ColdFusion Session Variables
The session variable is the scope of all connections for a single client to the ColdFusion Server application. A ColdFusion application allocates a distinctive thread of sessions for each individual client simultaneously using the application. The sessions have a limited time to live, meaning that if a single client is idle for 20 minutes, the session for that specific user will expire and all the allocated sets of session variables would deleted. 20 minutes is the default time a session can live; a programmer can override this default time in the application. The need for session variables in a web-server application is of course for preventing deadlock and resource availability, especially memory leaks. The fact that the server cannot determine if a user is finished with an application the sessions variable is used to de-allocate memory reserved for the client who has remained idle for a given time set in the sessions variables.