduler_job_run_details for after the test completed to verify.