What happens to queued events (Classic Event) when application node restarts?

ArjunBasnet
Tera Guru

‎06-17-2023 02:10 AM

This support article explains that scheduled jobs related transactions are terminated and queued for reprocessing when node restarts. 

https://support.servicenow.com/kb?id=kb_article_view&sysparm_article=KB0870543

The events queued in (sysevent.list) are processed via queue event processor, which are just a scheduler (sys_trigger record). Thus, one could assume that there will be similar consequences with event processing during application node restart.

 

Has anyone discovered, event being processed twice due to application node restart? How is event processing handled during application node restart?
 

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Ratnakar7
Mega Sage
Mega Sage

‎06-18-2023 09:35 AM

Hi @ArjunBasnet ,

 

The event processing during a restart is handled by the Event Queue Manager, which ensures that the queued events are processed correctly.

Here's how event processing is handled during an application node restart:

  1. When an application node restarts, the Event Queue Manager detects the restart and takes appropriate actions to handle the queued events.

  2. The Event Queue Manager maintains the state of the event processing and ensures that events are processed only once, even in the event of a restart.

  3. After the application node restarts, the Event Queue Manager resumes processing the queued events from where it left off before the restart.

  4. The queued events are processed in the order they were queued, ensuring that events are not missed or processed twice.

 

Thanks,

Ratnakar

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