The IMS trigger monitor

The IMS trigger monitor (CSQQTRMN) is a WebSphere MQ-supplied IMS application that starts an IMS transaction when a WebSphere MQ event occurs, for example, when a message is put onto a specific queue.

 

How it works

When a message is put onto an application message queue, a trigger is generated if the trigger conditions are met. The queue manager then writes a message (containing some user-defined data), known as a trigger message, to the initiation queue that has been specified for that message queue. In an IMS environment, we can start an instance of CSQQTRMN to monitor an initiation queue and to retrieve the trigger messages from it as they arrive. Typically, CSQQTRMN schedules another IMS transaction by an INSERT (ISRT) to the IMS message queue. The started IMS application reads the message from the application message queue and then processes it. CSQQTRMN must run as a non-message BMP.

Each copy of CSQQTRMN services a single initiation queue. When it has started, the trigger monitor runs until WebSphere MQ or IMS ends.

The APPLCTN macro for CSQQTRMN must specify SCHDTYP=PARALLEL.

Because the trigger monitor is a batch-oriented BMP, IMS transactions that are started by the trigger monitor contain the following:

• Blanks in the LTERM field of the IOPCB

• The PSB name of the trigger monitor BMP in the Userid field of the IOPCB

If the target IMS transaction is protected by Security Server (previously known as RACF), you might need to define CSQQTRMN as a user ID to Security Server.