Managing IBM CICS LU 6.2 Transactions

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Applies To: Windows 10, Windows 7, Windows 8, Windows 8.1, Windows Server 2008, Windows Server 2008 R2, Windows Server 2012, Windows Server 2012 R2, Windows Server Technical Preview, Windows Vista

The DTC can participate in distributed transactions with IBM systems that support the IBM LU 6.2 protocol. If the connection between the Windows system and the IBM system fails and remains down, a transaction outcome can remain in doubt for an extended period of time. In this event, the IBM system may choose to heuristically commit or abort the transaction. Essentially, this means that the IBM system guesses the transaction's outcome rather than waiting to be told its outcome. Having heuristically committed or aborted the transaction, the IBM system can then release the locks held on behalf of the transaction. This allows other applications to access the records that were updated and locked by the transaction.

When the connection between the Windows system and the IBM system is restored, the DTC transaction manager compares the actual transaction outcome with the IBM system's heuristic decision about the transaction. The DTC reports the event in the application event log if the IBM system aborted the transaction or reported a heuristic mixed outcome when the DTC committed the transaction.

The DTC also reports the event in the application event log if the IBM system mistakenly aborted the transaction or reported a heuristic mixed outcome, or if the IBM system aborted the transaction or reported a heuristic mixed outcome when the DTC aborted the transaction.

See Also

Managing XA Transactions
Using the DTC Transaction List and Transaction Properties Windows