1. Overview SAP Basis Functions

2. SAP Technical Overview
Learning Objectives
What the Basis system is
How does SAP handle a transaction request
Differentiating between the various work processes
Understanding the basic functions of the Basis Module
SAP Technical Overview

3. The Software-Oriented View of R/3
SAP Technical Overview

4. The SAP R/3 System Architecture
Implications for Application Programming
Separate presentation and application layers implies that when you run an application program that requires user interaction, control of the program is continually passed backwards and forwards between layers.
When a screen is ready for user input, the presentation layer is active, and the application server is inactive with regard to that particular program.
As a consequence, the program logic in an application program that occurs between two screens is known as a DIALOG STEP.
SAP Technical Overview

5. SAP Technical Overview

6. The SAP R/3 System Architecture
Application Layer (cont.)
Application Server
R/3 programs run on application servers
The APPLICATION SERVER communicate with the presentation components, the database, and also with each other, using a MESSAGE SERVER.
Main components:
Work Processes (Dialog, Update, Enqueue, Batch, Spool)
Dispatcher
Gateway
Message Server
SAP Technical Overview

7. What happens when I send a request to SAP?

8. SAP Technical Overview
Application Server
Presentation Internet
SAPGUI
SAPGUI
Office
Internet
TCP/IP
Communication
Application
Dispatcher
IPC
Work-
process
Work-
process
Work-
process
Local Buffer
for R/3 Data,
DW-Objects,
ABAP-Objects
This slide depicts how an application server works. Users make requests at the presentation layer and through TCP/IP these requests get sent to the application server. The dispatcher then takes the requests and assign them to work processes which handle the requests. More detailed explanations are on the following slides.
Remote SQL
Database
SAP Technical Overview

9. SAP Technical Overview
Dispatcher
Program which manages resources of the R/3 applications
Receives requests from user and passes them to the corresponding work processes
Only one dispatcher per application server
The dispatcher is a program which manages the resources of the R/3 applications. They are very similar to a police dispatcher who receives requests via 911 and routes it to available officers who are in the area.
The dispatcher receives requests from the many users on the system and passes them along to the corresponding work processes which are free. It also manages the information flow between the app server and the SAPGUI.
Each app server has only one dispatcher because it could get kind of difficult for two dispatchers to route requests to the work processes.
SAP Technical Overview

10. SAP Technical Overview
Dispatcher Tasks
Balances the workload between the processes
Buffer management in main memory
Connection with the presentation level
Organization of the communication processes
The dispatcher is responsible for balancing the workload between the work processes so that processes don’t sit idle.
Memory management is also one of its duties. The dispatcher must also organize the communication between the work processes and also between the SAPGUI and app server.
SAP Technical Overview

11. SAP Technical Overview
Work Process
Responsible for executing R/3 application tasks
Task Handler
ABAP/4
Processor
Dialog
Interpreter
Database
Interface
Work processes are the actual programs which execute tasks. They update the database, run batch programs, and send messages. Work processes are comprised of a task handler, an ABAP/4 processor, dialog interpreter and database interface.
They execute dialog steps for a user and typically only do the work of displaying one screen at a time. In other words, work processes present one screen of data, and are immediately freed to handle other tasks. The next screen is then handled by the next available work process.
The task handler coordinates the activities of the work process. The database interface allows for the work process to directly access the database. The dialog interpreter is used to coordinate presentation information and the ABAP/4 processor is useful when running programs.
Work Process
SAP Technical Overview

12. Different Kind of Work Processes for different Tasks
Dialog
Update
Message D V M
Batch
SAP Dispatcher
Enqueue 12 9 6 3 11 1 7 5 8 4 2 10 E
Spool B S
Gateway
There are seven different types of work processes which will be described in detail in the following slides. The five work processes in the middle around the dispatcher are the main work processes in use in the application servers. The two work processes on the outside are used for communication methods within the systems.
R/2 G
R/3
SAP Technical Overview

13. SAP Technical Overview
Dialog Work Processes
Responsible for the interactive tasks of the R/3 system
Dialog work processes execute only one dialog step at a time and are immediately freed for the next user request
Constantly switching between users
Dialog D
The dialog work process is typically the most common work process. It handles all the interactive requests of the R/3 system. Any time a user sends a request the dialog work process plays a part in the work. Dialog work processes handle just one dialog step and are immediately freed to handle other requests. So these work processes are constantly switching between users. This limits the number of dialog work processes, as you would need the same number of work processes as users otherwise.
SAP Technical Overview

14. Background Work Processes
Responsible for executing ABAP programs submitted for background execution
Batch jobs schedule the sequence of program execution
Used for running long and time consuming programs
Batch 12 9 6 3 11 1 7 5 8 4 2 10 B
Background work processes execute long running and CPU intensive programs which are required to be run. Some examples include client copies and long listing reports.
Background jobs can also be set to run at specific times.
SAP Technical Overview

