EDIT: As bellwether pointed out, in MongoDb, loading a collection only means something roughly similar to "pre-allocating the connection and meta-information":

EDIT: As bellwether pointed out, in MongoDb, loading a collection only means something roughly similar to "pre-allocating the connection and meta-information": when querying a collection, no "actual" data is transmitted from server to client. As strange as it may sound...there's no need to update them (or my apps have been lucking it out for the last six months?). When you use less than 20 collections, this is not the kind of thing that'll become a "waste of ram". You could try a LRU to remove unused collections and get them later...but you would still lose more RAM because of the LRU manager...