abap/heap_area_total: Heap Memory Limit

Use

This sets the upper limit for the heap memory that all work processes of an R/3 application server can allocate. You can use this upper limit to restrict the swap space usage of an R/3 application server to a specific amount. You can find more details on this topic under Functions of the R/3 Memory Management System.

Goal:

This value ensures that even at maximum swap space usage of the R/3 System and during normal operation, at least 100 MB swap space (or approximately 10-15%) remains free.

Integration

• Swap space size in the system. In addition to the system and R/3 requirements, another swap space reserve of at least 100 MB should be available. You can find more details on this topic under
Swap Space Requirements and Functions of the R/3 Memory Management System.
• R/3 Extended Memory pool size (parameter em/initial_size_MB). The swap space size that an R/3 server can fill orients itself primarily according to the R/3 Extended Memory pool and the value of this parameter.

Activities

Unit: Bytes

Default value: 800000000 (800 MB)

Recommended value: A general value cannot be specified here. The deciding factor for the setting is the available swap space. You must set the parameter to the following value:

• physical memory + swap space - allocated virtual memory

You can monitor physical memory and swap space using Transaction ST06 (see Checking Unused Working Memory using Transaction ST06) Allocated virtual memory consists of allocated memory from:

• All R/3 instances
• Database buffers and database processes
• Operating system, special file system cache

You can view this using Transaction ST02 ® Detail Analysis Menu ® Storage.

You can find the values from the configuration examples (Contents button): Setting Up the Memory Management System

Changes: Customers can make changes.