Introduction to the DB2 Connect performance tests

Objective

DB2 Connect Enterprise Edition V9.1 for Linux on zSeries (DB2 Connect) connects LAN-based systems and their applications to the company's mainframe host DB2 databases. Additionally, DB2 Connect can be used in a three tier environment and can act as a gateway concentrating large numbers of SQL connections from various clients to a fewer, well-defined number of connections to the DB2 database on z/OS®.

The focus of this report was on the connection concentrator functions of DB2 Connect. This feature enables a predictable, controlled load on the database on z/OS from a DB2 Connect server and may reduce mainframe resource usage as fewer DB2 threads may be defined. The capacity of active connections from the DB2 Connect gateway to the z/OS DB2 database was dependent on the resources available on the DB2 Connect gateway. The scaling behavior from DB2 Connect for the number of CPUs, memory, and various connection concentration levels were examined.

DB2 Connect was hosted on Linux for System z™, which was implemented together with the WebSphere® Application Server environment as z/VM® guests. This setup provided an integrated solution with DB2 Connect providing gateway and connection concentration for a three tier environment with the Trade 6 workload and gateway and connection concentration in a two tier environment with the IBM® Relational Warehouse Workload (IRWW). The two application workloads, Trade 6 and IRWW, with their different architectures were tested to examine how application implementation characteristics might affect settings for optimal performance.

The objectives of this project were to analyze the performance of DB2 Connect environments. The information in this paper should not be used to develop capacity sizing rules-of-thumb for customer environments. For sizing and capacity planning, contact our specialists from the IBM System z sizing team.

Executive summary

This paper shows the results from our performance measurements with environments using DB2 Connect Enterprise Edition. For our workload, a DB2 Connect system with 1 GB of main memory and up to 2 virtual CPUs was suitable for all cases. The use of the connection concentrator function of DB2 Connect was a suitable tool to control the load on the DB2 database, but it requires specific prerequisites on DB2 and WebSphere Application Server settings as well as the characteristics of the workload itself. The impact of DB2 Connect on the throughput in the three tier environment was very small. It was higher in the two tier environment. Additionally, we identified the Workload Manager (WLM) settings on z/OS as an important parameter for database performance.