Hotfix for when the Triggers service seems to act randomly in MSMQ 3.0

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This KB:

937549 FIX: Random messages may not be processed, and duplicate messages may be processed by the trigger rule when you use the Message Queuing Triggers service to process messages in Message Queuing 3.0

is pretty irritating to me - there is so little content to help you understand what's going wrong:

In Microsoft Message Queuing 3.0, you use the Message Queuing Triggers service to process messages in a queue. Under a heavy workload, you may experience the following symptoms:

  • Random messages may not be processed and may remain in the queue.
  • Duplicate messages may be processed by the trigger rule.

This problem occurs because the Message Queuing Triggers service incorrectly skips a message.

It would be nice to understand why the service skipped a message as this knowledge may be useful in ensuring your own custom-written apps - and the Triggers service is effectively just another MSMQ-using app - don't have the same problem.

But, rant over, if you use the Triggers service under load then please regard the hotfix as a "Must Have".

Note - KB 937549 is a May 2007 update so is already included in this August 2007 hotfix:

941560 FIX: A general protection fault (GP fault) error occurs when you restart an outgoing queue in Microsoft Message Queuing 3.0