乘客併發連接錯誤

Question

我有生產服務器（Nginx + Passenger）。當我從另一臺計算機試圖ab -n 3 -c 3 myhost.ru/我在nginx的error.log中得到這個錯誤日誌：

[ pid=21160 thr=139775297914624 file=ext/nginx/HelperAgent.cpp:584 time=2011-08-31 15:25:49.22 ]: Uncaught exception in PassengerServer client thread: 
    exception: Cannot read response from backend process: Connection reset by peer (104) 
    backtrace: 
    in 'void Client::forwardResponse(Passenger::SessionPtr&, Passenger::FileDescriptor&, const Passenger::AnalyticsLogPtr&)' (HelperAgent.cpp:330) 
    in 'void Client::handleRequest(Passenger::FileDescriptor&)' (HelperAgent.cpp:510) 
    in 'void Client::threadMain()' (HelperAgent.cpp:603) 

[ pid=21249 thr=15884760 file=utils.rb:176 time=2011-08-31 15:25:49.022 ]: *** Exception PGError in application (server closed the connection unexpectedly 
    This probably means the server terminated abnormally 
    before or while processing the request. 
) (process 21249, thread #<Thread:0x00000001e4c3b0>): 
    from /home/deployer/yandex.ru/shared/bundle/ruby/1.9.1/gems/activerecord-3.1.0/lib/active_record/connection_adapters/postgresql_adapter.rb:276:in `exec' 
    from /home/deployer/yandex.ru/shared/bundle/ruby/1.9.1/gems/activerecord-3.1.0/lib/active_record/connection_adapters/postgresql_adapter.rb:276:in `block in clear_cache!' 
    from /home/deployer/yandex.ru/shared/bundle/ruby/1.9.1/gems/activerecord-3.1.0/lib/active_record/connection_adapters/postgresql_adapter.rb:275:in `each_value' 
    from /home/deployer/yandex.ru/shared/bundle/ruby/1.9.1/gems/activerecord-3.1.0/lib/active_record/connection_adapters/postgresql_adapter.rb:275:in `clear_cache!' 
    from /home/deployer/yandex.ru/shared/bundle/ruby/1.9.1/gems/activerecord-3.1.0/lib/active_record/connection_adapters/postgresql_adapter.rb:303:in `disconnect!' 
    from /home/deployer/yandex.ru/shared/bundle/ruby/1.9.1/gems/activerecord-3.1.0/lib/active_record/connection_adapters/abstract/connection_pool.rb:202:in `block in disconnect!' 
    from /home/deployer/yandex.ru/shared/bundle/ruby/1.9.1/gems/activerecord-3.1.0/lib/active_record/connection_adapters/abstract/connection_pool.rb:201:in `each' 
    from /home/deployer/yandex.ru/shared/bundle/ruby/1.9.1/gems/activerecord-3.1.0/lib/active_record/connection_adapters/abstract/connection_pool.rb:201:in `disconnect!' 
    from /home/deployer/yandex.ru/shared/bundle/ruby/1.9.1/gems/activesupport-3.1.0/lib/active_support/core_ext/module/synchronization.rb:35:in `block in disconnect_with_synchronization!' 
    from /home/deployer/.rvm/rubies/ruby-1.9.2-p180/lib/ruby/1.9.1/monitor.rb:201:in `mon_synchronize' 
    from /home/deployer/yandex.ru/shared/bundle/ruby/1.9.1/gems/activesupport-3.1.0/lib/active_support/core_ext/module/synchronization.rb:34:in `disconnect_with_synchronization!' 
    from /home/deployer/yandex.ru/shared/bundle/ruby/1.9.1/gems/activerecord-3.1.0/lib/active_record/connection_adapters/abstract/connection_pool.rb:395:in `block in clear_all_connections!' 
    from /home/deployer/yandex.ru/shared/bundle/ruby/1.9.1/gems/activerecord-3.1.0/lib/active_record/connection_adapters/abstract/connection_pool.rb:395:in `each_value' 
    from /home/deployer/yandex.ru/shared/bundle/ruby/1.9.1/gems/activerecord-3.1.0/lib/active_record/connection_adapters/abstract/connection_pool.rb:395:in `clear_all_connections!' 
    from /home/deployer/yandex.ru/shared/bundle/ruby/1.9.1/gems/activerecord-3.1.0/lib/active_record/connection_adapters/abstract/connection_specification.rb:123:in `clear_all_connections!' 
    from /home/deployer/.rvm/gems/ruby-1.9.2-p180/gems/passenger-3.0.7/lib/phusion_passenger/utils.rb:398:in `before_handling_requests' 
