Communication Between tp and ABAP 

Transport steps that are implemented in ABAP include activating ABAP Dictionary objects, structure conversion, and generating reports and screens. Executing these steps is complicated. The program tp uses the tables TRBAT and TRJOB to communicate with the ABAP transport programs.

To execute these steps, the SAP system must be running with at least two background work processes. Furthermore, the background job RDDIMPDP must be scheduled with the repeat-start option. We recommend scheduling this job event on a regular basis. If this job is not running, start the program RDDNEWPP once in client 000 in each client using a user that has the CTS administrator authorization S_CTS_ADMIN.

Once tp has sent the corresponding event to the SAP system, RDDIMPDP checks table TRBAT to see if there is anything to do. If there is, it starts the required programs (for example, mass activation) in the background, schedules itself again, and then stops.

RDDIMPDP automatically recognizes if a previous step was terminated and restarts the action. However, this can only be done with two background work processes.

RDDIMPDP recognizes terminated import steps by checking table TRJOB.