If the process engine persists all state information in a shared database, the system can become robust enough to survive the failure of a process engine—another engine can simply pick up where the previous one left off. The downside of this approach is that the state of each process instance has to be persisted in a central database after each processing step. This could easily turn the database into a new performance bottleneck. As so often happens, the architect has to find the correct balance between performance, robustness, cost, and maintainability.
