with() declarations refresh on any user action regardless of connection

That is the expected behaviour in a with

This is expected. You can find more about with() here:
forum.appian.com/.../Evaluation_Functions.html

@marky To the best of my knowledge, a connection isn't required and the code present in with() evaluates for each and every user interaction (with a component that has saveInto, that is, editable) carried out anywhere in the entire interface. This is the expected behavior (and in fact the architecture) of SAIL.

If you can pick up an example from the documentation at https://forum.appian.com/suite/help/16.3/SAIL_Design.html#saving-input-into-variables under the section named 'with() and load()' you can observe that the variable named 'local!withVariable' refreshes upon interaction with 3rd and 4th(textField and button) components as they have 'saveInto'(or are editable).

yes, This is expected behavior of with() annotation.

This seems extremely wasteful, as things will be re-evaluated regardless of whether they should be re-evaluated, causing extra performance overhead on every single user action. We noticed that completely unrelated functionality was re-triggering query entities on every user interaction, which lead to our DB Connections hitting the limit during load tests. I guess I will try to get a support ticket opened to change this in a future release.

Yes, I agree with you Mark. Let me know if you get more details from the support ticket.

I think you will find this link helpful: forum.appian.com/.../SAIL_Performance.html

@Mark you can refactor your code to use load() variables instead of with() variables and target reevaluations for certain variables based on certain actions

That's a good description of the way things currently work, but I see lots of room for improvement: 1) with should not re-evaluate for unrelated things. 2) When an expression rule is called multiple times by apply, each instance of the expression rule should have its own unique load variables and not share load variables. 3) The entire interface should not being transmitted for small changes to the interface.

Mark, take a look at a!applyComponents. That should take care of number 2.
forum.appian.com/.../System_Functions.html