The heuristic end-transaction scenario

A heuristic end transaction is an independent action taken by the administrator to roll back a piece of work and remove all information about the transaction from the transaction table. The heuristic end-transaction process is initiated when the administrator executes the onmode -Z address command.

Whenever you initiate a heuristic end transaction by running onmode -Z, you remove critical information required by the database server to support the two-phase commit protocol and its automatic-recovery features. If you run onmode -Z, it becomes your responsibility to determine whether your networked database system is consistent.