You can effectively check and troubleshoot RFC (Remote Function Call) errors in SAP by utilizing specific transaction codes and diagnostic tools, primarily focusing on the SM59 transaction for connection tests.
How to Check RFC Errors in SAP
Remote Function Calls (RFCs) are the standard SAP interface for communication between SAP systems or between SAP systems and external applications. When these connections fail, it's crucial to identify the root cause quickly.
1. Using Transaction SM59 (Display and Maintain RFC Destinations)
The primary tool for checking RFC connections and identifying potential errors is transaction SM59.
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Accessing SM59:
- Log in to your SAP system.
- Enter transaction code
SM59in the command field and press Enter.
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Performing a Connection Test:
- In the
SM59screen, navigate through the RFC destination tree (e.g., ABAP Connections, HTTP Connections, TCP/IP Connections) to locate the specific RFC destination you want to check. - Select the desired RFC destination by clicking on it.
- From the top menu or toolbar, choose the "Connection Test" button (or press
Ctrl+F8). - Successful Test: If the RFC connection is established correctly, a message similar to "Connection to system \
(host \ ) ok" will be displayed in the status bar. - Failed Test: If the test fails, an error message will appear, indicating the nature of the problem (e.g., "Host unknown," "Partner not reached," "Logon failed").
- In the
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Additional Tests in SM59:
- Authorization Test: For ABAP Connections, this test verifies if the user credentials configured in the RFC destination have the necessary authorizations to log on to the target system.
- Unicode Test: Checks if the RFC connection is compatible with Unicode systems.
2. Common RFC Error Messages and Troubleshooting
When an RFC connection test fails, the error message provides vital clues. Here's a table of common issues and their resolutions:
| Error Message / Code | Potential Cause | Troubleshooting Steps |
|---|---|---|
| Host unknown | Incorrect hostname or IP address in RFC destination. | Verify target host name/IP and DNS resolution. Ping the host from OS. |
| Partner not reached | Network issue, firewall blocking, target system down. | Check network connectivity (ping, telnet to port). Verify firewall rules. Ensure target system/service is running. |
| Logon failed | Incorrect user, password, or insufficient authorizations. | Verify user credentials in RFC destination. Check user status (locked/expired) and roles in target system. |
| Program not registered | Gateway service or external program not running. | For TCP/IP connections, ensure the external program is started and registered with the SAP Gateway. Check SMGW. |
| Timeout during RFC call | Network latency, performance issues, or long-running RFC function. | Check network speed. Review RFC function logic. Increase timeout settings (though often a symptom of other issues). |
| Error in RFC communication | Generic error, often related to underlying network or gateway. | Check SM21 (system log) and ST22 (dumps) in both source and target systems for more details. |
| Internal error in RFC library | SAP kernel or RFC library issue. | Update SAP kernel or RFC library. Contact SAP Support if persistent. |
3. Other Relevant SAP Transactions for RFC Error Analysis
While SM59 is central, several other transactions provide complementary information for diagnosing RFC issues:
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SM21(System Log):- Provides a chronological log of system events and errors, including communication issues related to RFCs. Look for entries concerning "Gateway," "RFC," or "Communication."
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ST22(ABAP Dump Analysis):- If an RFC call leads to an ABAP program termination, a short dump will be generated and can be analyzed here. The dump often provides precise details about the error's origin and the exact line of code that failed.
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SM58(Transactional RFC Monitor):- Used for monitoring tRFC (Transactional RFC) calls. If a tRFC fails, it remains in the queue (
SM58) and can be reprocessed or deleted. This is crucial for ensuring data consistency between systems.
- Used for monitoring tRFC (Transactional RFC) calls. If a tRFC fails, it remains in the queue (
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SMQ1(qRFC Outbound Queue) &SMQ2(qRFC Inbound Queue):- These transactions monitor qRFC (Queued RFC) entries, which ensure that RFC calls are processed in a specific order and are protected against system failures. Errors here often indicate issues with queue processing or target system availability.
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SMGW(Gateway Monitor):- Provides insights into the SAP Gateway processes, which manage connections for RFCs, particularly for TCP/IP and external programs. You can check:
- Logged-on clients: See which programs are connected to the gateway.
- Connections: View active RFC connections.
- Gateway parameters: Review configuration.
- Provides insights into the SAP Gateway processes, which manage connections for RFCs, particularly for TCP/IP and external programs. You can check:
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Operating System Level Tools:
ping: To check basic network connectivity between the SAP application server and the target host.telnet: To check if a specific port (e.g., SAP Gateway port 33or the application server port) on the target host is open and reachable. NIPING: An SAP-specific network diagnostic tool that can be used to test network connectivity and performance between SAP systems or between an SAP system and other hosts.
By systematically using these tools, you can effectively pinpoint the cause of RFC errors and implement the appropriate solutions.
