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Description

Symptoms


  • Flow Designer is not executing as expected

Release


London Patch 2

Cause


The user had 2,800 events pending which made it look as though Flow designer Action "Aperture Science TCIAL" was not working. In actuality, the events needed to process the above Action were created successfully.

Rather, the real issue was that the event queue was backed up which prevented the processing of the event, and thus the execution of the Action.

Resolution


When an Action is fired in Flow designer (like "Aperture Science TCIAL"), it creates an event to execute that job. The "flow.start" events get processed by the "Flow Engine Event Handler" job in the sys_trigger table.

The problem is that while there were four of these "Flow Engine Event Handler" jobs in sys_trigger, all of them were in a state of "queued". They needed to instead be in a state of "ready". When the state of one of them was manually updated to "ready", the system immediately picked up the "flow.start" events and started processing them.

The entire back-log of events is now clear, and it did not take much time at all. The issue, the why and how of this blockage, was due to the state being in "queued" rather than in "ready".

After the back-up was cleared, a secondary test was run to ensure that everything worked as expected - and it did. The "Aperture Science TCIAL" Action processed perfectly.

Article Information

Last Updated:2019-08-02 20:56:22
Published:2018-12-31