This section contains important tips and configuration guidelines for problem situations that may occur when using qRFC with outbound queue.

• You can use the QOUT Scheduler to determine how many work processes are used for sending the LUWs.
• Because most external server programs are not multithreading-compatible, only one work process should be used for sending to external servers. You can make this setting for every destination in transaction SMQS.
• The serialization is performed by the SAP Gateway.

While the server program is busy processing a LUW, all subsequent tRFC LUWs must wait in the SAP Gateway until the server program is ready again, or until a timeout (default: 1 minute). A timeout schedules a batch job for restarting each LUW (this setting can be made in SM59).

If you have registered the same server program at an SAP Gateway more than once with the same program ID to achieve faster parallel processing of the RFC calls, you should still assign more than one work process for processing the LUWs for this destination.