WebSphere MQ Workflow

WebSphere MQ Workflow on z/OS is a tool which helps companies improve their business processes. z/OS workload manager (WLM) addresses the need for:

• Managing workload distribution
• Load balancing
• Distribution of computing resources to competing workloads

WebSphere MQ support for z/OS workload manager introduces a new type of local queue: a WLM-managed queue. It is recognized by a new value of the INDXTYPE attribute called MSGTOKEN. The initiation queue associated with a WLM-managed queue should have TRIGTYPE defined as NONE and no ordinary local queues should be associated with this initiation queue.

If a WebSphere MQ Workflow server application has the initiation queue open for input, WebSphere MQ updates a WLM worklist as part of commit processing of MQPUTs to the WLM-managed queue. The setting of TRIGGER or NOTRIGGER on the WLM-managed queue has no effect on the updating of this WLM worklist.

The PROCESS definition is used to provide the name of the application_environment associated with a WLM-managed queue. This is passed in the APPLICID attribute. You should ensure that a WLM-managed queue uniquely references an associated process and that two processes do not specify the same APPLICID value.

Messages are retrieved from a WLM-managed queue using a unique message_token which must be passed to MQGET. To do this, a new message_token value (MQGMO_MSGTOKEN) and a new get message match option (MQMO_MATCH_MSG_TOKEN) are used. Workflow does not normally issue MQGET calls until the message is placed successfully on the queue. If the application needs to wait for the arrival of a message, it must set the match option to MQMO_NONE.

There are new MQRC values for MQGET (MQRC_MSG_TOKEN_ERROR) and MQPUT (MQRC_MISSING_WIH and MQRC_WIH_ERROR). MQRC_MISSING_WIH is returned if a message, MQPUT to a WLM-managed queue, does not include the new work information header (MQWIH). MQRC_WIH_ERROR is returned if the message data does not conform to an MQWIH. MQGET does not remove this header from the message.

Note:

You may experience excessive CPU usage if your z/OS system is at Version 2.5 or earlier and the number of messages on WLM-managed queues exceeds 500.

For further information see IBM WebSphere MQ Workflow:Concepts and Architecture, GH12-6285 and IBM WebSphere MQ Workflow for z/OS:Customization and Administration, SC33-7030.