When exactly is the database loaded?

[eluser]jwindhorst[/eluser]
Maybe I'm asking the wrong question. I want users to be able to customize settings like LOGO_IMAGE_PATH, and then save that path in the DB. I want to be able to access this path always, globally, without hitting the DB in every controller/view, and I don't want it to be a constant that would require the user to edit a file.

Hope that is more clear.