26.3.7 MTA Messages are Not Delivered

In addition to message transport problems, there are two common problems which can result in unprocessed messages in the message queues:

1. The queue cache is not synchronized with the messages in the queue directories. Message files in the MTA queue subdirectories that are awaiting delivery are entered into an in-memory queue cache. When channel programs run, they consult this queue cache to determine which messages to deliver in their queues. There are circumstances where there are message files in the queue, but there is no corresponding queue cache entry.

   1. To check if a particular file is in the queue cache, you can use the imsimta cache -view utility; if the file is not in the queue cache, then the queue cache needs to be synchronized.

      The queue cache is normally synchronized every four hours. If required, you can manually resynchronize the cache by using the command imsimta cache -sync. Once synchronized, the channel programs will process the originally unprocessed messages after new messages are processed. If you want to change the default (4 hours), you should modify the job_controller.cnf file in directory msg-svr-base/config by adding sync_time=timeperiod where timeperiod reflects how often the queue cache is synchronized. Note that the timeperiod must be greater than 30 minutes. In the following example, the queue cache synchronization is modified to 2 hours by adding the sync_time=02:00 to the global defaults section of the job_controller.cnf:

      ! VERSION=5.0 !IMTA job controller configuration file ! !Global defaults tcp_port=27442 secret=N1Y9[HzQKW slave_command=NULL sync_time=02:00

      You can run imsimta submit channel to clear out the backlog of messages after running imsimta cache -sync. It is important to note that clearing out the channel may take a long time if the backlog of messages is large (greater than 1000).

      For summarized queue cache information, run imsimta qm -maint dir -database -total.

   2. If after synchronizing the queue cache, messages are still not being delivered, you should restart the Job Controller. To do so, use the imsimta restart job_controller command.

      Restarting the Job Controller will cause the message data structure to be rebuilt from the message queues on disk.

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      Caution –

      Restarting the Job Controller is a drastic step and should only be performed after all other avenues have been thoroughly exhausted.

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      Refer 8.7 The Job Controller for more information on the Job Controller.

2. Channel processing programs fail to run because they cannot create their processing log file. Check the access permissions, disk space and quotas.