Process Engine icon on the Process Engines page is almost always grey or Process Engine stats don’t show

Management and Productivity IT-ROI Administrator
Posted @ 11/27/2012  11:05 AM By Glen Redden

NOTE: This issue only applies to Clarity 13.0 and above. It is a known bug that will be fixed in a future version of Clarity

DESCRIPTION:

Due to a change made to limit the amount of contention on the NMS_MESSAGES and NMS_MESSAGE_DELIVERY tables, the application services NMS Message Receiver threads no longer wake up when a multicast BPM event is sent. As a result, the process engine statistics and status become stale in the app UI.

TECHNICAL DETAILS:

The “Process Engines” page on the Administrative side of the UI is driven by a BPM event that provides process engine statistics back to the application. In 12.x and earlier, the application woke up to every multicast event. A previous bug fix removed the ability of the application to wake up to a BPM event and BPM events are only consumed at startup when messages fromNMS_MESSAGES are delivered to the app instance.

The one BPM event the app needs to receive is the process engine statistics message (OBJECT_CODE = ‘pe_monitor’ in NMS_MESSAGES). But because the thread never wakes up for a multicast event, these messages exist in NMS_MESSAGES but never get consumed by the app and because of this are not displayed on the Process Engines page.

STEPS TO REPLICATE:

1) launch a v13 app and bg instance (bg is process engine enabled)
2) Navigate in the app to “Process Engines” and wait a few minutes
3) Verify the status of the process engine and click the process engine name toget detailed statistics

EXPECTED RESULTS:

Status will be yellow indicating the PE is up and process engine statistics will be present

ACTUAL RESULTS:

Process engine status is grey and no statistics are available, yet rows existin NMS_MESSAGES for object_code = ‘pe_monitor’

WORKAROUND:

Modify the pipelines for the process engine (change any value) and hit
save. This will wake up the NMS Message Receiver thread in the app and you
will now see the status = yellow and updated statistics

1. Log into Clarity and go to the Process Engines page on the admin side
of Clarity.

2. Click on the name of the process engine that is not showing stats

3. Click on the Configure pipelines button

4. Make a change and click the submit button.

SUGGESTION:

When you click on Configure pipelines, change the Pre-Condition pipeline since this is the least used pipeline. I suggest, increasing it by one, saving the change and then changing it back to the original setting. Alternatively you could add one the first time you change it and subtract one the next time you change it so that you are hovering at close to the same number all of the time.