    from /home/deployer/.rvm/gems/ruby-1.9.2-p180/gems/passenger-3.0.7/lib/phusion_passenger/rack/application_spawner.rb:204:in `start_request_handler' 
    from /home/deployer/.rvm/gems/ruby-1.9.2-p180/gems/passenger-3.0.7/lib/phusion_passenger/rack/application_spawner.rb:170:in `block in handle_spawn_application' 
    from /home/deployer/.rvm/gems/ruby-1.9.2-p180/gems/passenger-3.0.7/lib/phusion_passenger/utils.rb:479:in `safe_fork' 
    from /home/deployer/.rvm/gems/ruby-1.9.2-p180/gems/passenger-3.0.7/lib/phusion_passenger/rack/application_spawner.rb:165:in `handle_spawn_application' 
    from /home/deployer/.rvm/gems/ruby-1.9.2-p180/gems/passenger-3.0.7/lib/phusion_passenger/abstract_server.rb:357:in `server_main_loop' 
    from /home/deployer/.rvm/gems/ruby-1.9.2-p180/gems/passenger-3.0.7/lib/phusion_passenger/abstract_server.rb:206:in `start_synchronously' 
    from /home/deployer/.rvm/gems/ruby-1.9.2-p180/gems/passenger-3.0.7/lib/phusion_passenger/abstract_server.rb:180:in `start' 
    from /home/deployer/.rvm/gems/ruby-1.9.2-p180/gems/passenger-3.0.7/lib/phusion_passenger/rack/application_spawner.rb:128:in `start' 
    from /home/deployer/.rvm/gems/ruby-1.9.2-p180/gems/passenger-3.0.7/lib/phusion_passenger/spawn_manager.rb:253:in `block (2 levels) in spawn_rack_application' 
    from /home/deployer/.rvm/gems/ruby-1.9.2-p180/gems/passenger-3.0.7/lib/phusion_passenger/abstract_server_collection.rb:132:in `lookup_or_add' 
    from /home/deployer/.rvm/gems/ruby-1.9.2-p180/gems/passenger-3.0.7/lib/phusion_passenger/spawn_manager.rb:246:in `block in spawn_rack_application' 
    from /home/deployer/.rvm/gems/ruby-1.9.2-p180/gems/passenger-3.0.7/lib/phusion_passenger/abstract_server_collection.rb:82:in `block in synchronize' 
    from <internal:prelude>:10:in `synchronize' 
    from /home/deployer/.rvm/gems/ruby-1.9.2-p180/gems/passenger-3.0.7/lib/phusion_passenger/abstract_server_collection.rb:79:in `synchronize' 
    from /home/deployer/.rvm/gems/ruby-1.9.2-p180/gems/passenger-3.0.7/lib/phusion_passenger/spawn_manager.rb:244:in `spawn_rack_application' 
    from /home/deployer/.rvm/gems/ruby-1.9.2-p180/gems/passenger-3.0.7/lib/phusion_passenger/spawn_manager.rb:137:in `spawn_application' 
    from /home/deployer/.rvm/gems/ruby-1.9.2-p180/gems/passenger-3.0.7/lib/phusion_passenger/spawn_manager.rb:275:in `handle_spawn_application' 
    from /home/deployer/.rvm/gems/ruby-1.9.2-p180/gems/passenger-3.0.7/lib/phusion_passenger/abstract_server.rb:357:in `server_main_loop' 
    from /home/deployer/.rvm/gems/ruby-1.9.2-p180/gems/passenger-3.0.7/lib/phusion_passenger/abstract_server.rb:206:in `start_synchronously' 
    from /home/deployer/.rvm/gems/ruby-1.9.2-p180/gems/passenger-3.0.7/helper-scripts/passenger-spawn-server:99:in `<main>' 
2011/08/31 15:25:49 [error] 21197#0: *41173 upstream prematurely closed connection while reading response header from upstream, client: 78.47.253.164, server: yandex.ru, request: "GET/HTTP/1.0", upstream: "passenger:unix:/passenger_helper_server:", host: "yandex.ru" 
[ pid=21160 thr=139775298115328 file=ext/nginx/HelperAgent.cpp:584 time=2011-08-31 15:25:49.31 ]: Uncaught exception in PassengerServer client thread: 
    exception: Cannot read response from backend process: Connection reset by peer (104) 
    backtrace: 
    in 'void Client::forwardResponse(Passenger::SessionPtr&, Passenger::FileDescriptor&, const Passenger::AnalyticsLogPtr&)' (HelperAgent.cpp:330) 
    in 'void Client::handleRequest(Passenger::FileDescriptor&)' (HelperAgent.cpp:510) 
    in 'void Client::threadMain()' (HelperAgent.cpp:603) 

