Implementation Model Considerations (SAP Library - ITS Tuning and Troubleshooting Guide)

Implementation Model Considerations

Tuning an Internet Transaction Server (ITS) installation often depends on the implementation model(s) used to develop the applications driven by the ITS.

Here are some tuning considerations for:

SAP GUI for HTML
ITS Flow Logic
Web Reporting

SAP GUI for HTML

In terms of AGate performance, the SAP GUI for HTML is the most demanding implementation model, because it consumes large amounts of CPU and memory resources.

CPU Consumption

The SAP GUI for HTML consumes more CPU resources than the Web Transactions implementation model for several reasons:

More data has to be copied to the context

This also requires more memory operations.

The HTML templates generated are significantly more complex

Use of controls

With controls, the volume of data per screen received from the application server is considerably higher, so the number of data fields that have be set in the context is also much greater. This increases the amount of memory needed.

The check that verifies whether the date of an HTML^Business file has changed since the file was last precompiled and executed.

Although this operation has been in use for a long time, the CPU consumed by the SAP GUI for HTML is much greater than the Web transactions implementation model because the HTML^Business interpreter is called much more often.

The Web transactions implementation model calls the HTML^Business interpreter once for each R/3 screen
The SAP GUI for HTML calls the HTML^Business interpreter once for each dialog element

This behavior is useful in development and test systems, but is undesirable in production systems (and benchmark scenarios). For this reason, you can switch this check off by setting the value of the StaticTemplates parameter to 1 . For further information, see Setting Performance Parameters.

Memory Consumption

The SAP GUI for HTML consumes more memory than the Web Transactions implementation model for several reasons:

The number of screen fields and field attributes handled by the SAP GUI for HTML is much greater.

For this reason, the SAP GUI for HTML requires a lot more detail to be exposed to the HTML^Business interpreter.

The SAP GUI for HTML communicates with the HTML^Business interpreter using the context associated with the processing workthread. In order to handle the required amount of detail, the context must be fairly large.

Up to and including ITS Release 4.6A, the default context size was 2 MB
From ITS Release 4.6B, the default context size has been increased to 6 MB

This means an additional 4 MB of virtual address space for each workthread.

The time required to generate an HTML page and process all automation calls increases the processing time of requests on the server, so workthreads are kept longer. This increases the memory consumption of the server.

Sizing the ITS to handle the SAP GUI for HTML is difficult because the memory consumption per session depends largely on the amount of controls used in each transaction.

Average memory consumption for the Web transactions implementation model is about 150 KB, but it is difficult to estimate memory consumption for the SAP GUI for HTML because the transaction screen may or may not use controls.

Bottlenecks in SAP GUI for HTML Applications

At present, there are two potential bottlenecks:

Processing time of automation calls from the SAP R/3 application server

Processing time of the HTML^Business interpreter

To monitor the execution time, you can take the following steps:

Enable monitoring by adding the value Profiling with DWORD = 1 to the registry key

HKEY_LOCAL_MACHINE\Software\SAP\ITS\2.0\<ITS instance>\Programs\SAPjulep\

Open the file templates\system\dm\generatordhtml.html in a text editor.

Find the function page_begin()

Insert the code `htmlbusiness_resetcallstats()` at the beginning of the function

Find the function page_end()

Insert the code `htmlbusiness_showcallstats()` at the end of the function

Every page generated by the SAP GUI for HTML should now contain a detailed list of the functions called during the generation of the page, together with their execution times. If execution times are excessive, you should report the problem to SAP.

Caution

Adding the registry value Profiling to enable monitoring of the HTML ^Business interpreter affects performance, so you should not do this in production systems.

Screen-independent Applications Based on ITS Flow Logic

The most critical factor affecting consumption of resources in applications based on ITS Flow Logic is how long RFC connections are kept open.

Retention time of stateful connections is determined by the length of an ITS session
Retention time of stateless and pooled connections is determined by the time DDIC consistency must be maintained

DDIC consistency is guaranteed by retaining the connection. This ensures that the ITS session is still working on the same ABAP load, even though the ABAP source code or DDIC structures have changed during the session.

In development mode, DDIC consistency is maintained throughout a session
In production mode, DDIC consistency is maintained only for each call

In production systems, you should therefore set the value of the StaticBor parameter to 1 in ITS Administration. For further information, see Setting Performance Parameters.

Web Reporting

In Web Reporting, long-running reports retain workthreads for longer periods. This increases the number of workthreads required and results in higher memory consumption.