title: Pymongo code that can loop through with speed a very large number of account on website page that requires username and password for registration?
body: <p>I was wonder what if i had more than 1 million users, how much time will take it to loop every account to check for the username and email if the registration page to check if they are already used or not, or check if the username and password and correct in the log in page, won't it take ages if i do it in a traditional for loop?</p>