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Meaning of 'maximum address space' in ST22?

Former Member
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Hello experts!

Can someone tell me what the meaning of the maximum adress space is? I see this value in ST22 after some dumps because of a lack of main memory and I want to understand the meaning of this parameter to make a better interpretation of the dump.

Best regards,

Peter

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Answers (1)

Answers (1)

Former Member
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Hi,

You might have a 32bs OS ?

The following notes are describing some problems related to lack of address space (contiguous block).

Note 129813 - Windows: Problems due to address space fragmentation

Note 853696 - Preloading DLLs to Avoid Address Space Fragmentation

Try to have the Address Space Viewer (only for 32 bits OS issues !! or a 32 bits XI on a 64bits OS) via a SAP note. The tool has a good help document describing the address space concept in details.

Also some info from a document we have (Optimizing the Memory settings for SAP systems on 32 bits OS):

""

How is the Memory Addressed in the Process?

Every Windows process can address up to 4 GB (232-1) of virtual memory in its own address space. This

memory consists of 2 parts: the user part (where the user program can allocate the memory) and the kernel

part. Under normal circumstances, both parts are 2 GB.

The user part of the virtual address space can be increased by activating the /3GB option in boot.ini. This

is called “4GT”. 4GT tuning is possible as of Windows 2000 Advanced Server and Windows Server 2003

(Standard, Enterprise and Datacenter Editions). To use 4GT, the option large address aware bit (LAB) must

be set by the software vendor in the 32bit EXE file. For example, disp+work.exe has LAB activated by

default, java.exe does not.

As of Windows Server 2003 it is also possible to differentiate between the user part and the kernel part of

the virtual address space with the /USERVA option.

If the 32-bit process runs on 64-bit Windows, the user part of the virtual address space is 4 GB. ""

What you must check is that there is at least a SHM block of your VAS (virtual address space) big enough to contains fully what you have defined for your abap/buffer (related to the size of your work process). If the block is too small, you will see swap in the transaction ST02.

Voila

Gaetan Nys