On any social media platform when I search for users, I get results sorted by count of mutual connections (first degree connections)
Lets say I search for a user named "Rishi" As shown in attached image below Rishi Xyz was top suggestion as we had 10 mutual connections Followed by others descending
For full text searches we could always use elastic search, but how do we sort them on mutual connections
How would this scale for millions of users
Any relevant articles where I can study more about its implementation could help