How to work with several MySQL servers from under Node.JS at the same time?

Question

MySQL

Good afternoon.
There is a mobile project. Social network. All data is stored in MySQL, divided into logical shards. We store "hot data" in Redis, we also store the MySQL shard map there.
The back-end is written in node.js (express)
Interested in how you can quickly access different MySQL servers as part of processing one request to the back-end?
I'll give you an example.
The client accesses the back-end with a request for a user profile with id = 1, which we store on the mysql-1 server in shard #1. At the same moment, another client accesses the back-end with a request for a user profile with id = 2, which is stored on another server - mysql-2 in shard #2.
The number of mysql servers will grow. And the number of requests to the back-end will grow. Initializing a new connection to MySQL for each request to the back-end is probably not the best task.

Answer 1

Perhaps a stupid question: why not create separate connections to each server/shard at application startup?

Answer 2

Look in the direction of the connection pool, to raise the connection every time, a rather expensive operation.