from pymongo import MongoClient
from pymongo.read_preferences import ReadPreference
from concurrent.futures import ThreadPoolExecutor, wait

client = MongoClient()
session = client.start_session()
read_preference = ReadPreference.PRIMARY


def test():
    for i in range(100):
        client._select_server(read_preference, session, "testOperation")



def test2_target():
    client._select_server(read_preference, session, "testOperation")


def test2():
    futures = []
    with ThreadPoolExecutor(max_workers=100) as pool:
        for i in range(100):
            futures.append(pool.submit(test2_target))
        wait(futures)
    

if __name__ == '__main__':
    import timeit
    print(timeit.timeit("test()", setup="from __main__ import test, client, read_preference, session", number=1000))
    print(timeit.timeit("test2()", setup="from __main__ import test2, client, read_preference, session", number=1000))