Job System Health

Dispatching

Job Dispatchers are services that handle dispatching the Job Steps for execution. You can view the current status of all dispatchers in your Enterprise Manager environment as well as change the configuration from the Dispatchers dashboard.

Accessing the Dispatchers dashboard:

  1. From the Enterprise Manager Setup menu, select Manage the Manager and then Job System Console.
  2. After clicking Job System Health from the drop menu, select the Dispatching tab, or by clicking the Dispatching module in the Job System Health section of the Overview page.

    The Dispatching dashboard displays showing all dispatchers and their current service status, with four metrics at the top indicating status, count, type and maintenance mode of the dispatchers. The metrics can be used to quickly filter the dispatchers.

  3. Select a dispatcher from the list.
  4. Click Configuration to display all configurable parameters for the selected dispatcher.
  5. Modify the configuration settings as appropriate.

Configuring Dispatchers

From the Configuration tab, you can modify a dispatcher's configuration parameters. See Sizing Your Enterprise Manager Deployment for more information about optimizing Enterprise Manager configuration.

General

You can switch Maintenance Mode for the dispatcher on or off. When in Maintenance Mode all steps which are not system steps will fail. System steps are processed normally by the dispatcher.

Intervals

Sleep Interval

  • Sleep Interval Increment: Maximum number of seconds to sleep between each dispatcher sweep when dispatcher is unable to pick up any steps.
  • Dispatcher Cycle Interval (minimum): Minimum number of seconds to sleep between each dispatcher sweep (value infractions)

    Dispatcher Cycle Interval (maximum): Maximum number of seconds to sleep between each dispatcher sweep when dispatcher is unable to pick up any steps.

Steps Scheduler

  • Health Check Interval: Time in seconds to check for health of DBMS_SCHEDULER processes (step_dispatcher)
  • Step Scheduler Interval: The interval (in secs) with which the dispatcher should attempt to run the step scheduler. The step scheduler interval applies when the DBMS_SCHEDULER processes are not running or the dispatcher also needs to handle step scheduling.

Thread Pool

Thread pools provide a way to scope the resources used by the Job System. For example, the user short pool defaults to 25 threads. This allows each OMS to run up to 25 different user steps marked short running concurrently.

Job steps can be categorized into 5 broad categories:

  • User Short -- End user (short running)
  • User Long -- End user (long running)
  • System Normal—Steps run by system jobs
  • System Critical—Steps run by system jobs
  • Internal -- Steps created by the Job System for performing low-level actions like step time outs, grace period timeouts and bookkeeping steps.

Connection Pool (maximum number of connections allowed for the Dispatcher)

There are three categories of connections:

  • Job Worker--Worker threads of the Job System that execute particular steps.
  • Job Receiver—Pool of threads to accept asynchronous status and updates from the agent.
  • Job Dispatcher—Takes care of the dispatching the steps to various workers for execution.

If the Job Worker percent usage is high, then it means the dispatcher cannot dispatch to all the workers in a timely fashion. In this situation, there could be a resource problem, and the environment could probably benefit from more worker threads. However, do not go beyond doubling the size of the threads. If doubling the number of threads does not seem high enough, contact Oracle as it might be better to add an additional OMS.

Viewing High-Level Details

Click on the Details tab to view a list of all dispatchers. Selecting a dispatcher from the list graphically displays the total number of steps executed as well as the number of connections made at a specific point in time.

Scheduling

The Scheduling tab shows four information panels at the top:

  • Cycle Count By Status: shows the number of running, completed ans stuck cycles.
  • Last Cycle: shows when the last cycle was finished and its status.
  • Cycle Spikes: shows the maximum duration of spikes in milliseconds and the maximum number of row updates.
  • Next Cycle: when the next scheduled cycle will start and its status.

Bookkeeping

The Bookkeeping tab shows four information panels at the top:

  • Cycle Count By Status: shows the number of running, completed ans stuck cycles.
  • Last Cycle: shows when the last cycle was finished and its status.
  • Cycle Spikes: shows the maximum duration of spikes in milliseconds and the maximum number of row updates.
  • Next Cycle: when the next scheduled cycle will start and its status.

Purging

The Purging tab shows four information panels at the top:

  • Cycle Count By Status: shows the number of running, completed ans stuck cycles.
  • Last Cycle: shows when the last cycle was finished and its status.
  • Cycle Spikes: shows the maximum duration of spikes in milliseconds and the maximum number of row updates.
  • Next Cycle: when the next scheduled cycle will start and its status.