Establishing a Multi-Trans TP that is Always Available

Multi-trans scheduling is especially suitable for transaction programs that must always be available to handle inbound requests. To ensure that an initiator is always available to run a multi-trans TP, a system programmer can do the following:

  1. In the TP profile, assign the TP to a unique class
  2. In the TP profile JCL, set the TIME parameter to NOLIMIT to prevent the IEFUTL exit of SMF from receiving control and terminating the address space that the multi-trans TP is running in.

Note that if a multi-trans TP receives no inbound requests for five minutes, the multi-trans TP receives a return code of 8 or 28 from Get_Transaction. The multi-trans TP must either call the Get_Transaction service again to wait for more work to arrive (if the return code is 8) or end the multi-trans TP (if the return code is 28). For more information about these return codes, see z/OS MVS Programming: Writing Transaction Programs for APPC/MVS.

To end or replace such a multi-trans TP, a system programmer can:

  1. Set its TP profile inactive to prevent new inbound requests
  2. Allow processing of queued requests to finish
  3. Activate the TP profile of the new multi-trans TP.
Parent topic: Multi-Trans Processing