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ABAP Programs in AS ABAP

ABAP programs are executed on the Application Server ABAP (AS ABAP) of an ABAP system. The following figure shows a simplified representation of the AS ABAP as part of an ABAP system.

Figure

The AS ABAP represents the application layer of the ABAP system. The AS ABAP is identified by a system ID, which is also the name of the entire ABAP system. Users can log on to the AS ABAP using a user name. The most important components of an AS ABAP for ABAP program execution are:

  • AS Instance
The ABAP program execution itself takes place in AS Instances (application server instances). One or more AS Instances can be instantiated for an AS ABAP. Multiple AS Instances are usually distributed across several host computers. The AS Instances communicate with each other using a message server (exactly one for each AS ABAP).
  • Work processes
Each AS Instance uses its work processes to execute ABAP programs. There are various types of work processes for different applications: dialog, enqueue, background, spool, and update work processes. During the entire runtime of an AS Instance, each work process is logged on to the standard database of AS ABAP as a database user using a standard connection. This user is assigned the ABAP database schema that represents the database layer of an ABAP system. System programs, and system tables, and also application programs and application tables are stored in the ABAP database schema.
  • Communication components
The communication components connect the AS Instances with the presentation layer of the ABAP system, or with other systems, which can be either another AS ABAP or external systems. The following are examples of communication components:
  • A dispatcher for linking to SAP GUI.
Various protocols are used for communication, such as HTTP, HTTPS, TCP, or SAP's RFC protocol.

For more information, see Application Server Infrastructure - ABAP.

ABAP program execution is organized in sessions, which can access different memory areas:

Other versions: 7.31 | 7.40 | 7.54

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Sessions and Memory Areas

User Sessions

Programs in the Internal Session