Triggered channels

If a triggered channel refuses to run, the possibility of in-doubt messages should be investigated as described above.

Another possibility is that the trigger control parameter on the transmission queue has been set to NOTRIGGER by the channel. This happens when:

After diagnosing and fixing the problem, you must start the channel manually.

An example of a situation where a triggered channel fails to start is as follows:

  1. A transmission queue is defined with a trigger type of FIRST.
  2. A message arrives on the transmission queue, and a trigger message is produced.
  3. The channel is started, but stops immediately because the communications to the remote system are not available.
  4. The remote system is made available.
  5. Another message arrives on the transmission queue.
  6. The second message does not increase the queue depth from zero to one, so no trigger message is produced (unless the channel is in RETRY state). If this happens, the channel must be started manually.

    On WebSphere MQ for z/OS, if the queue manager is stopped using MODE(FORCE) during channel initiator shutdown, it may be necessary to manually restart some channels after channel initiator restart.