How To Fix FL397 - &1 (type &2) can impair performance in RFC (with classic serialization)

SAP Error Message - Details

• Message type: E = Error

• Message class: FL - Function Builder messages

• Message number: 397

• Message text: &1 (type &2) can impair performance in RFC (with classic serialization)

What causes this issue?

This parameter contains a data type that can result in high memory
consumption and poor system performance when using the classic RFC
serialization. Performance is particularly badly affected if you have a
slow network connection (with high latency) or low bandwidth. This
affects IMPORTING, EXPORTING, and CHANGING parameters, which use deep
data types. Deep data types are tables or flat structures that contain
at least one field of variable length (for example, String/XString).

System Response

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

How to fix this error?

Use other serialization variants if possible. You can set these in
destination maintenance (transaction SM59).
The new fast serialization is always the fastest and is generally
compatible with classic serialization. Unfortunately, this serialization
is not available in older systems.
If your communication partner does not support the new serialization,
you can use basXML serialization (available in SAP NetWeaver 2007 and
higher). In destination maintenance, you can set either 'basXML' or
'basXML forced'. If you select 'basXML', the function module must be
available on the client side and the basXML flag must be set in the
function module. If you select 'basXML forced', it is not necessary to
select the 'basXML' property in the function module.
Caution: The basXML serialization serializes the data in an XML-like
intermediate format. When converted to text, there can be rounding
differences, for example, in binary floating point numbers. Also, errors
in the data content (for example, letters in NUMC fields) can result in
terminations.
If you cannot use the new serialization or the basXML protocol, please
check whether you can replace strings with fixed-length character
fields. Tables of structures that only contain fixed-length fields can
be transferred using the TABLES parameter (which gives significantly
better performance).
If you have decided on a new serialization or are prepared to accept the
effect on performance, you can suppress the warning with the pseudo
comment
<SE>##RFC_PERFORMANCE_OK</>
after the function statement.
Example:
<SE>FUNCTION MYFUNC ##RFC_PERFORMANCE_OK. </>

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.

Smart SAP Assistant

• What is the cause and solution for SAP error message FL397 - &1 (type &2) can impair performance in RFC (with classic serialization) ?

  The SAP error message FL397 indicates that there is a performance issue related to Remote Function Calls (RFC) due to classic serialization. This error typically arises when there are performance bottlenecks in the system caused by the way RFC calls are being handled, particularly when multiple calls are serialized, leading to delays and inefficiencies.
  Cause:
  
  Classic Serialization: This occurs when multiple RFC calls are made in a sequence, and the system processes them one after the other rather than in parallel. This can lead to increased response times and reduced throughput.
  High Load: If the system is under heavy load, it may exacerbate the serialization issue, leading to performance degradation.
  Inefficient RFC Calls: If the RFC calls themselves are not optimized or if they involve heavy processing, this can contribute to the performance issues.
  Network Latency: High latency in the network can also affect the performance of RFC calls, especially when they are serialized.
  
  Solution:
  
  Optimize RFC Calls: Review and optimize the RFC function modules to ensure they are efficient. This may involve reducing the amount of data being transferred or optimizing the logic within the function modules.
  Use Parallel Processing: Where possible, implement parallel processing for RFC calls instead of relying on classic serialization. This can be done using asynchronous RFC (aRFC) or transactional RFC (tRFC) to allow multiple calls to be processed simultaneously.
  Batch Processing: If applicable, consider batching multiple requests into a single RFC call to reduce the number of calls made and improve performance.
  Monitor System Performance: Use SAP performance monitoring tools to identify bottlenecks and areas for improvement. This can help in understanding the load on the system and the performance of individual RFC calls.
  Network Optimization: Ensure that the network infrastructure is optimized for low latency and high throughput to improve the performance of RFC calls.
  
  Related Information:
  
  SAP Notes: Check for any relevant SAP Notes that may provide additional insights or patches related to this error message.
  Transaction Codes: Use transaction codes like ST22 (Dump Analysis), SM21 (System Log), and ST03N (Workload Analysis) to analyze system performance and identify issues.
  RFC Monitoring: Use transaction code SM59 to monitor and configure RFC destinations, ensuring they are set up correctly for optimal performance.
  Documentation: Refer to SAP documentation on RFC performance tuning and best practices for further guidance.
  
  By addressing the causes and implementing the suggested solutions, you can mitigate the performance issues associated with the FL397 error message in SAP.