Short text
Available main memory for the SAP instance
Parameter Description
The value defines how many megabytes of the main memory are to be used for the SAP instance. The default value for PHYS_MEMSIZE is the size of the main memory in megabytes. That is, it is automatically adjusted if the main memory configuration is changed.
With the value PHYS_MEMSIZE, the default values for the following memory management parameters are automatically calculated and you therefore do not need to maintain them manually.
em/initial_size_MB = (min(512000, $(PHYS_MEMSIZE) * 0.7))
em/max_size_MB = min(512000, $(PHYS_MEMSIZE) * 1.5))
rdisp/PG_SHM = (max(min(1000+40*max(5,floor(($(PHYS_MEMSIZE)-128)*25/128)),16384),1024)
On Windows:
abap/heap_area_total = ($(PHYS_MEMSIZE) * 1024 * 1024)
On all other platforms:
abap/heap_area_total = (max($(PHYS_MEMSIZE)*1024*1024 * 0.1, $(abap/heap_area_dia) * 2 ))
Aim
The new default values for memory management mean that you do not need to manually maintain the profile parameters. With PHYS_MEMSIZE, all memory management is calculated and adjusted. In this case, you only need to maintain this value if the SAP instance may not use the entire working memory.
Example 1
With a central instance with 1 GB of main memory, the database uses 400 MB and the application server uses 600 MB. In this case, manually set the value for PHYS_MEMSIZE to 600 in the instance profile. (No additional adjustments required)
Example 2
There are two dialog instances (for example, a production system and a test system) on one system (1 GB). With PHYS_MEMSIZE, the main memory is now divided between the two SAP instances.
For example: Production system
PHYS_MEMSIZE = 700
Test system
PHYS_MEMSIZE = 300
Example 3
A dialog instance on a host. That is, the SAP instance can use the entire main memory and it is therefore not necessary to manually maintain PHYS_MEMSIZE, because its default value is set to the size of the main memory.
Application Area
System
Parameter Unit
1 MB
Default Value
[Size of the main memory]
Who is permitted to make changes?
Customer
Note: PHYS_MEMSIZE only needs to be changed if the SAP instance is not permitted to use the entire working memory.
Are other parameters affected or dependent?
The default values for the following parameters are calculated directly from the value for PHYS_MEMSIZE:
em/initial_size_MB
em/max_size_MB
rdisp/PG_SHM
abap/heap_area_total
