bad mongodb connection management

gistfile1.js

var dbClient;
var ensureDbClient = function(callback){
	if(dbClient){
		console.info('ensureDbClient: returning existing client');
		return callback(null, dbClient);
	} else {
		console.info('ensureDbClient: returning NEW client');
		MongoClient.connect(mongoConnectionString, mongoConnectionOptions, function(err, db){
			if(err){
				return callback(err, null);
			}
			dbClient = db;
			callback(null, dbClient);
		});	
	}
};

if I call this from within the same module, it's creating a new client each time

For example, if I call this in a loop, a gazillion connections are being created (until I ultimately run out of connections):

var saveItem = function(obj, callback){
    ensureDbClient(function(err, db){
        if(err) return callback(err, null);
        db.collection(organizationsCollection).insert(obj, {w:1}, callback);
    }); 
};

Do you mean you are calling saveItem over and over in a for loop?

yes - and as you mentioned on the phone, the culprit is likely that multiple invocations of this fcn have occurred before the initialization of the connection can happen. Modifying the module now to initialize the connection first...