SWAT: A Tool for Stress Testing Session-based Web Applications

Stress testing is essential for effective sizing, capacity planning, and service level management exercises. Unfortunately such testing can be a difficult and time-consuming process. In particular, for session-based Web applications, it is difficult to create synthetic workload traces that simultaneously satisfy inter-request dependencies and match the parameter values of many other attributes of real workloads. This paper describes a workload modeling and generation tool for stress testing session-based Web applications. The Session-based Web Application Tester (SWAT) is a tool built on top of the open source httperf Web request generator. It has features to deduce a compact and flexible representation of complex session-based application workloads, to control the generation of synthetic workload traces for sensitivity analysis exercises, and to efficiently submit synthetic workload traces to a system under study. In this way, SWAT aims to facilitate the stress testing process. We demonstrate the use of SWAT with a case study involving a TPC-W compliant e-commerce system. Experiments show that the workload attributes request mix, session length distribution, and think time distribution can each affect client response time distribution as measured in a controlled environment. We show that SWAT can be used to simultaneously control the parameters of such attributes and therefore support studies that evaluate the sensitivity of system capacity to a range of workload conditions.