Problems with getting messages when using message grouping on z/OS

Use this topic to understand some of the issues with getting messages when using message grouping on IBM MQ for z/OS .

Is the application waiting for a complete group of messages?

Ensure all the messages in the group are on the queue. If we are using distributed queuing, see Problems with missing messages when using distributed queuing on z/OS. Ensure the last message in the group has the appropriate MsgFlags set in the message descriptor to indicate that it is the last message. Ensure the message expiry of the messages in the group is set to a long enough interval that they do not expire before they are retrieved.

If messages from the group have already been retrieved, and the get request is not in logical order, turn off the option to wait for a complete group when retrieving the other group messages.

If the application issues a get request in logical order for a complete group, and midway through retrieving the group it cannot find a message:

Ensure that no other applications are running against the queue and getting messages. Ensure that the message expiry of the messages in the group is set to a long enough interval that they do not expire before they are retrieved. Ensure that no one has issued the CLEAR QUEUE command. We can retrieve incomplete groups from a queue by getting the messages by group ID, without specifying the logical order option.

Parent topic: Dealing with incorrect output on z/OS