PRPT combo box with EXEC VARA data source — what determines when the executable object is executed?

Discussion created by Michael_Lowry on Feb 13, 2018
I recently posted an example workflow showing how to load prompt set default values from last-used values. During the course of testing this workflow, I noticed something that surprised me: when a PRPT combo box has an EXEC VARA data source, the executable object referenced by that VARA is not executed every time the combo box is activated. In this example, the EXEC VARA simply runs an SCRI that reads values from a static VARA. If I change the contents of the static VARA that is the ultimate source of the data, these changes are reflected in the combo box. So it’s not just using a static cache of the data retrieved from the initial execution. However, I was unable to find executions of the object that correspond to repopulating the combo box menu. Is the Automation Engine doing some clever trickery here, caching actions and re-running them internally without spawning new tasks?

In this case, all of the data required to repopulate the combo box menu are internal to the AE. But the executable object could be a JOBS object that accesses an external system. E.g., it could be a UNIX job or an SQL job. In those cases, it would be impossible for the AE to handle the task of repopulating the combo box menu using internal operations only. Perhaps in such cases I would see a new task spawned for each activation of the combo box.

For what it’s worth, the combo box I added to save currently-selected values does cause a task to be spawned each time it is activated. The only difference I can see is that this EXEC VARA points to an SCRI that actually makes changes.