fastapi: Background task not executed on high load

I have a simple function that inserts in the database (RethinkDB) a generated user. The functions looks like this:

` @router.get(‘/api/v1/create_load_testing_user’) async def create_load_testing_user(request: Request, background_tasks: BackgroundTasks):

    api_user_1 = copy.deepcopy(default_user_model)
    api_user_1["uid"] = get_uuid_number()
    api_user_1["profile"]["name"] = "API USER 1"
    api_user_1["login"]["client_id"] = get_uuid_number()
    api_user_1["login"]["client_secret"] = get_uuid_number()
    api_user_1["is_performance_test_user"] = True

background_tasks.add_task(
    login_test_performance_insert,
    api_user_1,
    request
)

return api_user_1


async def login_test_performance_insert(api_user_1, request):
    await r.table("users").insert(api_user_1).run(await get_rethink_conn(request))
    return True

`

Now, i am doing a performance test with AB: ab -n 8000 -c 1000 https://link

And i am getting: Complete requests: 8000 Failed requests: 6294 (Connect: 0, Receive: 0, Length: 6294, Exceptions: 0) Non-2xx responses: 1706

This means that i just lost 1706 user entries in the db

What am i doing wrong?

I have a http middleware that acquires a db connection, from a pool, before executing the route and releases it after the function is completed