Critical section is used to sync process instances so that only once process instance executes the grouped activities at any given time. Any concurrently running process instances that contain a corresponding critical section group wait until the process instance that is CURRENTLY executing the critical section group completes. Particularly used for controlling access to shared variables. Critical section is one of the group actions. Others are iterating, repeat until true, repeat on error until true, while true, pick FIRST and transaction. If we select critical section as the group, then we get two options. Single group and multiple groups.

Single Group

If you wish to synchronize process instances for a single process definition in a single process engine (only one ear(instance) is deployed), perform the following:

1. Create a group around the activities you wish to synchronize.
2. Specify Critical Section for the Group Action field.
3. Specify Single Group for the Scope field.
4. Only one process instance at any given time will execute the activities contained in the Critical Section group.

Multiple Groups:

If you wish to synchronize process instances for multiple process definitions, or if you wish to synchronize process instances across multiple process engines, perform the following:

• Create a Lock shared configuration resource and specify a name for the resource.
• To perform the synchronization across multiple process engines, CHECK the Multi-Engine field of the Lock resource. When the process instances are EXECUTED by the same process engine, locking is performed in memory. When the process instances are executed across multiple engines, the process engines must be configured to use a database for STORAGE, and a database transaction is performed to ensure that only one process instance is executing the critical section group at any given time.
• Create a group around the activities you wish to synchronize.
• Specify Critical Section for the Group Action Field.
• Specify Multiple Groups for the Scope field.
• Use the Browse button in the Lock Object field to locate the Lock shared configuration resource you created in Step 1.
• Perform steps 3 to 6 for any process definitions you wish to synchronize. Make sure you specify the same Lock shared configuration object for all Critical Section groups.

Critical section is used to sync process instances so that only once process instance executes the grouped activities at any given time. Any concurrently running process instances that contain a corresponding critical section group wait until the process instance that is currently executing the critical section group completes. Particularly used for controlling access to shared variables. Critical section is one of the group actions. Others are iterating, repeat until true, repeat on error until true, while true, pick first and transaction. If we select critical section as the group, then we get two options. Single group and multiple groups.

Single Group

If you wish to synchronize process instances for a single process definition in a single process engine (only one ear(instance) is deployed), perform the following:

Multiple Groups:

If you wish to synchronize process instances for multiple process definitions, or if you wish to synchronize process instances across multiple process engines, perform the following: