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Dokumentation

RSMEMORY - Set Memory Strategy

Description

This program allows you to define both the size and the sequence of the individual memory areas in the SAP memory. You can thus set different values and sequences for dialog and background processes.

• Dialog:
  
  Initially, dialog processes always require a small roll area (500,000 - 1,000,000 bytes). Further memory space is requested from the EM (extended memory) area which allows the user to switch to other work processes. This area is divided among all the users working on the application server. If the EM value is 200,000,000 bytes, a user can request this amount of memory from the EM area. This means that the other users may then get much less. If the roll area and the EM memory are exhausted, there is still some heap memory left. Since heap memory cannot switch contexts, it is assigned to the requesting user and is not available to other users. Only when the user has released all the memory from the heap can other users use this work process. For this reason, the requesting of heap memory in dialog processes must be an execption because the number of work processes cannot be increased indefinitely.
  

• Background/update/spool:
  
  These processes usually satisfy their memory requirements from the heap memory. When this is exhausted, memory is requested from the EM area (this makes sense because few dialog processes are active at night and the EM memory is otherwise unused).

Displaying the memory areas:

By selecting Goto -> EM/HEAP areas, you can output a list of all users on the application server with their memory requirements.
This is followed by a list of users who have used more memory than the limit determined by em/stat_log_size_MB.
At the end of the list, the amount of heap and EM memory still available is displayed.