01. SAP Introduction

21. Response Time

Response Time

The time it takes to get from step 1 (user request) to step 7 is known as response time. The response time is one of the main indicators of how healthy (well−tuned) the system is.

A SAP instance profile parameter controls the maximum allowed time for interactive execution of a dialog step: rdisp/max_wprun_time.

The default value for this parameter is 300, When this value is reached, the dispatcher stops the work process and the user gets a TIME_OUT error.

An instance is an administrative entity that groups together R/3 components which offer one or several services. These offered services are started or stopped together. All instance components are configured using a common instance profile.

In sap there are two types of instance central instances and dialog instances SAP distinguishes between central instances and dialog instances. Every SAP system has just one central instance, which contains all basic services such as the message server, gateway, update, enqueue, dialog, spool, and background right from installation. Dialog instances, as defined, only contain a set of basic services such as dialog and background work processes from the time of installation.

19. Memory Area

Memory Area

SAP use following type of memory

01. Physical :- (RAM) OS, WP, Listener.
02. Extended: - (Hard disk) Database.
03. Virtual: - (Page file) CI.

18. DIAG PROTOCOL

DIAG PROTOCOL

The connection between the SAPGUIs and the SAP dispatcher is made with an optimized protocol, known as DIAG, in which small data packages are sent through the network.

17. Gateway Server

Gateway Server

The gateway service allows the communication between R/3, R/2, and external applications. This service is a CPIC handler which implements the CPIC protocol for communication.

16. Message Server

Message Server

The message server is a service used by the different application servers to exchange data and internal messages.

Every application server has a unique name for the message server.

The location of the host running the message server is configured in the DEFAULT.PFL common profile. The parameter is rdisp/mshost = <hostname>.

15. Update Work Process

Update Work Process

The update work process is in charge of executing database changes when requested by the dialog or background work processes.

An update request can contain a primary update component (V1) and several secondary ones (V2). The time critical processes are held inside the V1, the less critical within the V2. In order to be able to initiate the V2 components of the log record, the V1 component must have finished.

The other parameters, rdisp/wp_no_vb and rdisp/wp_no_vb2