What are the possible causes of a Timer Thread RTE when all of the timers content are poll-groups?
In this case serial polling is done and a condition is defined on the timer.
Normally the timer will move the poll-groups on the execution queue that is running in the protocol thread. In case executing the group would take too long I would expect a Protocol Thread RTE, not a Timer Thread RTE. So when can this occur?
As Jan states, a number of issues can cause this problem. It's very difficult to say in general what's causing this and is to be evaluated case by case. A number of issues that can occur:
- thread crashed
- triggers before are stuck (triggering QAction which never finishes)
- timer execution is stuck (add polling groups on the stack)
Stuck in this case can mean e.g. waiting on locks required for safe memory operations. These locks can be triggered by e.g. a user action which temporarily blocks the scheduling of the polling in some cases.