How to find current connection pool size on heroku

Question

We have a rails 3.2(.11) app with many dynos running on the heroku bamboo stack, connecting to a MySQL RDS server. There seem to be some issues with our current database connect

Answer 1

This information is available via an interface in Rails https://github.com/rails/rails/blob/master/activerecord/lib/active_record/connection_handling.rb#L98-L106 it is in Rails 3+

ActiveRecord::Base.connection_config
# => {:adapter=>"postgresql", :encoding=>"utf8", :pool=>5, :host=>"localhost", :database=>"triage_development"}

You can use this to get the current pool size without needing to eval or relying on the existence of an unexposed instance variable however in rails 3 it may return nil if it hasn't been explicitly set

ActiveRecord::Base.connection_config[:pool]
# => 5