SAP Memory Management

 

SAP Memory Management:

                        

                      While working on SAP ABAP systems, we often facing memory-related "DUMPS" error in "ST22" or some time see work processes go in "PRIV mode" when checked in t-code "SM50". We wondering why such things happen in running in the SAP system and how to handle it. To understand this, we first need to understand what "SAP memory" is and how "SAP Memory Management" is done. So let’s get start to know the basic concept of SAP Memory management.

What is SAP Memory:

                    

                SAP memory is a memory area to which all main sessions within an "SAP GUI" have access. You can use SAP memory either to pass data from one program to another within a session or to 

pass data from one session to another.

Workflow for SAP Memory:

               When a user logon to an application server instance (AS instance) in the ABAP system, a user session is opened. Within a session, the user sends a request to Application Server ABAP (ASABAP). An ABAP program is started that is executed by multiple work processes. A separate memory area is assigned to each user session. 

              To run an ABAP program within a user session (internal session), the work process allocates memory, which contains user data (user context), as well as program data. Depending on the type of data, it is located in different memory areas. SAP Memory Management decides when and in what order a work process allocates specific memory areas. The order of memory allocation depends on the work process type (dialog or non-dialog) and on the underlying operating system.

Types of SAP Memory 

On a very high level, there are mainly two types of memory areas in SAP 

1.  Extended Memory (EM) 
2.  Heap Memory 

If we go a little deeper, then we have in total 6 memory areas 

1. SAP Shared Memory (SHM) 
2. Extended Segments Memory (ES) 
3. Extended Memory (EM) 
4. Global Extended Memory (EG) 
5. PRIV Memory (HEAP) 
6. PROC Memory 

We will see upcoming post IN details about SAP Memory types.

• SAP Memory types
• SAP Shared Memory (SHM)
• SAP Extended Segments Memory (ES)
• SAP Extended Memory (EM)
  
• SAP Global Extended Memory (EG)
  
• SAP PRIV Memory (HEAP)
  
• SAP PROC Memory

Some additional Information see the below blog post.

• SAP Memory Area Allocation Sequence
• SAP list of key SAP Memory parameters
  
• SAP Memory Management - Monitoring
  

Reference:

1. help.sap.com 
2. SAP Notes 
3. Linkedin