System restart/resolve-in-doubt processing

After a system failure, a key part of restart processing is known as resolve-in-doubt processing. If the system fails, IMS determines whether to perform resolve-in-doubt processing for IMS-protected resources.

If the IMS system fails before the transaction completes phase one of the two-phase commit process (sync point), IMS backs out during IMS restart. Backout includes transactions that were processing at the time of failure.

If the transaction completes phase one of the commit process, resolve-in-doubt processing can take place during IMS restart. If only IMS resources are affected, commit processing occurs. If Db2 for z/OS resources are involved, resolve-in-doubt processing occurs between IMS and Db2 for z/OS.

No transactions using explicit CPI Communications driven application programs are preserved across an IMS restart.