2011/08/31 15:25:49 [error] 21197#0: *41172 upstream prematurely closed connection while reading response header from upstream, client: 78.47.253.164, server: yandex.ru, request: "GET/HTTP/1.0", upstream: "passenger:unix:/passenger_helper_server:", host: "yandex.ru" 
[ pid=21257 thr=15884760 file=utils.rb:176 time=2011-08-31 15:25:49.032 ]: *** Exception PGError in application (server closed the connection unexpectedly 
    This probably means the server terminated abnormally 
    before or while processing the request. 
) (process 21257, thread #<Thread:0x00000001e4c3b0>): 
    from /home/deployer/yandex.ru/shared/bundle/ruby/1.9.1/gems/activerecord-3.1.0/lib/active_record/connection_adapters/postgresql_adapter.rb:276:in `exec' 
    from /home/deployer/yandex.ru/shared/bundle/ruby/1.9.1/gems/activerecord-3.1.0/lib/active_record/connection_adapters/postgresql_adapter.rb:276:in `block in clear_cache!' 
    from /home/deployer/yandex.ru/shared/bundle/ruby/1.9.1/gems/activerecord-3.1.0/lib/active_record/connection_adapters/postgresql_adapter.rb:275:in `each_value' 
    from /home/deployer/yandex.ru/shared/bundle/ruby/1.9.1/gems/activerecord-3.1.0/lib/active_record/connection_adapters/postgresql_adapter.rb:275:in `clear_cache!' 
    from /home/deployer/yandex.ru/shared/bundle/ruby/1.9.1/gems/activerecord-3.1.0/lib/active_record/connection_adapters/postgresql_adapter.rb:303:in `disconnect!' 
    from /home/deployer/yandex.ru/shared/bundle/ruby/1.9.1/gems/activerecord-3.1.0/lib/active_record/connection_adapters/abstract/connection_pool.rb:202:in `block in disconnect!' 
    from /home/deployer/yandex.ru/shared/bundle/ruby/1.9.1/gems/activerecord-3.1.0/lib/active_record/connection_adapters/abstract/connection_pool.rb:201:in `each' 
    from /home/deployer/yandex.ru/shared/bundle/ruby/1.9.1/gems/activerecord-3.1.0/lib/active_record/connection_adapters/abstract/connection_pool.rb:201:in `disconnect!' 
    from /home/deployer/yandex.ru/shared/bundle/ruby/1.9.1/gems/activesupport-3.1.0/lib/active_support/core_ext/module/synchronization.rb:35:in `block in disconnect_with_synchronization!' 
    from /home/deployer/.rvm/rubies/ruby-1.9.2-p180/lib/ruby/1.9.1/monitor.rb:201:in `mon_synchronize' 
    from /home/deployer/yandex.ru/shared/bundle/ruby/1.9.1/gems/activesupport-3.1.0/lib/active_support/core_ext/module/synchronization.rb:34:in `disconnect_with_synchronization!' 
    from /home/deployer/yandex.ru/shared/bundle/ruby/1.9.1/gems/activerecord-3.1.0/lib/active_record/connection_adapters/abstract/connection_pool.rb:395:in `block in clear_all_connections!' 
    from /home/deployer/yandex.ru/shared/bundle/ruby/1.9.1/gems/activerecord-3.1.0/lib/active_record/connection_adapters/abstract/connection_pool.rb:395:in `each_value' 
    from /home/deployer/yandex.ru/shared/bundle/ruby/1.9.1/gems/activerecord-3.1.0/lib/active_record/connection_adapters/abstract/connection_pool.rb:395:in `clear_all_connections!' 
    from /home/deployer/yandex.ru/shared/bundle/ruby/1.9.1/gems/activerecord-3.1.0/lib/active_record/connection_adapters/abstract/connection_specification.rb:123:in `clear_all_connections!' 
    from /home/deployer/.rvm/gems/ruby-1.9.2-p180/gems/passenger-3.0.7/lib/phusion_passenger/utils.rb:398:in `before_handling_requests' 
