How To Fix 00851 - Extended memory: high-water mark since startup

SAP Error Message - Details

• Message type: E = Error

• Message class: 00 -

• Message number: 851

• Message text: Extended memory: high-water mark since startup

Self-Explanatory Message

Since SAP believes that this specific error message is 'self-explanatory,' no more information has been given.The majority of messages in the SAP system have a message text, however this is frequently insufficient to comprehend or resolve the problem.

To make things easier, more detailed information is frequently added to describe the issue, how to fix it, and the necessary steps or configuration modifications.

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Smart SAP Assistant

• What is the cause and solution for SAP error message 00851 - Extended memory: high-water mark since startup ?

  The SAP error message "00851 Extended memory: high-water mark since startup" indicates that the extended memory usage in the SAP system has reached a critical level. This message is a warning that the system is using a significant amount of its allocated extended memory, which can lead to performance issues or even system instability if not addressed.
  Cause:
  
  High Memory Usage: The primary cause of this error is that the SAP system is consuming a large amount of extended memory, which is used for storing data and program code.
  Inefficient Programs: Poorly designed ABAP programs or transactions that consume excessive memory can lead to high memory usage.
  Large Number of Users: A high number of concurrent users can increase memory consumption, especially if many users are running memory-intensive transactions.
  Configuration Issues: Incorrect configuration of memory parameters in the SAP system can lead to inefficient memory usage.
  
  Solution:
  
  Monitor Memory Usage: Use transaction codes like SM04 (User Overview) and SM50 (Process Overview) to monitor which users and processes are consuming the most memory.
  Analyze ABAP Programs: Check for any custom ABAP programs that may be consuming excessive memory. Optimize these programs if necessary.
  Adjust Memory Parameters: Review and adjust the memory parameters in the SAP profile (e.g., abap/heap_area_dia, abap/heap_area_nondia, abap/heap_area_total) to allocate more memory if needed.
  Increase Extended Memory: If the system is consistently reaching high-water marks, consider increasing the extended memory allocation in the instance profile.
  Restart the Instance: In some cases, a restart of the SAP instance may temporarily alleviate the issue, but it is not a long-term solution.
  Check for Memory Leaks: Investigate if there are any memory leaks in the system that need to be addressed.
  
  Related Information:
  
  SAP Notes: Check SAP Notes related to memory management and performance tuning for specific recommendations and best practices.
  SAP Memory Management: Familiarize yourself with SAP's memory management architecture, including the different types of memory (e.g., roll memory, heap memory, extended memory).
  Performance Monitoring Tools: Utilize SAP's performance monitoring tools (like ST03N for workload analysis) to identify performance bottlenecks and memory usage patterns.
  
  By addressing the underlying causes and optimizing memory usage, you can mitigate the occurrence of the "00851 Extended memory: high-water mark since startup" error and improve the overall performance of your SAP system.