Load Testing: The Last Detail
By John Pearson
Successful Web design involves many considerations. They begin with the purpose of the site and anticipated target audience and continue on in ever-increasing detail to screen layout, database requirements, content management, and so on. However, one detail that's often an afterthought could lead to a catastrophic failure of the site. That detail is load testing, which lets you test how your site will perform under varying conditions. Load testing lets you manipulate (and simulate) some of the factors that affect performance, and measure their net effect.
What are some of these factors? First, there's the latency of merely sending data across the Internet. There's the effect of different access times for different users; there's time taken by the client to process client-side scripting or applets; then there's the time for the host to process server-side scripts; there's also time for any database interaction—or for data processing on the server side. The most important factor could be the number of people accessing your site.
Load testing tools can do the following for you:
- find performance bottlenecks,
- simulate different numbers of users at different connection speeds,
- test different access paths with different parameters,
- measure the effects of different conditions on different parts of the system simultaneously,
- measure response times,
- compare results.
Two tools available in this space are Mercury Interactive's Astra LoadTest and RadView's WebLoad.
