> You can’t just limit the check to private subs because it’s not known if they are private or not at the time.
That's not necessarily true. Perhaps the status of subreddits is cached (because there's no reason to hit the DB 100 times/second to check if r/funny is private or public). But for a given request to a private sub, it would need to check each user.
That's not necessarily true. Perhaps the status of subreddits is cached (because there's no reason to hit the DB 100 times/second to check if r/funny is private or public). But for a given request to a private sub, it would need to check each user.