What is the best way to store data received from the API in a contact?

Question

PHP

Hey! I'm doing a search in my database for the existence of users in it who have registered from under the contact.
A request is made to the contact API, returning the user's friends by the given id. Everything is good here. But then I need to query all friends of each friend. Here it turns out a monstrous volume of data and cycles.
I thought when registering a user, immediately enter the list of his friends into a file, and then extract it from the file. I heard that they do such things with redis.
Please tell me the best way to do this. As a result, when searching for friends and friends of friends, you need to check for their existence in the system.

Answer 1

It is better to use graph DBMS - they are just created for such cases. For example, ArangoDB

A distributed free and open-source database with a flexible data model for documents , graphs , and key-values ​​. Build high performance applications using a convenient SQL-like query language or JavaScript extensions.

and others.