[dancer-users] Dancer calling database connection

the Dancer advent calendar says that: Use Starman's --preload-app option to enable this (but be aware that this can cause Bad Things to happen if resources like database connections or other sockets are opened by your app at compile time, as they will be unintentionally shared amongst child processes. what is actually meant by that? when a url is requested my route is calling the model which opens a database connection, does sql and closes the connection. So this is done at runtime. when would calling database connection at compile time then ?also calling connect_cached would cause any problems under a preforked server like starman?