database connection pooling in ruby

Question

I just started with Ruby and I am playing with Sinatra, but could not find a way to share database connections between requests.

I came from Java web developement and one of the basic things you have to do is to pool the database connections, so I am sure that something similar exists in Ruby, but I just can't find it.

ActiveRecord and DataMapper offer this feature but I don't need ORM and just want to make regular SQL queries.

Is there some specific approach for Sinatra or there are general ways for all Rack-based applications?

Answer 1

To persist a connection, you need only create an instance variable (Sinatra Applications are just objects anyway) or a global variable. Or a class that manages connections for you. Most Ruby database libraries I've seen are Database Adapters or just clients.

@db = Mysql2::Client.new #...

Or a global variable:

$db = Mysql2::Client.new #...

Connection pooling is just a way to share a small number of connections across multiple threads/fibers for the lifespan of the application. Java, the JVM, as far as I know doesn't share connections between processes.

However, there is a general purpose Connection Pool library for Ruby .