Dequeuing messages, responses, and transactions

You can use the /DEQUEUE command with the PURGE or PURGE1 keyword to dequeue messages, responses, and transactions that are in error for a specific MSC link.

When you enter the /DEQUEUE MSNAME PURGE command, the Message Control/Error exit routine (DFSCMUX0) is called before the command executes. The exit routine protects you from inadvertently entering the command in error and potentially destroying a message, response, or transaction by dequeuing it before it reaches its destination. The exit routine can suppress the dequeue of a message.

The system programmer must be aware of each of:

  • The existence of the /DEQUEUE command, and the consequences of using it
  • The interaction of the /DEQUEUE command with the Message Control/Error exit routine

The MTO should be aware of each of these facts:

  • Your installation policy for using the /DEQUEUE command
  • The fact that any messages that are dequeued are destroyed
  • The /DEQUEUE command should be reserved for emergency use only, or as dictated by your site
Recommendations:
  • Only authorize the MTO to issue the /DEQUEUE command.
  • Establish installation-specific standards for using the /DEQUEUE command. Be sure to identify in advance and validate the scenarios where the MTO should use this command. Consider the /DEQUEUE command when coding the Message Control/Error exit routine.