Memory Management 101 – WebAs ABAP
1. SAP memory area
- em/initial_size_MB = overall em, set large enough.
- ztta/roll_extention = overall em limit per workprocess.
- abap/heap_area_dia & abap/heap_area_nondia = limits for heap usage for dia/non dia. If set higher, OS swap be used.
- abap/heap_area_total = limits for all dia and non-dia heap usage
- abap/heaplimit = to allow wp restart AFTER it completed execution to free memory, usually small.
- rdisp/PG_SHM & rdisp/PG_MAXFS = shm 10% or maxfs
- rdisp/ROLL_SHM & rdisp/ROLL_MAXFS = maxfs can be set to big.
- SAP buffers as seen in ST02
Note:
- Both em and heap uses swap space, ensure swap file is increased correspondingly.
- For unix ensure shm pools (e.g HP-ux pool 10 and 40) are enough.
- Note 425207 SAP memory management, current parameter ranges
2. ST02 storage report
- Storage shared between wp = total usage for sap buffers. they take hp-ux pool.
- user storage for each wp = mem of each wp x total number of wp
- size of ext = em/initial_size_MB set.
- virtual mem allocated = mem req for sap.
3. Allocation sequence
- DIA = roll area > em > heap
- NONDIA = roll area >heap > em
- Use RSMEMORY to redefine seq. (0 – Roll area, 1 – Ext Memory, 2 - Heap)
- SAP Note 177226 Documentation rsmemory