    from /home/deployer/.rvm/gems/ruby-1.9.2-p180/gems/passenger-3.0.7/lib/phusion_passenger/rack/application_spawner.rb:204:in `start_request_handler' 
    from /home/deployer/.rvm/gems/ruby-1.9.2-p180/gems/passenger-3.0.7/lib/phusion_passenger/rack/application_spawner.rb:170:in `block in handle_spawn_application' 
    from /home/deployer/.rvm/gems/ruby-1.9.2-p180/gems/passenger-3.0.7/lib/phusion_passenger/utils.rb:479:in `safe_fork' 
    from /home/deployer/.rvm/gems/ruby-1.9.2-p180/gems/passenger-3.0.7/lib/phusion_passenger/rack/application_spawner.rb:165:in `handle_spawn_application' 
    from /home/deployer/.rvm/gems/ruby-1.9.2-p180/gems/passenger-3.0.7/lib/phusion_passenger/abstract_server.rb:357:in `server_main_loop' 
    from /home/deployer/.rvm/gems/ruby-1.9.2-p180/gems/passenger-3.0.7/lib/phusion_passenger/abstract_server.rb:206:in `start_synchronously' 
    from /home/deployer/.rvm/gems/ruby-1.9.2-p180/gems/passenger-3.0.7/lib/phusion_passenger/abstract_server.rb:180:in `start' 
    from /home/deployer/.rvm/gems/ruby-1.9.2-p180/gems/passenger-3.0.7/lib/phusion_passenger/rack/application_spawner.rb:128:in `start' 
    from /home/deployer/.rvm/gems/ruby-1.9.2-p180/gems/passenger-3.0.7/lib/phusion_passenger/spawn_manager.rb:253:in `block (2 levels) in spawn_rack_application' 
    from /home/deployer/.rvm/gems/ruby-1.9.2-p180/gems/passenger-3.0.7/lib/phusion_passenger/abstract_server_collection.rb:132:in `lookup_or_add' 
    from /home/deployer/.rvm/gems/ruby-1.9.2-p180/gems/passenger-3.0.7/lib/phusion_passenger/spawn_manager.rb:246:in `block in spawn_rack_application' 
    from /home/deployer/.rvm/gems/ruby-1.9.2-p180/gems/passenger-3.0.7/lib/phusion_passenger/abstract_server_collection.rb:82:in `block in synchronize' 
    from <internal:prelude>:10:in `synchronize' 
    from /home/deployer/.rvm/gems/ruby-1.9.2-p180/gems/passenger-3.0.7/lib/phusion_passenger/abstract_server_collection.rb:79:in `synchronize' 
    from /home/deployer/.rvm/gems/ruby-1.9.2-p180/gems/passenger-3.0.7/lib/phusion_passenger/spawn_manager.rb:244:in `spawn_rack_application' 
    from /home/deployer/.rvm/gems/ruby-1.9.2-p180/gems/passenger-3.0.7/lib/phusion_passenger/spawn_manager.rb:137:in `spawn_application' 
    from /home/deployer/.rvm/gems/ruby-1.9.2-p180/gems/passenger-3.0.7/lib/phusion_passenger/spawn_manager.rb:275:in `handle_spawn_application' 
    from /home/deployer/.rvm/gems/ruby-1.9.2-p180/gems/passenger-3.0.7/lib/phusion_passenger/abstract_server.rb:357:in `server_main_loop' 
    from /home/deployer/.rvm/gems/ruby-1.9.2-p180/gems/passenger-3.0.7/lib/phusion_passenger/abstract_server.rb:206:in `start_synchronously' 
    from /home/deployer/.rvm/gems/ruby-1.9.2-p180/gems/passenger-3.0.7/helper-scripts/passenger-spawn-server:99:in `<main>' 

Answer 1

我自己找到解決方案。有passenger_spawn_method conservative必須寫在nginx.conf而不是默認passenger_spawn_method conservative smart-lv2。

Answer 2

你分配或管理自己的數據庫連接/池？

Passenger在分叉後爲每個後臺工作人員重新連接默認的ActiveRecord數據庫池。

但是，其他資源或手動管理的數據庫連接需要在分派後爲每個工作人員手動設置/重新連接。

我寫了一個詳細的博客文章，解釋如何解決此問題：http://blog.winfieldpeterson.com/2011/01/06/passenger-resource-collision/

這聽起來像您遇到，多工人試圖共享一個數據庫連接和生產負荷下的錯誤是由於資源爭什麼。

Answer 3

我們對Rails 3.1，pg，ruby 1.9.3以及使用Apache + Passenger 3.0.9都有同樣的問題。升級到Rails 3.1.1似乎可以解決這個問題。

https://github.com/rails/rails/issues/1339