Schedule Misfire

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How to resolve a Schedule Misfire, and an Error in Event Viewer: System trigger misfire for type [DetectNotRespondingRobotsJob], job [####] when noticed?

Note: Take a backup of the config file before making the recommended changes.

The situation when Quartz becomes incapable of firing a given trigger is called misfire. Sometimes Quartz is not capable of running a scheduled job at the mentioned time. Below are some reasons for the same,

  • All worker threads get busy running other jobs (probably with higher priority)

  • Job triggered late for some reason but misfire event occurred before the job started

  • The scheduler itself is down.

Root Cause: Most probable reason can be a network glitch. But for scheduler down scenario, a more in depth investigation is required.

Resolution:
Make below changes to web.config(for v 2020.4.x or lower)/ UiPath.Orchestrator.dll.config(for v2020.10.x or higher) for cause 1 and 2 :

  1. If the issue is because of unavailability of worker threads, then Increase key="quartz.threadPool.threadCount" value to "15" by default it is set to 10. Be aware that number of worker threads depends on CPU and OS types
  2. Increase key="quartz.jobStore.misfireThreshold" value to "90000" by default it is 60000. It defines how late the trigger should be considered misfired
  3. After making the changes, restart the website from IIS.
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