Performance and ActiveRecord::Base.establish_connection

2008-01-07

I’ve got a library which requires its own database so I’m using a shared superclass for my models which uses establish_connection to point to a different database than the default one used by ActiveRecord::Base.connection.  The problem is performance.  I’m inserting and updating a large amount of data in a single unit test method and finding that when I use the customized connection, my performance goes from 20 seconds to 45 seconds!  If I change my library to use ActiveRecord::Base’s connection, the peformance returns to 20 seconds.  I’m using AR 2.0.1 with the mysql C driver on OSX.

Anyone know why using a custom connection would cause such a dramatic performance degradation?  My base class couldn’t be simpler:

    class ContextBase < ActiveRecord::Base

      self.abstract_class = true

      establish_connection "context_#{ENV['RAILS_ENV'] || 'development'}"

    end