Dynamic registration and extended transactional processing

Use dynamic registration is a form of optimization because it can reduce the number of xa_ function calls issued by the transaction manager.

If a queue manager does not use dynamic registration, a transaction manager involves the queue manager in every unit of work. The transaction manager does this by calling xa_start, xa_end, and xa_prepare, even if the queue manager has no resources that are updated within the unit of work.

If a queue manager uses dynamic registration, a transaction manager starts by assuming that the queue manager is not involved in a unit of work, and does not call xa_start. The queue manager then becomes involved in the unit of work only if its resources are updated within sync point control. If this occurs, the extended transactional client calls ax_reg to register the queue manager's involvement.