mongoengine does not disconnect tcp auto, make client timeout

Today morning, I found I can not connect mongo anymore, and did a log of research for it.

I checked my system [windows], cause there is a blog say windows does not have two key in reg-table. [NOT WORK]

I try to call the disconnect function explicitly. [NOTWORK]

So, I tail the mongodb log under server.

I found that mongoengine establish connection twice when I call connect and doc.objects.filter(...) method.

def test_mongo_to_df():
    try:
        register_connection("default", config['MONGO_DB'], host=config['MONGO_URL'],
                            authentication_source=config['MONGO_AUTHENTICATION_SOURCE'])
        data = Record.objects.filter(dt__gt=datetime.now() - rd(minutes=1)).first()
        print(mongo_to_df(data))
    except KeyboardInterrupt as e:
        disconnect()
    else:
        disconnect()

It blocked.

Cause one of the connect client is never be released.

So, I try to use pymongo.MongoClient

def test_pymongo():
    myclient = pymongo.MongoClient("mongodb://wFGZp2q8hnxFlaXJ:4xlQxtV6jwrZ9ZiF@favormylikes.com:27017/")
    try:
        mydb = myclient["mydb"]
        mycol = mydb["record"]
        start = datetime.now() - rd(minutes=60)
        cursor = mycol.aggregate([{"$match": {"dt": {"$gte": start, "$lte": datetime.now()}}},
                                  {"$project": {"_id": 0,
                                                "src": "$src"}}])
        data = Df(list(cursor))
        print(data)
    except:
        myclient.close()
    else:
        myclient.close()

It work, maybe that is the reason why mongoengine always block.

Start by reproducing the reported register_connection, Record.objects.filter(...), and disconnect() sequence, then compare its connection lifecycle with the shown pymongo.MongoClient example. The issue is done when the MongoEngine query no longer blocks because its connection is released or disconnected as expected.