One of my key tasks at Wine.com (the Magenic project for which we were awarded Microsoft's 2005 Worldwide Partner of the Year Award for a Custom Development Solution) was architecting a sales tax calculation Web service capable of supporting the tremendous volumes of traffic encountered by the main Wine.com Web site. The software package I used for this purpose was a Web service-testing package that just happened to have some load-testing functionality built into it. One of the things I like best about RadView's WebLOAD product is that it is 100 percent focused just on load testing - allowing for much more breadth and depth of functionality within this category. The way that the product works is illustrated in Figure 1.

You begin by creating a test script that details the various operations that you want to perform as a part of the load testing of your Web application. On one hand, WebLOAD allows you to create some pretty darned complex scripts without ever manually entering a single line of code through its advanced visual environment. On the other hand, if you need to do something so specific to your exact business case that it can't be done through the visual editor, you can also tweak - or completely hand-code - a test script using industry-standard JavaScript.

Once your script has been written you can run it through WebLOAD. WebLOAD is multi-threaded, meaning that it can generate requests from many, many simulated clients simultaneously. Alternatively, or in conjunction, you can install WebLOAD on multiple computers to increase the amount of generated test load against your application many times over.

WebLOAD's ability to simulate numerous popular Web browsers while making requests is one of its nicest features. On the client side, it can consume such esoteric functionality as ActiveX controls and Java applets. It can imitate browsers ranging from old versions of Internet Explorer to new versions of Firefox.

While this load is being sent to your Web application, WebLOAD is also recording intricate data about how your application responds. This performance data is sent back to the WebLOAD console where a number of reports about it can be generated. These reports can be rendered in the form of standard tabular data for you to pour through at your leisure, either on the screen or in printed form. Additionally, WebLOAD is capable of generating a number of graphs to help you more quickly understand the shape of the data you are dealing with, and to help you more easily spot potential problems in your application.

Possibly the nicest single feature of WebLOAD, when it's paired with WebLOAD analyzer, is its ability to perform root-cause analysis if and when your application finally breaks under the load. What this means, in short, is that when you finally find your application's breaking point, WebLOAD won't just tell you that your application broke, it will tell you why it broke - which is often the most important piece of information!

As a side note, I should mention that WebLoad also supports various J2EE application servers - although I had no desire or ability to test WebLOAD's functionality against these as a part of this review.