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difference between Synchronous and Asynchronous and Transactional RFC ?

Hi all,

What is the difference between Synchronous and Asynchronous and Transactional RFC ?

Thanks in advance





The called function module is executed exactly once in the RFC server system. The remote

system need not be available at the time when the RFC client program is executing a tRFC. The

tRFC component stores the called RFC function together with the corresponding data in the R/3

database, including a unique transaction identifier (TID).

If a call is sent, and the receiving system is down, the call remains in the local queue until a later

time. The calling dialog program can proceed without waiting to see whether or not the remote

call was successful. If the receiving system does not become active within a certain amount of

time, the call is scheduled to run in batch.

Transactional RFCs use the suffix IN BACKGROUND TASK.


The characteristics of qRFC with send queue are:

Queued RFC with send queue enforces a serialization on the side of the send system. The

target system has no information about the serialization in the send system. This allows

communication with any R/3 target system as of Release 3.0.

qRFC with send queue is an enhancement of tRFC. It transfers an LUW (transaction) only if

it has no predecessors (in reference to the sequence defined in different application

programs) in the participating queues. In addition, after executing a qRFC transaction, the

system tries to start all waiting qRFC transactions automatically according to the sequence.

For queue administration, the system needs a queue name and a queue counter for each

qRFC transaction. Each tRFC call to be serialized is assigned to a queue name that can be

determined by the application. The application passes the queue name with the call of

function module TRFC_SET_QUEUE_NAME. This function module is called immediately

before each tRFC call to be serialized. See also Programming Serialization [Page 28].

A queue name is a text of up to 24 bytes length. You can choose any text, but you must not

use * (asterisk).


Asynchronous remote function calls (aRFCs) are similar to transactional RFCs, in that the user

does not have to wait for their completion before continuing the calling dialog. There are three

characteristics, however, that distinguish asynchronous RFCs from transactional RFCs:

When the caller starts an asynchronous RFC, the called server must be available to

accept the request.

The parameters of asynchronous RFCs are not logged to the database, but sent directly

to the server.

Asynchronous RFCs allow the user to carry on an interactive dialog with the remote


The calling program can receive results from the asynchronous RFC.

You can use asynchronous remote function calls whenever you need to establish communication

with a remote system, but do not want to wait for the function’s result before continuing

processing. Asynchronous RFCs can also be sent to the same system. In this case, the system

opens a new session (or window) and allows you to switch back and forth between the calling

dialog and the called session.

To start a remote function call asynchronously, use the following syntax:


Destination ...





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