CA Aion BRE supports Suspend/Resume functionality for Aion components running in MAES. This allows the client program to suspend a component in MAES and free the APPC session, and then resume that component's activity at a later time using a new APPC session and continue processing. MAES keeps the component server task in a suspended state and keeps the component DLL loaded. All memory content remains available.
The Suspend/Resume functionality allows online client programs to access reusable ("hot") apps executing in MAES. There are two options for implementing hot apps:
While the performance of these two options is comparable, the MAES-managed option offers several advantages.
With client-managed hot apps, the online client is responsible for managing the hot apps. This requires a special client program (commonly a CICS PLT startup task) to start up whatever number of hot apps is desired (assuming a different task ID for each copy), SUSPEND each copy of the app, and save off the associated task IDs in a database table. Later, client programs access the database table to locate an available hot app task ID, update the table to reserve the app, assume the task ID of the available app, RESUME the app, use the app as desired, SUSPEND the app, and finally update the table to indicate that the app was once again available for reuse.Refer to <aionhlq>.SAMPLES.README(CLIENT) for example client programs, see the sample client programs ending in 2 .
With MAES-managed hot apps, MAES automatically initializes the desired number of hot apps and will dynamically start additional hot apps should the need arise. All the client program has to do is ACQUIRE the app, use the app as desired, and RELEASE the app. To have MAES automatically initialize hot apps, see the MAESPRLD DD statement in the section Specify MAES Runtime Parameters and DD Statements. Refer to <aionhlq>.SAMPLES.README(CLIENT) for example client programs, see the sample client programs ending in 3.
Important! CICS client programs using the RESUME and SUSPEND or ACQUIRE and RELEASE functions must ensure that the APPC conversation ID (EIBRSRCE, an 8-byte character field in the EIB), remains constant for all function calls between the RESUME and SUSPEND or ACQUIRE and RELEASE calls. The EIBRSRCE field contains the ID of the APPC conversation with MAES and is overridden by CICS with the conversation ID for the user's terminal. Unless a client program makes all its component calls between terminal SENDs, the EIBRSRCE value must be saved prior to each terminal I/O and restored afterwards. Otherwise, the next method call fails because the connection to MAES cannot be identified correctly.
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