Adobe ColdFusion 8 Web Application Construction Kit, Volume 1: Getting Started

Using Locks to Protect Against Race Conditions

ColdFusion is a multithreaded application, meaning that the server can process more than one page request at a time. Generally speaking, this is a wonderful feature. Because the server can in effect do more than one thing at a time, it can tend to two or three (or 50) simultaneous visitors to your application.

But as wonderful as multithreading is, it also means that you need to think carefully about situations where more than one person is accessing a particular page at the same time. Unless you take steps to prevent it, the two page requests can be reading or changing the same application variable at the very same moment. If you are using Application variables to track any type of data that changes ...