15. SAP Technical Overview
Spool Work Processes
Responsible for formatting the data for printing and passing it to the host spool system
Only one spool work process allowed per server
Spool
In charge of formatting data for printing and sending it to the host spool system. Only one spool work process per host.
SAP Technical Overview

16. Enqueue Work Processes
Responsible for the lock management system
Synchronizes database access for the multiple application servers and work processes
Only one enqueue process per R/3 system to ensure data integrity
Enqueue E
In order to ensure the integrity of the database, the enqueue work process is responsible for the lock management system. There is only one enqueue work process per system as it synchronizes the data access for multiple application servers and work processes. When a work process is accessing data for possible manipulation it is locked so that other work processes cannot access the data until it is released.
SAP Technical Overview

17. SAP Technical Overview
Update Work Processes
Responsible for making database changes requested by dialog and background processes
For better performance, this process should be on the database server
Update V
Update work processes actually manipulate the database, so they would be better served to be on the actual database server. They make all the changes to the database within the R/3 system.
SAP Technical Overview

18. SAP Technical Overview
V1 vs. V2 Update Processes
Time-critical processes are inside V1 and less critical ones within V2
Error situations in
V1 : changes rolled back and V2 components not executed
V2 : only changes of V2 components rolled back
Update V
SAP makes distinctions between the V1 and V2 component. V1 contains the time critical processes that require immediate updating whereas V2 processes are less critical. During updates there can be a combination of V1 and V2 updates.
When errors occur during the V1 update, all changes are rolled back and any subsequent V2 components are not executed. Errors occurring the the V2 phase requires that only changes in the V2 component be rolled back.
SAP Technical Overview

19. SAP Technical Overview
Message Server
Used by different application servers to exchange data and internal messages
Routes messages, such as update or batch job starts, between application servers
One message server per system
Message M
This single message server per system sends messages between the various application servers. Messages include update or batch job starts. The communication is setup through the dispatchers and is used for small internal messages.
SAP Technical Overview

20. SAP Technical Overview
Gateway Server
Allows communication between R/3, R/2, and external applications
Exchanges large amounts of information between application servers
Gateway can reside on any of the connected systems
Gateway
R/2 G
R/3
Gateways connect the R/3 system to other systems such as R/2 or other external systems. They facilitate the transfer of large amounts of data through the use of TCP/IP.
SAP Technical Overview

21. SAP Technical Overview
Work Processes
Number of work processes can only be changed after restarting the system
Should have at least two dialog work processes
Need to have at least one V1 and V2 processes
Number of spool processes cannot be changed
In order to change the number of work processes, you must change the system profile and restart the system.
A system should have at least two dialog work processes at all times to ensure correct usage. In case something is wrong, an administrator would need to be able to interactively log on to the system.
You need to have at least one V1 and V2 work processes in order to make updates.
SAP Technical Overview

22. SAP Technical Overview
Application Server
Presentation Internet
SAPGUI
SAPGUI
Office
Internet
TCP/IP
Communication
Application
Dispatcher
IPC
Work-
process
Work-
process
Work-
process
Local Buffer
for R/3 Data,
DW-Objects,
ABAP-Objects
Remote SQL
Database
Back to our picture.
SAP Technical Overview

23. Processing of a SAP Transaction (1)
Presentation Internet
SAPGUI 1
Start
Transaction
TCP/IP 5
Communication
Application
Re-
turn
data
for
next
step 2
Dispatcher
Assign User
request to
Workprocess
IPC 4
The following outlines the course of events for an application:
1) The user sends a request to the app server.
2) The dispatcher receives the request and assigns it to a work process.
3) The work process looks in its buffer for the requested data.
4) It finds the data and once it finishes handling the request it sends the result back to the dispatcher.
5) The dispatcher formats the results and sends it back to the SAPGUI.
Work-
process
Work-
process
Work-
process
Local Buffer
for R/3 Data, 3
DW-Objects,
ABAP-Objects
Fetch data from buffer/database
Remote SQL
Database
SAP Technical Overview

24. Processing of a SAP Transaction (2)
Presentation Internet
SAPGUI 1 6
TCP/IP 10 5
Re-
turn
data
for
next
step
Communication
Application 2
Dispatcher 7
IPC
Assign User
request to
Workprocess 9
6) The user makes another request of the system.
7) The dispatcher receives the request and assigns it to a work process
8) The work process retrieves data from the buffer or the database
9) The work process handles the request by interacting with the database and sends it back to the dispatcher
10) The dispatcher sends the data back to the user
Work-
process
Work-
process
Work-
process
Local Buffer
for R/3 Data, 3
DW-Objects,
ABAP-Objects 8
Remote SQL
Database
Fetch data from
buffer/database
SAP Technical Overview

