Backout processing

Transaction updates can be backed out for a variety of reasons.

Transaction updates are backed out when any of the following occurs:
  • Backout is issued by the application program.
  • The application program terminates abnormally.
  • The application program terminates normally, but the implicit commit fails.
  • IMS resources are inflight during IMS system restart.
The backout consists of the following actions:
  • All database updates are backed out.
  • All messages inserted to non-express alternate PCBs are discarded.
  • All messages inserted to express PCBs that have not been enqueued are discarded.
  • The APPC/MVS™ verb ATBCMTP TYPE=ABEND is issued. 1

The application program tells IMS that a backout is required by issuing SRRBACK or by terminating abnormally.

1 Issuing the verb ATBCMTP causes all LU 6.2 conversations associated with this TPI to terminate with CM_DEALLOCATE_ABEND.