saptec1 unit3 supakorn kungpisdan [email protected]
TRANSCRIPT
SAPTEC 2
Business Example
In the course of implementing an SAP system, you need to establish the architecture of SAP systems and how you are going to distribute the required SAP system processes among the available hardware
SAPTEC 3
Introduction
SAP systems are used for mapping business processes or business applications.
These applications should be implemented independent of the hardware environment used (OS, DB) to the greatest extent possible.
SAP Web AS Application Server provides two runtime environments: ABAP runtime environment Java runtime environment
SAPTEC 4
Introduction (cont’d)
ABAP (Advanced Business Application Programming) is developed by SAP Use ABAP workbench for developing SAP application
Since Web AS 6.20, SAP provides Java runtime environment Integrate J2EE and called “SAP Web AS Java”
SAPTEC 5
Client and Server: Terminology Definition
Hardware-oriented view Server is a central server in
a network providing resources for client (workstation)
Software-oriented view Both client and server are
processes
SAPTEC 6
Client/Server Configuration for SAP Systems
The following processes are required for operating business application software: Presentation processes (e.g. for displaying screens) Application processes (e.g. for executing application
programs) Database processes (e.g. for managing and organizing
DB data)
SAPTEC 7
Client/Server Configuration for SAP Systems (cont’d)
SAPTEC 8
Client/Server Configuration for SAP Systems (cont’d) Single tier
Used for tests and demonstrations Incur extra cost for increased users
Two tier With distributed presentation processes, it can maintain good
performance for a significantly higher number of users Load from presentation processes is distributed to the various
front-end computers. So it does not influence the performance of the DB host
Three tier Distribute application layer to several hosts to reduce
bottlenecks More that three tier: may include web server level
SAPTEC 9
Architecture of ABAP Applications
BSP = business server page used for developing web applications on SAP Web AS Application Server
SAPTEC 10
Architecture of Java Applications
SAPTEC 11
SAP Web AS Processes
SAPTEC 12
SAP Web AS Processes (cont’d)
In ABAP environment, ABAP dispatcher manages different types of work processes
(WP) Dialog WPs fulfill all requests.
Every dispatcher requires at least two dialog WPs Spool WPs pass sequential data flow to printers
Can have more than one spool per dispatcher Update WPs execute update requests
Need at least one update per dispatcher Can have more than one per dispatcher
Background WPs execute programs that run without interacting with the user
Need at least 2 backgrounds per SAP system Enqueue WP administers the lock table in shared memory
Need only 1 enqueue per system
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SAP Work Processes
Type Use
DIA Responsible for dialog requests
UPD Responsible for update
UPD2 Exclusively responsible for less time-critical update (optional)
BGD Executes background jobs
SPO Processes output requests
ENQ Responsible for locks
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SAP Web AS Processes (cont’d)
ABAP runtime system provides additional services for internal and external communications: Message Server (MS) handles the communications between
the distributed dispatchers within the ABAP stack of an SAP system
One dispatcher per instance Enabling scalability of several parallel application servers
Gateway Server (GW) enables communications between SAP systems, or between SAP systems and external application systems
Internet Communication Manager (ICM) enables SAP systems to communicate directly with the Internet
Direct HTTP request from an SAP system to a web server and send the response back to the SAP system
Can have ICM per instance
SAPTEC 15
The instance
Instance is an administrative unit that combines SAP system components providing one or more services
SAPTEC 16
Instance in the ABAP+Java Environment
JCo = Java Connector
SAPTEC 17
Instance in the ABAP+Java Environment (cont’d)
SAPTEC 18
Types of the SAP Web AS
SAPTEC 19
Possible User Requests in the SAP System
SAPTEC 20
Dialog Processing in the SAP System
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Structure of a Work Process
Work processes execute dialog steps for applications programs
A work process has a task handler that coordinates the actions within a work process, two software processors and a database interface
SAP application programs differentiate between user interaction and processing logic
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Structure of a Work Process
The user interactions are technically realized using screens, also called dynpros (dynamic programs) Consist of screen image and underlying flow
logic. Screen flow logic is divided into PBO (process before output): is processed before
the screen image is sent and PAI (process after input): is processed after a user
interaction on the screen
SAPTEC 23
Processing flow for dialog steps
SAPTEC 24
Communication with the Database
Within ABAP, you can use SAP Open SQL to access the application data in the database, regardless of the RDBMS used.
The database interface, which is part of every WP on the SAP Web AS, translates Open SQL statements from ABAP into the corresponding SQl statements for the specific DB used (Native SQL).
This allows ABAP programs to be DB-independent.
SAPTEC 25
Communication with the Database (cont’d)
Native SQL commands can be used to directly in ABAP without local buffer and db interface
However, you can no longer maintain the platform independence of the affected programs
SAPTEC 26
Communication with the Database
The SAP Web AS Database Interface
SAPTEC 27
DB Transactions and SAP Transactions
SAPTEC 28
Fundamentals of Enqueue Processing in SAP Systems
SAPTEC 29
Requesting a Lock Entry
SAPTEC 30
Update Processing
SAPTEC 31
Update Processing (cont’d)