# Tag Value Change Scripts: Are They Run Asynchronously?

**URL:** <https://forum.inductiveautomation.com/t/tag-value-change-scripts-are-they-run-asynchronously/53749>\
**Category:** Ignition\
**Tags:** ignition79, ignition81\
**Created:** [December 3, 2021, 7:12pm UTC](https://forum.inductiveautomation.com/t/tag-value-change-scripts-are-they-run-asynchronously/53749 "2021-12-03T19:12:57Z")\
**Posts on this page:** 1\
**Showing post:** 5

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**Author:** ![lrose](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/lrose/32/62724_2.png) [@lrose](https://forum.inductiveautomation.com/u/lrose)\
**Post date:** [December 3, 2021, 7:28pm UTC](https://forum.inductiveautomation.com/t/tag-value-change-scripts-are-they-run-asynchronously/53749/5 "2021-12-03T19:28:18Z")

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> [@Kevin.Herron](#):
>
> Each tag can have up to 5 pending executions queued

This seems contrary to this:

> [@Tag Change Missed Events](https://forum.inductiveautomation.com/t/tag-change-missed-events/37764/13):
>
> Another tag script performance piece that may be affecting OP is that there is a dedicated thread pool size 3 that all tag change scripts are executed on. So in addition to having a per-tag queue of size 5 that events will sit in, there’s only ever 3 tag change scripts executing at once. This is where you can really get into trouble with long running scripts (as @pturmel hinted), because if you have 3 long running scripts then nothing else is executing until at least one of them finishes.

Is it possible that if there are other tag change scripts running that you could miss one with out the flag being set? Or do I just not clearly understand how it works?

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