# Tag Change Missed Events

**URL:** <https://forum.inductiveautomation.com/t/tag-change-missed-events/37764>\
**Category:** Ignition\
**Created:** [August 15, 2020, 6:36pm UTC](https://forum.inductiveautomation.com/t/tag-change-missed-events/37764 "2020-08-15T18:36:41Z")\
**Posts on this page:** 5\
**Page:** 2

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**Author:** ![PRAMANJ](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/pramanj/32/66935_2.png) [@PRAMANJ](https://forum.inductiveautomation.com/u/PRAMANJ)\
**Post date:** [August 18, 2020, 3:53pm UTC](https://forum.inductiveautomation.com/t/tag-change-missed-events/37764/21 "2020-08-18T15:53:02Z")

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> [@pturmel](#):
>
> Go to project scripting, gateway events.

In fact I have been talking about these events only! So these events are not restricted to 3 threads and 5 event queues in each and there are no missed events! Is that correct? How does it work?

One more question I had on these event is how to register tags for these events thru scripts ? As I understand we can only register variables thru the scripting console. Is there a way to register tags thru scripts for these events?

(sorry for barging in this discussion, but it is interesting topic for me as well).

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**Author:** ![pturmel](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/pturmel/32/3295_2.png) [@pturmel](https://forum.inductiveautomation.com/u/pturmel)\
**Post date:** [August 18, 2020, 4:31pm UTC](https://forum.inductiveautomation.com/t/tag-change-missed-events/37764/22 "2020-08-18T16:31:00Z")

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> [@prafull\_j](#):
>
> Is there a way to register tags thru scripts for these events?

No.

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**Author:** ![pturmel](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/pturmel/32/3295_2.png) [@pturmel](https://forum.inductiveautomation.com/u/pturmel)\
**Post date:** [August 18, 2020, 4:32pm UTC](https://forum.inductiveautomation.com/t/tag-change-missed-events/37764/23 "2020-08-18T16:32:43Z")

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> [@jramirez3](#):
>
> how do i detect missed events?

As Kevin noted, there's no queued event limits for those, so short of a gateway out-of-memory error, they don't miss. (And Gateway OOM breaks so much throughout the server that a missed event would be the least of your worries.)

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**Author:** ![pturmel](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/pturmel/32/3295_2.png) [@pturmel](https://forum.inductiveautomation.com/u/pturmel)\
**Post date:** [August 18, 2020, 4:35pm UTC](https://forum.inductiveautomation.com/t/tag-change-missed-events/37764/24 "2020-08-18T16:35:51Z")

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Strictly speaking, project-based tag change events can miss when a project updates from a designer. You can tell that it updated, as scripting restarts and the event fires its “initialChange” again.

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**Author:** ![jsorlie](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/jsorlie/32/3645_2.png) [@jsorlie](https://forum.inductiveautomation.com/u/jsorlie)\
**Post date:** [March 16, 2021, 11:01pm UTC](https://forum.inductiveautomation.com/t/tag-change-missed-events/37764/25 "2021-03-16T23:01:00Z")

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I may be kind of late to the party but since no one mentioned using [system.util.invokeAsynchronous()](http://forum.inductiveautomation.com/t/system-util-invokeasynchronous/22057) to decouple data logging from the tag event queue. Even this approach will hit a wall if the transactional frequency is too “gregarious”.

@Kevin.Herron, @pturmel I would be curious to hear your thoughts.

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