Implementation on Windows

Use

The basis for the Zero Administration Memory Management on Windows is the dynamic extended memory. The technique provides you with a nearly unlimited memory resource. Initially, the extended memory is set to the size of the profile parameter PHYS_MEMSIZE[PM]. If the user requires more memory, extended memory extends itself in steps of min (2 GB) from "[PM] / 2" up to the set limits in the profile parameter em/max_size_MB, or until the address space in the Windows page file is used up. By setting the default value for em/max_size_MB to 1.5 * [PM] for 64-bit Windows platforms, the size of the Windows page file represents the actual limit for extending the extended memory. The profile parameter PHYS_MEMSIZE determines how much of the total main memory is used by the SAP system. The default value for PHYS_MEMSIZE is the size of the main memory [MM].

Sequence of allocating memory for nondialog work processes:

  1. Extended memory until the limit min {em/address_space_MB, ztta/roll_extension_dia} for dialog work processes, and min(em/address_space_MB, ztta/roll_extension_nondia) for non-dialog work processes.

  2. Heap memory until the limit abap/heap_area_dia, abap/heap_area_total, abap/heap_area_nondia, depending on the work process type and how much memory is currently allocated by all work processes of an instance.

The basis for zero administration memory management is a sufficiently large Windows page file. For more information about the Windows paging file size, see the installation guide for your SAP product.

All relevant memory management parameters are set with an optimal default value so that all manual configurations are unnecessary.