Functions of the Memory Management System

Features

An application runs in a work process where an ABAP program is normally executed. The process requires memory to do this, which is allocated to the process by the memory management system. The order in which the work process is assigned the memory type depends on the work process type, either dialog or non-dialog (see SAP Memory Types), and the underlying operating system.

The location of the various memory areas in the virtual address space is explained in Virtual Address Space of a Work Process.

The user context area that allows direct access can be extended as required when the size of the user context increases. For dialog work processes, the data of the user context, including internal tables is located in this extended memory. You can therefore access all the data in the user context. Only data of types extract and export to memory still remain in Paging.

The following diagram displays the memory types that can be assigned to work processes on SAP level and on operating system level. Here are the most important profile parameters that control the availability of the memory types.

The following graphic displays the roll action performed by the dispatcher.

The extended memory pool is the area of extended memory reserved for when the system is started.

• Roll-in: User-specific is shown in the work process by the extended memory pool so that it can be accessed in the next dialog step.
• Roll-out: After the dialog step has ended, the work process hides the user-specific data again in the extended memory pool.