How To Fix 00859 - Maximum number of extended memory management slots

SAP Error Message - Details

• Message type: E = Error

• Message class: 00 -

• Message number: 859

• Message text: Maximum number of extended memory management slots

What causes this issue?

Each internal session needs one such extended memory slot. (Each
external session can contain up to 9 internal sessions).

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?

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 00859 - Maximum number of extended memory management slots ?

  The SAP error message "00859 Maximum number of extended memory management slots" typically indicates that the system has reached the limit of extended memory management slots that can be allocated for processes. This can occur in environments where there are many users or processes running simultaneously, leading to a depletion of available memory slots.
  Cause:
  
  Memory Configuration: The SAP system has a limit on the number of extended memory management slots, which is determined by the configuration settings in the instance profile.
  High Load: A high number of concurrent users or background jobs can lead to the exhaustion of available memory slots.
  Inefficient Memory Usage: Some processes may not be releasing memory properly, leading to a situation where the slots are not being reused effectively.
  
  Solution:
  
  
  Increase Extended Memory Slots:
  
  You can increase the number of extended memory management slots by adjusting the instance profile parameters. Look for the parameter em/initial_size_MB and em/size_MB in the instance profile.
  Example: If the current setting is too low, you might increase it to a higher value, depending on your system's available memory.
  
  
  
  Monitor and Optimize Memory Usage:
  
  Use transaction codes like ST02 (Tune Summary) to monitor memory usage and identify any processes that are consuming excessive memory.
  Analyze the workload and optimize the performance of long-running or resource-intensive jobs.
  
  
  
  Restart the Instance:
  
  In some cases, a simple restart of the SAP instance can free up memory slots that are no longer in use.
  
  
  
  Check for Memory Leaks:
  
  Investigate if there are any memory leaks in custom programs or third-party add-ons that may be causing excessive memory consumption.
  
  
  
  Upgrade Hardware:
  
  If the system consistently runs out of memory slots, consider upgrading the hardware to provide more memory resources.
  
  
  
  Related Information:
  
  SAP Notes: Check SAP Notes related to memory management and performance tuning for specific recommendations and best practices.
  SAP Documentation: Review the official SAP documentation for detailed information on memory management parameters and their implications.
  System Monitoring Tools: Utilize SAP monitoring tools (like SAP Solution Manager) to keep track of system performance and memory usage trends over time.
  
  By addressing the configuration and monitoring the system's memory usage, you can mitigate the occurrence of this error and improve overall system performance.