Question

We’re using two databases, one main, and one secondary in a seperate model, like so:

class SecondModel < ActiveRecord::Base
  establish_connection(ENV['SECOND_DATABASE'])
end

I’m going to switch to Unicorn on a Heroku app, and we have to disconnect the database here:

before_fork do |server, worker|
  if defined?(ActiveRecord::Base)
    ActiveRecord::Base.connection.disconnect!
  end
end

I am not sure about closing the connection for the second database.
Does anybody have any thoughts on this?

Answer 1

Ok I think I got it working now, here is the code:

before_fork do |server, worker|
  if defined?(ActiveRecord::Base)
    # disconnect primary database
    ActiveRecord::Base.connection.disconnect!
    Rails.logger.info('Disconnected from ActiveRecord')

    # disconnect the second database
    SecondModel.connection.disconnect! if SecondModel.connection.active?
    Rails.logger.info('Disconnected from SecondModel')
  end
end

after_fork do |server, worker|
  if defined?(ActiveRecord::Base)
    # connect primary database
    ActiveRecord::Base.establish_connection
    Rails.logger.info('Connected to ActiveRecord')

    # connect second database
    SecondModel.establish_connection(ENV["SECOND_DATABASE"])
    Rails.logger.info('Connected to SecondModel')

    # verify connections
    ActiveRecord::Base.verify_active_connections!
  end
end

I’ve got some errors because I was verifying the connections before re-connection to the SecondModel’s database.

Any thoughts are welcome!