How To Fix RT066 - Buffer: Percentage usage of buffer memory

SAP Error Message - Details

• Message type: E = Error

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

• Message number: 066

• Message text: Buffer: Percentage usage of buffer memory

What causes this issue?

This monitoring tree element (MTE) shows the percentage of space that
has been allocated in a buffer.

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?

Alerts because a buffer is full must be evaluated with care. The reason:
by nature, buffers get full. SAP buffers use intelligent procedures to
replace old cached data with newly-required data. Finally, allocating
too much space to a buffer can cause other problems (operating system
paging) without significantly increasing the hit ratio (buffer quality).
The goal in buffer tuning is therefore to make a buffer large enough to
produce a high hit ratio with low swapping and minimal effect on
operating system paging.
Here are guidelines for deciding when to increase the size of particular
SAP buffers:
Enlarge a buffer if the swap rate (replacement of buffer objects) is
also high and/or the hit ratio is below the target threshold.
Enlarge a buffer if there are frequent alerts in this MTE. Frequent
alerts mean that the SAP buffer displacement mechanism is not able to
create enough free space for efficient buffer operation.
If possible, always increase the space available to the Generic Key
buffer if it becomes full.
The program buffer may be too small even if it still shows free space.
Enlarge the buffer or adjust the division of the buffer into sections
for large and small programs if the hit ratio is too low or swapping is
too high. Development systems need a larger-than-normal program buffer.
Increasing the size of a buffer requires that you do the following:
Change the system profile parameters that size the buffer; and
Increase the size of the SAP shared memory pools in which the buffers
reside. See the CCMS Guide to buffer monitoring (Help -> SAP Library ->
SAP NetWeaver -> Solution Life Cycle Managment -> Solution Monitoring ->
Monitoring in the CCMS -> SAP Buffers) help with these changes.
Monitor operating system paging for significant increases and monitor
SAP memory management MTEs in case of unwanted side effects after you
enlarge SAP buffers.
<DS:TX.SMOI_BUFFER_MANAGEMENT_INFO>Background Information</>

Error message extract from SAP system. Copyright SAP SE.

Smart SAP Assistant

• What is the cause and solution for SAP error message RT066 - Buffer: Percentage usage of buffer memory ?

  The SAP error message RT066 indicates that the percentage usage of buffer memory has reached a certain threshold, which can lead to performance issues or even system instability if not addressed. This message is typically related to the SAP memory management system, specifically the buffer management for various types of data (e.g., table buffers, area buffers, etc.).
  Cause:
  
  High Data Volume: The application may be processing a large volume of data, leading to increased buffer usage.
  Inefficient Buffer Configuration: The buffer sizes may not be optimally configured for the workload, leading to excessive usage.
  Frequent Data Changes: If the data in the tables is frequently changing, it can lead to higher buffer usage as the system tries to keep the most recent data in memory.
  Insufficient Memory Allocation: The system may not have enough memory allocated to handle the current workload effectively.
  
  Solution:
  
  Monitor Buffer Usage: Use transaction codes like ST02 (Tune Summary) to monitor buffer usage and identify which buffers are reaching their limits.
  Adjust Buffer Sizes: You can adjust the buffer sizes in the SAP profile parameters. For example, parameters like dbs/ora/area_size for Oracle databases or abap/buffersize for ABAP buffers can be modified.
  Increase Memory Allocation: If the system has sufficient hardware resources, consider increasing the overall memory allocation for the SAP instance.
  Optimize Data Access Patterns: Review and optimize the application code to reduce unnecessary data access and improve efficiency.
  Regular Maintenance: Implement regular database maintenance tasks, such as archiving old data, to reduce the amount of data that needs to be buffered.
  Check for Updates: Ensure that your SAP system is up to date with the latest patches and updates, as performance improvements and bug fixes can help with buffer management.
  
  Related Information:
  
  Transaction Codes: Use ST02 for buffer monitoring, SM12 for lock entries, and SM21 for system logs to gather more information about the system's performance.
  SAP Notes: Check SAP Notes related to buffer management and performance tuning for specific recommendations and best practices.
  Documentation: Refer to the SAP Help Portal for detailed documentation on memory management and buffer configuration.
  
  By addressing the underlying causes and implementing the suggested solutions, you can mitigate the RT066 error and improve the overall performance of your SAP system.