How To Fix RT067 - Buffer: Hit rate

SAP Error Message - Details

• Message type: E = Error

• Message class: RT - Monitoring infrastructure MSG and alert texts

• Message number: 067

• Message text: Buffer: Hit rate

What causes this issue?

This monitoring tree element (MTE) shows the hit ratio of a buffer. The
hit ratio is a measure of the quality or performance of the buffer. It
is the percentage of database requests that could be satisfied from the
buffer, without requiring the involvement of the database.

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?

Hit ratio alerts mean that poor buffer performance is reducing the
performance of the application server. The buffers in the alert monitor
are critical to good instance performance. You should therefore analyze
the buffer quality problem and take corrective action.
In general, poor buffer quality means that a buffer is too small. If a
buffer is too small, then the chances increase that requested objects
(table entries, programs, and so on) will not be found in it. The
result is a lower hit ratio, and, if the buffer is already full,
increased swapping. Swapping increases as requested objects force older
objects out of the buffer.
To improve the hit ratio, you should generally increase the size of a
buffer.
Use the analysis method for this buffer to analyze the performance of
the buffer before you enlarge it. Be sure that no temporary problem has
reduced the buffer's quality. (All buffers perform poorly during a
warm-up phase after the system or an application server starts. The
monitoring architecture does not issue buffer alerts during a best-guess
warm-up period).
Further, the performance of the program buffer may be reduced if
developers are working in a system or if objects are being imported into
the system with the SAP transport system.
<DS:TX.SMOI_BUFFER_MANAGEMENT_INFO>Background Information</>
See also the descriptive message for buffer free space and the CCMS
Guide under Help -> SAP Library -> SAP NetWeaver -> System Life Cycle
Management -> Solution Monitoring -> Monitoring in the CCMS.

Error message extract from SAP system. Copyright SAP SE.

Smart SAP Assistant

• What is the cause and solution for SAP error message RT067 - Buffer: Hit rate ?

  The SAP error message RT067, which pertains to "Buffer: Hit rate," typically indicates an issue with the performance of the SAP buffer management system. This message is related to the efficiency of the buffer, which is a temporary storage area that holds data to reduce the time it takes to access frequently used information.
  Cause:
  The RT067 message is usually triggered when the hit rate of the buffer falls below an acceptable threshold. A low hit rate means that the system is frequently accessing the database instead of retrieving data from the buffer, which can lead to performance degradation. Common causes include:
  
  Insufficient Buffer Size: The buffer may not be large enough to hold the frequently accessed data.
  High Data Volume: An increase in the volume of data being processed can lead to a lower hit rate.
  Inefficient Buffer Configuration: The buffer may not be optimally configured for the specific workload or data access patterns.
  Data Changes: Frequent changes to the data can lead to cache misses, as the buffer may not have the most current data.
  
  Solution:
  To address the RT067 error and improve the buffer hit rate, consider the following solutions:
  
  
  Increase Buffer Size: Adjust the buffer size in the SAP system configuration to accommodate more data. This can be done in the SAP profile parameters (e.g., abap/buffersize).
  
  
  Optimize Buffer Configuration: Review and optimize the buffer configuration settings. This may involve adjusting parameters related to the specific types of buffers (e.g., table buffers, object buffers).
  
  
  Monitor and Analyze Usage: Use transaction codes like ST02 (Tune Summary) to monitor buffer performance and analyze hit rates. This can help identify specific areas that need improvement.
  
  
  Regular Maintenance: Perform regular maintenance tasks, such as clearing the buffer or reorganizing tables, to ensure that the buffer remains efficient.
  
  
  Review Data Access Patterns: Analyze how data is accessed in the application. If certain tables are accessed more frequently, consider adjusting the buffer settings for those specific tables.
  
  
  Consult SAP Notes: Check for any relevant SAP Notes that may provide additional guidance or patches related to buffer management.
  
  
  Related Information:
  
  Transaction Codes: Use transaction codes like ST02 (Buffer Monitor) and ST04 (Database Performance Monitor) to analyze buffer performance and database access.
  SAP Documentation: Refer to SAP Help documentation for detailed information on buffer management and configuration.
  Performance Tuning: Consider engaging with SAP Basis consultants for performance tuning and optimization strategies tailored to your specific environment.
  
  By addressing the underlying causes and implementing the suggested solutions, you can improve the buffer hit rate and enhance the overall performance of your SAP system.