Controlling CICS application connections

Every CICS transaction that issues calls to WebSphere MQ is assigned a unique thread ID to service the requests and keep track of changes made to WebSphere MQ resources. The thread ID is created the first time a transaction issues a WebSphere MQ request, and accompanies all subsequent WebSphere MQ requests made by that transaction.

While executing work under the CICS main task TCB, the CICS adapter queues WebSphere MQ requests for processing by any of the eight subtask TCBs. These subtask TCBs are attached by the adapter when the connection to WebSphere MQ is established.