Message Body MQDLH Buffer

(Optional) The MQDLH structure describes the information that is prefixed to the application message data of messages when they are on a dead letter queue.

It is recommended you use the default DLH message format but you can copy and alter as needed. Message formats using different message buffer types (MQMD, MQDLH, MQRFH2, MQXQH, MQIIH, Body, etc.) can reside in separate message formats and do not need to be combined. This allows common usage across activities for messages sent or received by a regular application, channel or end up on the dead letter queue as the header and content is placed into separate buffers for access via common definition.

Prior to the 7.0.00 release any WebSphere MQ message that contained a Dead Letter Header (DLH) resulted in the DLH, any subsequent MQ headers and remaining data placed in a message body buffer for parsing making it harder to use RFH2 or message content in a common way across activities.

Starting with the 7.0.00 release, the default is to place the DLH content into a Message MQDLH buffer, any RFH2 folder content placed in the Message RFH2 buffer and the remainder of the non-header data placed into the Message Body buffer. The behavior can be controlled on the Activity Implementation Extension Details tab via the "Parse MQDLH into data buffer" option but it is recommended new transaction pathways use the default of ON. Migrated models from a prior release continue to use the older mechanism.

In coordination with this change, the default MQDLH message format found in releases earlier than 7.0.00 which uses a Message Body buffer has been replaced with a WebSphere MQDLH message format which uses a Message MQDLH buffer. Profiles created with a release prior to 7.0.00 retain the old message format. New profiles only contain the new message format. The MQXQH structure describes the information that is prefixed to the application message data of messages when they are on transmission queues.