If data cannot be exchanged between transaction branches because a communication error occurred between nodes, the synchronization point must be acquired on each node by executing a command. If the synchronization point is acquired on each node, one transaction branch in the global transaction may be committed and another may be rolled back. Acquiring the synchronization point on each node is called heuristic decision. During heuristic decision, a function returns with an error if the synchronization point of the global transaction is acquired from a UAP. One of the following values will be returned from a function due to heuristic determination:

• DCTRNER_HEURISTIC (00903): The results of heuristic determination did not match the results of the synchronization point of the global transaction.
• DCTRNER_HAZARD (00904): The results of the synchronization point of the transaction branch that was completed by the heuristic method are unknown.

The results of the synchronization point of the UAP, resource manager, or global transaction that caused the return value to arise can be checked by reading the contents of the message log file.