Drb和“被回收的对象” 例外

Question

我遇到了一个奇怪的问题。 我的控制器调用 drb 对象

@request_handler = DRbObject.new(nil, url)
availability_result = @request_handler.fetch_availability(request, @reservation_search, params[:selected_room_rates])

，并且该 Drb 对象正在进行一些搜索。

但有时，在 Linux 环境中，我会通过此堆栈跟踪得到“0xdba87b30 是回收对象”。

--- 
- (druby://10.254.143.159:9001) /usr/lib/ruby/1.8/drb/drb.rb:375:in `_id2ref'
- (druby://10.254.143.159:9001) /usr/lib/ruby/1.8/drb/drb.rb:375:in `to_obj'
- (druby://10.254.143.159:9001) /usr/lib/ruby/1.8/drb/drb.rb:1402:in `to_obj'
- (druby://10.254.143.159:9001) /usr/lib/ruby/1.8/drb/drb.rb:1704:in `to_obj'
- (druby://10.254.143.159:9001) /usr/lib/ruby/1.8/drb/drb.rb:613:in `recv_request'
- (druby://10.254.143.159:9001) /usr/lib/ruby/1.8/drb/drb.rb:911:in `recv_request'
- (druby://10.254.143.159:9001) /usr/lib/ruby/1.8/drb/drb.rb:1530:in `init_with_client'
- (druby://10.254.143.159:9001) /usr/lib/ruby/1.8/drb/drb.rb:1542:in `setup_message'
- (druby://10.254.143.159:9001) /usr/lib/ruby/1.8/drb/drb.rb:1494:in `perform'
- (druby://10.254.143.159:9001) /usr/lib/ruby/1.8/drb/drb.rb:1589:in `main_loop'
- (druby://10.254.143.159:9001) /usr/lib/ruby/1.8/drb/drb.rb:1585:in `loop'
- (druby://10.254.143.159:9001) /usr/lib/ruby/1.8/drb/drb.rb:1585:in `main_loop'
- (druby://10.254.143.159:9001) /usr/lib/ruby/1.8/drb/drb.rb:1581:in `start'
- (druby://10.254.143.159:9001) /usr/lib/ruby/1.8/drb/drb.rb:1581:in `main_loop'
- (druby://10.254.143.159:9001) /usr/lib/ruby/1.8/drb/drb.rb:1430:in `run'
- (druby://10.254.143.159:9001) /usr/lib/ruby/1.8/drb/drb.rb:1427:in `start'
- (druby://10.254.143.159:9001) /usr/lib/ruby/1.8/drb/drb.rb:1427:in `run'
- (druby://10.254.143.159:9001) /usr/lib/ruby/1.8/drb/drb.rb:1347:in `initialize'
- (druby://10.254.143.159:9001) /usr/lib/ruby/1.8/drb/drb.rb:1627:in `new'
- (druby://10.254.143.159:9001) /usr/lib/ruby/1.8/drb/drb.rb:1627:in `start_service'
- (druby://10.254.143.159:9001) ./core/request_handler.rb:244
- (druby://10.254.143.159:9001) /usr/local/lib/site_ruby/1.8/rubygems/custom_require.rb:27:in `gem_original_require'
- (druby://10.254.143.159:9001) /usr/local/lib/site_ruby/1.8/rubygems/custom_require.rb:27:in `require'
- (druby://10.254.143.159:9001) /usr/lib/ruby/gems/1.8/gems/activesupport-2.1.1/lib/active_support/dependencies.rb:510:in `require'
- (druby://10.254.143.159:9001) /usr/lib/ruby/gems/1.8/gems/activesupport-2.1.1/lib/active_support/dependencies.rb:355:in `new_constants_in'
- (druby://10.254.143.159:9001) /usr/lib/ruby/gems/1.8/gems/activesupport-2.1.1/lib/active_support/dependencies.rb:510:in `require'
- (druby://10.254.143.159:9001) core/request_handler.rb:31
- (druby://10.254.143.159:9001) core/request_handler.rb:29:in `each'
- (druby://10.254.143.159:9001) core/request_handler.rb:29
- app/drops/room_drop.rb:18:in `room_rates'
- lib/liquid/liquid_templates.rb:47:in `parse_template'
- lib/liquid/liquid_templates.rb:21:in `render_liquid_template_without_layout'
- app/helpers/skins_helper.rb:6:in `render_respond_by_format'
- app/helpers/skins_helper.rb:4:in `render_respond_by_format'
- app/helpers/skins_helper.rb:25:in `render_availability_action'
- app/controllers/web_reservations_controller.rb:109:in `availability_simplified'
- /usr/bin/mongrel_rails:19:in `load'
- /usr/bin/mongrel_rails:19

奇怪的是，我无法在我的（Windows）开发机器中重现该错误，但我只在我的 Linux 测试服务器中得到它（我的机器里有两个杂种，而不是一个）。

怎么了？ 我认为这是一个垃圾收集器问题（在重用之前收集对象），但我不明白我在哪里做错了。 我只是在控制器中创建对象并调用它的方法。

任何想法？

谢谢！ 罗伯托

Answer 1

该错误意味着您正在尝试提供已被垃圾收集的对象，这通常是因为该对象超出了服务器的范围。

最安全的选择是首先弄清楚为什么该对象会被过早地垃圾收集。 或者，您可以通过调用 GC.disable 来禁用服务器的 GC，这通常是一个坏主意，尤其是在您的服务器长时间运行的情况下。

Answer 2

有一种方法可以延迟服务器上传递给客户端的对象的垃圾回收：

  DRb.install_id_conv TimerIdConv.new 60 # one minute

请参阅https://ruby-doc.org/stdlib-2.5.3/libdoc/drb/rdoc/DRb/TimerIdConv.html

Answer 3

您是否有可能在服务器中多次调用 DRb.start_service ？