We needed the close_all_db function to close any remaining database connections on shutdown. But why were there any unclosed db connections anyway? The connections were closed after the thread was already marked as shut down so when exiting the thread wasn't done with closing the database yet and thus sometimes you had an improper shutdown. Now the threads are only marked as stopped when the database connection is also closed so we have guaranteed that they'll be closed when the server returns. So no more need to explicitly close any remaining afterwards.
