# Help with Tag Expression

**URL:** <https://forum.inductiveautomation.com/t/help-with-tag-expression/93326>\
**Category:** Ignition\
**Tags:** ignition81, perspective\
**Created:** [July 17, 2024, 10:44am UTC](https://forum.inductiveautomation.com/t/help-with-tag-expression/93326 "2024-07-17T10:44:49Z")\
**Posts on this page:** 1\
**Showing post:** 12

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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:** [July 18, 2024, 12:44pm UTC](https://forum.inductiveautomation.com/t/help-with-tag-expression/93326/12 "2024-07-18T12:44:47Z")

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Expression bindings are **synchronous**. They **must** return a value when executed. The `tag()` expression function **stalls** when first called, waiting for a reply to its subscription request. If you scatter `tag()` expression functions through a bunch of bindings in a commonly-used view, you will have stalls on those views that are the sum of all the stalls in the bindings.

Tag bindings don't stall. They simply don't produce any property assignment at all until the subscription answers, and only produce future assignments when the subscription delivers changes.

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