Transient workflows are often used for processing read-only requests or in cases where it is sufficient for the workflow processes to reside in the system main memory.
Persistent workflows are stored in the database. They are typically used in the following situations:
Workflow instances exist over a longer time period such as days, weeks, or even months. In such cases, the workflow instances must survive the starting and stopping of the application.
In case of a crash recovery, the affected workflow instances must be restored. To enable this, so-called checkpoints are written to the database.
COPPER runs in a distributed environment. Multiple copper engines, running on different nodes, are then coupled to a cluster. This offers high availability, load distribution and automatic failover in case that one or more nodes should crash. Please note that this feature requires a high availability database system, e.g. Oracle RAC.