MySQL server has gone away fix - Ensure it only affects mysql2 adapter

connection_fix.rb

# If your workers are inactive for a long period of time, they'll lose
# their MySQL connection.
#
# This hack ensures we re-connect whenever a connection is
# lost. Because, really. why not?
#
# Stick this in RAILS_ROOT/config/initializers/connection_fix.rb (or somewhere similar)
#
# From:
#   http://coderrr.wordpress.com/2009/01/08/activerecord-threading-issues-and-resolutions/

adapter = ActiveRecord::Base.configurations[Rails.env]['adapter']

if adapter == "mysql2"
 module ActiveRecord::ConnectionAdapters
   class Mysql2Adapter
     alias_method :execute_without_retry, :execute

     def execute(*args)
       execute_without_retry(*args)
     rescue ActiveRecord::StatementInvalid => e
       if e.message =~ /server has gone away/i
         warn "Server timed out, retrying"
         reconnect!
         retry
       else
         raise e
       end
     end
   end
 end
end

This is a work around to make patch the code if the adapter is mysql2. Without the if statement this patch will fail if you use other database adapters in different environments.

Here's my article with full explanation
http://thirddirective.com/posts/19-mysql-server-has-gone-away-fix-only-affecting-mysql