# File lib/innodb/space.rb, line 383
  def each_doublewrite_page_number
    return nil unless system_space?

    unless block_given?
      return enum_for(:each_doublewrite_page_number)
    end

    trx_sys.doublewrite[:page_info][0][:page_number].each do |start_page|
      (start_page...(start_page+pages_per_extent)).each do |page_number|
        yield page_number
      end
    end
  end