Connections not being closed [4.1.3]

[Rob Polak]

I am having some connection issues out to my replica set, the short of it is that we have WAY too many connections being opened and connections are not being closed.

As a test I created 500 connections out to our mongo instance and then ran the proper close statement:

process.on('SIGINT', function() {
  mongoose.connection.close(function () {
    console.log('Mongoose default connection disconnected through app termination');
    process.exit(0);
  });
});

However, 15 minutes later I still see those 500 connections even though the node process has been shut down entirely the whole time.

Any idea what might be causing these connections to linger around?  Basically I am having issues on the mongo side that is causing me to run out of physical memory.

Thanks 

Rob