Retrieving ALTPCB output from a back-end IMS system

In a shared-queues environment, unless you take additional steps, the alternate PCB (ALTPCB) output placed on the shared queue by a back-end IMS system has affinity to the back-end system. This affinity prevents the originating front-end IMS system from retrieving the output unless you take additional steps.

To enable a front-end IMS system to retrieve ALTPCB output that is placed on the shared queue by a back-end IMS system, you can use the following solutions:

Procedure

  1. Enable the super member function and code the OTMA client to issue a resume tpipe call at the front-end IMS system.
    All retrieval options of the resume tpipe call are supported in the shared-queues environment.
  2. Disable the back-end affinity. This option is useful for OTMA clients that do not use the super member function, such as IBM® MQ.
    You can disable the back-end affinity by either of the following methods:
    • In the OTMA client descriptor in the DFSYDTx PROCLIB member of the front-end IMS system, specify ALTPCBE=YES.
    • In third byte of the state data prefix of the input transaction message, set the TMAMALTB flag (X'01').

    When either of these two options are specified, the ALTPCB output generated at the back-end IMS system is delivered to the front-end IMS via the shared queue.

  3. Enable the SENDALTP function for IMS Connect customers. By using this solution, an ALTPCB output is sent back to the initiating IMS Connect client without the need of a resume tpipe call.