We are having a problem and we'd like to understand a bit how Activiti's Engine works. Let assume the following flow example:
start -> ServiceTask1 -> ServiceTask2 -> end
Both ServiceTasks are async
Both ServiceTasks has a Listener when each of them starts.
Both Listeners update a row in one of our business tables.
The problem is that we are having Optimistic Lock errors because it seems that both listeners are trying to update the same row at the same time.
We guess that what is happening is:
The ServiceTask doesn't wait for the start Listener to finish
So ServiceTask1 finishes before its start Listener finishes and the start Listener of ServiceTask2 reads the db row before the Listener of ServiceTask1 writes the update
ServiceTask1's Listener writes the update
When ServiceTask2's Listener wants to write the update, the version is different so it throws an optimistic lock.
So, the questions we need to answer are:
Is this how ServiceTask's Listeners works or are we missing something?
Is there any way to make ServiceTasks to wait for the start Listener?
