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 Process documentation Transactional RFC (tRFC)  Locate the document in its SAP Library structure

 

When using transactional RFC (tRFC), the called function module is executed exactly once in the called system (service property: Exactly Once).

The remote system does not have to be available when the RFC client program is executing a tRFC. The tRFC component stores the called RFC function in the SAP system database under a unique transaction number (TID), along with the corresponding data.

If a call is sent, and the receiving system is down, the call remains in the local queue. The calling dialog program can proceed without waiting to see whether 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.

As with synchronous calls, the DESTINATION parameter defines a program context in the remote system. If you call a function module with the same destination several times (or several function modules once), you can therefore access the global data for the called function module in the same context.

The system logs the remote call request in database tables ARFCSSTATE and ARFCSDATA with all parameter values. You can display the log file using transaction SM58. When the calling program reaches a COMMIT WORK, the remote call is forwarded to the requested system.

All tRFCs with a single destination that occur between one COMMIT WORK and the next belong to a single logical unit of work (LUW).

 

tRFC Process Flow Diagram

This graphic is explained in the accompanying text

You can use transactional RFCs, for example, for complex processes that require updating of related database tables during different phases in a transaction.

Transactional RFC processing ensures that all the planned updates are carried out when the program reaches the COMMIT WORK statement.

Caution

Function modules that are called transactionally cannot have any EXPORT parameters in their definition, as a corresponding IMPORTING parameter in the calling program causes syntax errors.

Note also that you cannot make asynchronous calls to functions that perform call-backs.

System Availability

If the remote system is unavailable, the SAP System uses the relevant transaction ID (TID) to schedule report RSARFCSE as a background processing variant. This report, which forwards asynchronous calls for execution, is called repeatedly until it succeeds in connecting with the system in question.

When scheduled in batch, RSARFCSE runs automatically at set intervals (the default setting is for up to 30 attempts at 15 minute intervals). You can customize this interval and the length of time the program should carry on trying for. Use enhancement programs SABP0000 and SABP0003 to do this.

To configure a destination, call transaction SM59, select the screen for a destination and choose Edit TRFC Options. This enables you to set the maximum number of connection attempts and the intervals at which they are made.

If the system cannot be reached within the specified amount of time, the system stops calling RSARFCSE, and the status CPICERR is written to the ARFCSDATA table. Within another specified time (the default is eight days), the corresponding entry in the ARFCSSTATE table will be deleted (this limit can also be customized). It is still possible to start this type of entry manually in transaction SM59. 

 

Further Information

      You can find a description of the statements for tRFC in:

      CALL FUNCTION IN BACKGROUND TASK 

 

 

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