I am building an APP where users generate content, which is feed to other users. Users also have the option to block users and / or content.
I need to know how to model this system that can scale.
Let’s suppose an extreme example where a user has blocked over 1 million other users.
Each time my server has to generate the list of content to return to this user, the query would have to check with this user’s array of 1 million items to check if the recommended content is blocked or not.
How do modern web APPs solve this problem? I cannot think of any way scale when we consider these extreme examples.