ABAP Shared Objects

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Copyright © 2013 Accenture All Rights Reserved. Accenture, its logo, and Accenture High Performance Delivered are trademarks of Accenture.

ABAP Shared Objects 25 th June 2014


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Today’s Agenda

As a result of this session, you will be able to:

• Understand the concepts of ABAP Shared Objects• Decide when (not) to use ABAP Shared Objects

• Define shared memory areas• Store data in shared memory areas• Access data in shared memory areas• Adapt shared memory areas for your needs• Monitor shared memory areas

Copyright © 2013 Accenture All Rights Reserved.


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What is Shared Memory ?

• The shared memory is a memory area on an application server,which is accessed by all of this server’s ABAP programs. Beforeshared objects were implemented, ABAP programs could accessthis memory area using the EXPORT and IMPORT statements

exclusively with the SHARED BUFFER or SHARED MEMORYadditions, and instances of classes or anonymous data objectsexisted exclusively in the internal session of an ABAP program.

• With the implementation of shared objects with Release 6.40, theshared memory was enhanced with the shared objects memorythat stores shared objects.


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What is Shared Memory ?

Different kinds of main memory on an application server

Session Memory

Bound to a single user session Cannot be accessed by a different user sessionGuarantees user isolation

Shared Memory (SHM) Shared across session boundaries

No user isolation Requires access control in a business application context

Application development has longed for buffering data in shared memory fora long time


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Data Access without Buffering



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SAP ILM

Data Access with Buffering by Copy



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Data Access with in Place Buffering



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SAP BW

Informat ionaldata for al l

repor t ing needs

ExtractTransform

Load

SAP DART

Significant boost in overall performance due toReduced memory consumption

Data is kept only once in memory

Reduced runtime costs Data is aggregated only once Fast access at main memory speed In place aggregation for “arbitrary” data structures including strings, internal tables,and references

Reduced maintenance costs due to Simplified programming model in contrast to solutions based on IMPORT / EXPORT

Workbench navigation Data is aggregated only once Ported to ABAP Shared Objects Saves 3 MB session memory per user About 100 times faster at first access

Benefits for Application Programming



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SAP BW

Informat ionaldata for al l

repor t ing needs

ExtractTransform

Load

SAP DARTAn area is the template for area instances in the shared memory.Several area instances can be created from one area instance,

differing from each other in name. Moreover, there can be severalversions of an area instance (area instance versions), which differfrom each other by a version identifier. All area instance versions ofthe same area instance name make up an area instance. In thesimplest case (without versioning), an area instance consists of a

single area instance version.

Areas and Area Instances



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Areas and Area Instances


Shared object memoryPart of the shared memoryCustomizable by profile parameter

Shared object areasOrganizational units (type)Defined at design timeIdentified by unique name

Shared object area instances

Content stored at runtimeUnique name within the areaSingle-instance area addressed bydefault name


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Area Classes and Area Handles


When an area is defined in Transaction SHMA , a global and final areaclass with the same name is generated as a subclass ofCL_SHM_AREA. Class CL_SHM_AREA itself is a direct subclass ofCL_ABAP_MEMORY_AREA.

In an ABAP program, an area is accessed exclusively using themethods of the generated area class. There are static methods forbinding an ABAP program (or its internal session) to area instances inthe shared memory (attach methods).Binding creates an instance of the area class as an area handle, and

creates a lock at the same time. The ABAP program can access thebound area instance version using the area handle and thus access theshared objects that are stored there. The area handle also contains themethods for deleting the connection or the lock (detach methods).

http://help.sap.com/saphelp_nw04s/helpdata/en/13/dc853f11ed0617e10000000a114084/content.htmhttp://help.sap.com/saphelp_nw04s/helpdata/en/13/dc853f11ed0617e10000000a114084/content.htm


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Area Instances and Objects



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Design Time Support

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Definition of a Shared Memory Area



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Abstract Area Class



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Drivers Locking Concept



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Attaching to an Area Instance


Define


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Example: Write Access



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Detaching from an Area Instance



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Example: Detach from Write Access



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Shared Objects Area Monitor

ABAP Shared Objects

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