25. Processing of a SAP Transaction (3)
Presentation Internet
SAPGUI
Request
for update 1 6 11
TCP/IP 10 5
Communication
Application 2
Dispatcher 7 12
IPC 9 4
Work-
process
Work-
process
Work-
process
11) Say the user requests an update. A request is sent to the dispatcher.
12) The dispatcher sends the request to the work process.
13) The work process makes the change to the database
14) The transaction ends.
Local Buffer
for R/3 Data, 3
DW-Objects,
ABAP-Objects 8 14
End transaction
Remote SQL 13
Database
Update data
on database
SAP Technical Overview

26. SAP Communication Interfaces
SAP Technology
High
Level
Business API
Mail
MAPI
SMTP
X.400
ALE
OLE
EDI
IDOC
RFC
This slide shows the various communication interfaces in the R/3 system. The ones closer to the top are the ones which implementers are most likely to work directly with. The ones at the bottom are more of internal SAP communication interfaces.
Q-API
Low
level
CPI-C
Communication System
SAP Technical Overview

27. SAP Technical Overview
Business Framework
ALE
Business
Component
Business
Component
BAPI
BAPI
Business Component - contains business functionality
BAPI - interface between the components
ALE - integration of components
The Business Framework - the open, component-based architecture, which allows software components from SAP and third parties to interact and integrate with each other, is gaining more and more momentum.
Business Components cover a broad range of business data and processes. Examples include customer order management, purchase requisitions, and invoices.
Business API (BAPI) are methods which allow interfacing between the various business componenets.
ALE - provides an interface between the various components
SAP Technical Overview

28. SAP Technical Overview
Business API (BAPI)
Defined method of a business object
Standardized methods allow customers to integrate their software with R/3
Object-oriented in nature
BAPIs from all development platforms that support the SAP Remote Function Call (RFC) protocol
BAPI’s are merely methods within Business components. They allow outside applications to access those Business componenets. They are standardized methods which allow integration. It’s also object oriented in nature.
SAP Technical Overview

29. SAP Technical Overview
Other Interfaces
Application Link Enabled (ALE) - Interface that links different SAP systems and external application systems
Transport special data structures known as IDOCS (Intermediate Documents)
Object Linking and Enabled (OLE) - enables desktop users to access SAP data from many OLE client programs
SAP Technical Overview

30. Basic Functions of Basis

31. SAP Technical Overview
Basis Functions
Hardware and Database Administration
User and Security Administration
Client Maintenance
Correction and Transport System (CTS)
Data Dictionary
Online Service System (OSS)
Performance Monitoring and Tuning
Here are some of the most important functions of Basis personnel.
SAP Technical Overview

32. Hardware and Database Administration
Hardware upgrades - adding memory or servers
Database backup and recovery
Database optimization
Disaster Recovery
Some of the responsibilities of Basis personnel include the maintenance and upkeep of the hardware and database as other typical system administrators do. Typically, sizing, upgrading, backup and recovering are some of the issues that are dealt with.
SAP Technical Overview

33. SAP Technical Overview
User Administration
Create users and assign profiles
Modify, lock and unlock users
Develop authorizations and profiles
One of the big tasks of Basis personnel is User Administration. Users must be made and assigned the correct profiles so that they can do their job and not have any extra access to other transactions that they should not be able to view.
SAP Technical Overview

34. SAP Technical Overview
Client Maintenance
Create clients
Copy and refresh clients
Client imports and exports
Delete and remove clients
Modify change options
Client maintenance involves the creating of clients and running client copies and refreshes.
Client exports and imports occurs when you wish to take a client from one system and move it to another. Exports make a file at the operating system level, which can then be imported into the target system.
When clients are obsolete, they must be deleted in order to be more efficient with memory.
SAP Technical Overview

35. Correction and Transport System
R/3 System
R/3 System
R/3 System
Change
Request
Quality Assurance
Production
Development
CTS is the notion of moving changes from one system to another. In the typical Development-Testing-Production environment, CTS is the mechanism of moving changes and modifications through the systems.
Moving changes from one R/3 system to another
SAP Technical Overview

36. Online Service System (OSS)
OSS is a set of SAP’s online services such as bug fixes and useful implementation information
OSS Notes
Hotpacks
Remote Connections
Send questions to SAP
ABAP registration
OSS is SAP’s online service system, which contains known problem, bug fixes, and news. It’s a great source of information to find answers to your problems, and even affords you the opportunity to send SAP questions that have stumped you. OSS also plays a role in ABAP development, as all ABAP programmers must be registered through OSS.
SAP Technical Overview

37. Performance Monitoring and Tuning
Check database usage and storage capabilities
Dialog response time
Investigate ABAP short dumps
Optimize performance characteristics
SAP Technical Overview

38. Computer Center Management System (CCMS)
Manages the entire system - database, application, operating system
Collection of tools and utilities which allow you to monitor and manage the R/3 system
Allows monitoring of multiple R/3 systems
Comes FREE with each SAP system
SAP Technical Overview

39. Computer Center Management System (CCMS) functions
Starting and stopping instances
Monitoring and analyzing workload
Alert capabilities
Operation modes and work process automatic reconfiguration
Instance profile checking and maintenance
Logon load balancing
SAP Technical Overview