Instrument ActiveRecord and push the results to Statsd

gistfile1.rb

SQL_PARSER_REGEXP = /^(\w+)\s(\w+)\s\W*(\w+)/

ActiveSupport::Notifications.subscribe "sql.active_record" do |name, start, finish, id, payload|
  if payload[:name] == "SQL"
    if Thread.current[:stats_context] # where I store the name of the request context
      payload[:sql] =~ SQL_PARSER_REGEXP  # $1 will be the query type, $3 the table
      Statsd.timing("#{Thread.current[:stats_context]}.sql.#{$3}.#{$1}.query_time",
                        (finish - start) * 1000, 1)
    end
  end
end

To be a bit more precise, in the AR version I'm using, the code above will only get you inserts and deletes. payload[:name] will be "ModelName Load" for some selects and updates and counts don't seem to set a payload name. You therefore need to write some basic parser code to capture inserts, selects, updates and deletes.