Basics of memory

SAP Roll Area

SAP Extended Memory

SAP Heap memory

SAP Buffer

Agenda

Sap Memory Management

Physical memory and Virtual memory

Basics of Memory

Virtual memory

Paging File

&

Sap Memory Management

Physical memory

/

OS Swap Space

&

Local memory and shared memory

Basics of Memory

Local memoryWorkprocess

Virtual memory

Sap Memory Management

All work processes of one instance

Local memory

Shared Memory

Workprocess

SAP Roll Memory

SAP Roll Memory

� Local SAP Roll area of work process

- The initial part of user context stored

- Each SAP work process can only access its own roll area

�Shared SAP Roll Area

Sap Memory Management

�Shared SAP Roll Area

- Accessible to all of instance work processes

- Buffer to temporary keep user context when a user is assigned to new work process

- Roll in : copying user context from shared roll area to local roll area

- Roll Out : copying user context from local roll area to shared roll area

SAP Roll Memory

Roll buffer (shared memory)Roll area

(local)

Roll file (disk)

Roll area (local)

Work Process1

Work Process2

copy copy

Sap Memory Management

Roll file

Roll (local)

Roll Buffer (shared)

Roll In / Roll Out

ztta/roll_first

ztta/roll_area

SAP Extended Memory

�Extended memory is the heart of the memory system

�Shared memory in which objects, data, internal tables associated with individual users are stored

� All SAP work process can edit stored user context directly

SAP Extended Memory

Sap Memory Management

� All SAP work process can edit stored user context directly

�Each WP has a part of memory reserved in extended memory

� Makes roll process much faster

SAP Extended Memory

Memory allocation for Dialog WP

Extended MemoryHeap

memory

Roll

Area 2

Roll

Area

1

Sap Memory Management

Extended Memory used up Roll

memory used up

WP has entered in PRIV Mode

SAP Heap Memory

SAP Heap Memory

•It is used when Extended and roll memory are full.

•It is allocated and released on demand.

•It is the part of the Local memory

Sap Memory Management

SAP Heap Memory

Sap Memory Management

SAP Buffer/Client Cache

SAP Buffer

• When the object is used frequently, it is moved to the buffer.

• HIT Ratio

• SWAP Rate

Sap Memory Management

• Types of buffer :

1) Repository Buffer

2) Table buffer

3) Prog Buffer

4) SAP GUI Buffer

5) Calendar Buffer

6 ) Export/Import Buffer

SAP Buffer

Sap Memory Management