Is there a performance penalty for storing values in the web.config compared to const fields?

Question

Hello, currently in our application we have an ApplicationConfiguration class. It is basically just a static class with const values specifying certain application-global configuration options. Some of these values will rarely if ever change and are only put into the configuration for elegance/cleanness.

Some of these values though do need to be different between production and development. So I'm considering making this class just a wrapper over Web.config. These values are checked many times throughout our codebase. If I change these from a const to a read-only getter that reads from Web.config will this affect compiler optimizations or make our application in any way slower?

Answer 1

Web.config values are read into memory once in app start, and are held there until the app ends. So, there's no real difference in performance here -- no extra file I/O repeatedly reading web.config.

One key difference between the two approaches happens when you need to change the value of one of the configuration options. Changing the value in web.config is relatively easy and may not even require a restart of the application (depends upon how it's configured).

To change the value of a constant, of course, you have to recompile and redeploy your code. That may not be a trivial endeavor.