On an active Messaging Gateway system, deleting large numbers of messages from the delivery queue via the command line mta-control utility may cause the mail server process to stop accepting and delivering messages until the service is restarted. While the mail server process is hung, the mta-control command also does not finish as expected.

Deleting large numbers of messages from the queue on a SMG system that is actively accepting and delivering messages can cause a deadlock in the scheduler. Accepting and delivering messages is waiting for the delete to complete and the delete is waiting on the acceptance or delivery of a message to complete.

This is not a common occurance and has only been observed on very active systems when upwards of 1000 messages are being deleted at a time.

This is a known issue and will be addressed with the SMG 10.6.5 release.

Remediation

1. Cancel the 'mta-control' command that is running by typing Control-C. If the 'mta-control' command cannot be cancelled or the command line session used to run it is no longer available, proceed to step two.
2. Restart the mail server process by running 'service mta restart' from the command line. (please see HOWTO126402 for details on the service command)