1. model a process which updates the same variable in different service tasks:
- ServiceTask1 creates variable "X" and set the value to 1
- ServiceTask2 updates variable "X" and set the value to 2
- ServiceTask3 updates variable "X" and set the value to 3
2. deploy this process to the engine
3. start a new instance of the deployed process
4. when the process instance finishes then have a look into db tables "ACT_HI_DETAIL" and "ACT_HI_VARINST"
--> the revision of variable "X" is 0 in "ACT_HI_VARINST", furthermore there exists for each update of the variable "X" an entry in "ACT_HI_DETAIL" and they all have also the revision 0
The variable update events can be ordered by its occurrence. Therefore a variable instance maintains a local sequence counter.