Those who develop or support 5250-based transaction applications running on the iSeries have many tools at their disposal for managing the performance of those applications. System commands such as WRKSYSSTS (Work with System Status) and WRKACTJOB (Work with Active Jobs) provide valuable information about key performance metrics such as transaction response time and transaction throughput.
Beyond the core operating system utilities, the reports in the Performance Tools licensed product or the Performance Management (PM) iSeries service offering let you track transaction performance metrics on a historical basis. When performance problems arise in an application of this kind, trace facilities invoked with the STRPFRTRC (Start Performance Trace) command can analyze individual transactions and identify causes of performance bottlenecks, such as a lock on a database record or program.
But what happens when a 5250-based application is changed or replaced with new technologies that use Web servers, application servers, and database technologies such as ODBC? The ability to analyze transaction performance becomes more complicated because tools such as WRKSYSSTS and the commonly used Performance Tools reports do not provide a measure of transaction performance for the non-5250 environment.
Fortunately, iSeries tools are available that can help you understand the mystery of application performance in this new world. It starts with a very powerful tool called the Performance Explorer (PEX). PEX has been available in OS/400 for many years, but few iSeries professionals have used it to help analyze application performance.