Variables stored in application state are global only to the particular process the application is running in, and each application process can have different values. Therefore, you cannot rely on application state to store unique values.
Global data that is stored in application state is volatile, it will be lost if the Web server process containing it is destroyed, such as from a server crash, upgrade, or shutdown.
Application state requires server memory, which can affect the performance of the server as well as the scalability of the application.
