def _tail_profile(self, db, interval):
        """Tails the system.profile collection"""
        latest_doc = None
        while latest_doc is None:
            time.sleep(interval)
            latest_doc = db['system.profile'].find_one()

        current_time = latest_doc['ts']

        while True:
            time.sleep(interval)
            cursor = db['system.profile'].find({'ts': {'$gte': current_time}}).sort('ts', pymongo.ASCENDING)
            for doc in cursor:
                current_time = doc['ts']
                yield doc
Tails the system.profile collection