Developing Web Applications

A Note About Application Testing

Performance testing, especially using multiuser scenarios, is a critical part of Web application design and development, and needs to be considered as a part of the overall planning of the application. Performance testing is much more critical for server applications than for desktop applications, because managing simultaneous users places higher demands on the application.

Remember that using the Session object to store values increases the memory requirements of your application, and therefore decreases the number of concurrent users an application can support. When you build your application, the following three factors determine how much server memory your application will consume:

Concurrent Sessions The number of sessions that exist at any given moment is cumulative over the lifetime of the Session object. So, if you have a Session.Timeout value of 20 minutes, your concurrent sessions will be equal to the number of connections you expect to service over a 20-minute period.
Variables and Objects Per Session How many objects or variables are you storing? A few session settings are fine. Long lists of session-scope variables (especially if they are components) should be avoided. As the number of variables increases, the time it takes to retrieve them also increases.
Size of Each Variable or Object Stored Are you storing lengthy strings or large component objects? Store them for as long as necessary, and then free them—replace long strings with empty string and objects with Nothing (or Null).