Cold start

A Gateway daemon cold start option is provided to resolve heuristically-completed transactions. A heuristic error might occur after the failure of a transactional component, or manual intervention by an operator through the RRS panels.

In normal operation, the XA transaction manager component is responsible for issuing requests to "forget" transaction branches that have been heuristically resolved. If there is a heuristic error and the transaction manager is still running, it issues a "forget" call directly. However, if there is a heuristic error and the transaction manager is restarted before it has time to issue a "forget" call, the following happens:
In exceptional cases, the XA transaction manager might not have a record of a transaction branch being in "InForget" state, whereas RRS still has a record of the transaction branch being "InForget", "InCommit" or "InBackout" state. In this situation, the XA transaction manager does not issue an XA "forget" call, even if the Unit of Recovery (UR) is returned in response to an XA recover flow. This can happen: The Gateway daemon indicates the number of recovered URs during initialization by issuing message CTG8628I. If this number is greater than zero, review the outstanding URs through RRS and consider restarting the Gateway daemon using the cold start option to remove those URs in "InForget" state. If a cold start is not specified (normal start), CICS Transaction Gateway does not issue any forget calls and the URs remain visible in RRS.

URs in "InCommit" or in "InBackout" state have been resolved by a Gateway daemon in the HA group on behalf of another Gateway daemon, following a failure during two-phase commit processing. Such URs progress to "InForget" state, when the resolving Gateway daemon is shut down. These URs are cleared when the originating Gateway daemon performs a cold start. The statistic GD_LXACOMP indicates when a Gateway daemon has resolved XA transactions on behalf of another Gateway daemon in the HA group.


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Timestamp icon Last updated: Tuesday, 19 November 2013


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