SAP performance testing guidelines

Before you test the performance of SAP applications, you must set up your test environment and incorporate these guidelines to produce reliable SAP performance tests.

SAP configuration

The SAP GUI client software must be installed on the same computer as IBM® Rational® Performance Tester. The SAP GUI client is required for recording and running performance tests. For information about support of SAP GUI versions, refer to the SAP Note 1412821 - SAP GUI for Windows: Support on Windows for SAP.

The product is optimized by default for SAP GUI version 7.10 or later. To improve performance with older SAP GUI 6.20 and 6.40 versions, when running long tests, you must change the bridge2java.dll file located in the C:\Program Files\IBM\SDP\plugins\com.ibm.rational.test.lt.runtime.sap\<build_identifier> directory by renaming bridge2java.dll to bridge2javaV7.dll, and then renaming bridge2javaV6.dll to bridge2java.dll.

If you are deploying tests on remote computers to simulate a large number of users, the following software must be installed on each remote computer:
  • The SAP GUI client software, configured with the same logon properties as the client on which the tests were recorded
  • TheIBM® Rational® Performance Tester Agent software that is provided with the product

Performance testing relies on the SAP Scripting API and ActiveX. Make sure that these options are selected when installing the SAP GUI client.

Performance test recording and running also require that scripting be enabled on the SAP application server and on all SAP GUI clients that are installed on remote computers. See the topic on configuring SAP for performance testing for more information.

Limitations

During playback of the performance tests, each virtual user runs SAP GUI in silent mode by default (the user interface is not displayed on the screen). However, some modal dialog boxes from the SAP GUI might briefly flash on the screen.

Avoid recording SAP tests with the SAP GUI low speed connection setting. You cannot run with a normal speed connection tests that you recorded with this setting.

You can have a maximum of only 50 virtual users on an agent for a SAP GUI test.

Batch input tests

You can use batch input tests to simulate a large number of virtual users while minimizing the load on the virtual user computers.

Batch input tests access the SAP server at a low level, bypassing the SAP GUI interface, and therefore cannot contain any verification points or SAP GUI elements. Their main purpose is to simulate a load on the server when added to a test schedule that already contains SAP performance tests. Only the SAP performance tests will provide accurate SAP application performance measurement.

Batch input transactions are recorded in the SAP GUI and exported to the file system. You can then generate batch input tests that are based on those recorded transactions.

Note: Sometimes the default values of the SAP Java Connectors (JCo) parameters are not sufficient for the load tests. The default values require some updates both at the SAP R/3 server and client end. For the client, in the Additional SAP Connection Properties window, you must configure the SAP JCo parameters options that are available in the test. Alternatively, you can specify the properties as RPT_VMARGS in the agent location. For example, RPT_VMARGS=- Djco.cpic_maxconv=1000

Performance tests

When deploying your performance tests, it is important to use a relevant number of virtual users on a given computer. For example, if you deploy too many virtual users on a single computer, the results produced will reflect more the load of the test computer than the load of the SAP application server.

For best results with performance tests on an average test computer with a 1 GHz processor and 1 GB of RAM, do not exceed 50 concurrent virtual users. With batch input tests, the maximum number of concurrent virtual users is approximately 500.

If you exceed the number of virtual users that a single test computer can run, the measured performance of the server will be affected by the performance of the test computer, which will invalidate the final results.

When editing a schedule for long performance tests, use these recommendations:
  • In the schedule editor, reduce the Test log level to None.
  • In the schedule editor, set the Statistics sample interval to approximately 1/60 of the run time, for example 12 minutes for an estimated 12-hour session.
  • When possible, use loops inside test suites rather than loops in the schedule. Using loops inside test suites avoids connection problems that might occur over long duration tests and emphasizes measurement of the actual SAP transactions rather than the logon process.

If you run a schedule that has an SAP test from Rational® Performance Tester Agent in Windows, you must then start Rational® Performance Tester Agent as a Process. However, Rational® Performance Tester Agent starts as a Service by default.

To start the agent as a process, you must perform the following steps:

  1. Open Windows Services.

  2. Change the Status of the Majordomo service from Running to Stop.

  3. Double-click the Majordomo file from the <SDP_Install_Directory>\Majordomo directory to run the agent as a compatible process.

Note: You must install SAP GUI in the agent computer to run a schedule that has an SAP test.

Long duration test runs

When running long duration test schedules that exceed many hours, use the long run mode process to reduce resource consumption with the SAP GUI client. This mode increases the reliability of long duration test runs because a new process starts every time the specified number of SAP sessions completes. Hence, Windows resource consumption is bare minimum. You must enable this option for each user group in the schedule.

In the long run mode, a new process is created each time the number of SAP test instances reaches the specified number.

For more information about how to run a long run mode test, see Running a long run mode SAP GUI test.

Cleaning the SAP work directory

In some cases, trace files are created by SAP GUI under SapWorkDir directory when running SAP performance tests. You can delete these files by setting and environment variable RPT_CLEAN_SAPWORKDIR or a java VMARG rptCleanSapWorkDir. For example:
  • -DrptCleanSapWorkDir=C:\Documents and Settings\UserName\SapWorkDir
  • RPT_CLEAN_SAPWORKDIR="C:\Users\UserName\AppData\Local\SAP\SAP GUI\Traces"

If you set the variable to the SapWorkDir folder location, the contents (*.trc files) of the folder are removed when a schedule starts. If the variable is set to true or on, the product automatically searches for the SapWorkDir folder before removing its contents. If the variable is set to false or off, no action is taken.