IOS app will send from time to time coordinates to server through REST api. On server inside DB registered users are stored with their coordinates. Each user may have many friends which he want to track if they are close to him. So server after each coordinate update (from user) has to check if his friends are close to him (with a radius also stored in DB per user). It has to handle MANY users.
So many writes to DB all the time and after each write there is computation of friends that are nearby.
As a server technology I would like to use node.js, but I am wondering about which (or what type od DB) use? Are there any databases which will help with all geolocation calculations or are specialy "tweaked" for such computation?
What would you recommend?
MongoDB has geospatial indexes and is pretty common in the node.js world. It has a few query types that are useful when working with geo data.