Actioncable：Puma發現了這個錯誤：無法在5.000秒內從池中獲得連接

Question

我在本地（C9.io，尚未嘗試過）上收到此特定錯誤。這發生在很多用戶正在使用我的聊天對話時發生。

此外，我注意到，當我在平臺上工作了一段時間時... CPU級別的天空火箭。什麼會導致這種情況？

Puma caught this error: could not obtain a connection from the pool within 5.000 seconds (waited 5.022 seconds); all pooled connections were in use (ActiveRecord::ConnectionTimeoutError) 
/usr/local/rvm/gems/ruby-2.3.0/gems/activerecord-5.0.0.1/lib/active_record/connection_adapters/abstract/connection_pool.rb:202:in `block in wait_poll' 
/usr/local/rvm/gems/ruby-2.3.0/gems/activerecord-5.0.0.1/lib/active_record/connection_adapters/abstract/connection_pool.rb:193:in `loop' 
/usr/local/rvm/gems/ruby-2.3.0/gems/activerecord-5.0.0.1/lib/active_record/connection_adapters/abstract/connection_pool.rb:193:in `wait_poll' 
/usr/local/rvm/gems/ruby-2.3.0/gems/activerecord-5.0.0.1/lib/active_record/connection_adapters/abstract/connection_pool.rb:154:in `internal_poll' 
/usr/local/rvm/gems/ruby-2.3.0/gems/activerecord-5.0.0.1/lib/active_record/connection_adapters/abstract/connection_pool.rb:278:in `internal_poll' 
/usr/local/rvm/gems/ruby-2.3.0/gems/activerecord-5.0.0.1/lib/active_record/connection_adapters/abstract/connection_pool.rb:148:in `block in poll' 
/usr/local/rvm/rubies/ruby-2.3.0/lib/ruby/2.3.0/monitor.rb:214:in `mon_synchronize' 
/usr/local/rvm/gems/ruby-2.3.0/gems/activerecord-5.0.0.1/lib/active_record/connection_adapters/abstract/connection_pool.rb:158:in `synchronize' 
/usr/local/rvm/gems/ruby-2.3.0/gems/activerecord-5.0.0.1/lib/active_record/connection_adapters/abstract/connection_pool.rb:148:in `poll' 
/usr/local/rvm/gems/ruby-2.3.0/gems/activerecord-5.0.0.1/lib/active_record/connection_adapters/abstract/connection_pool.rb:709:in `acquire_connection' 
/usr/local/rvm/gems/ruby-2.3.0/gems/activerecord-5.0.0.1/lib/active_record/connection_adapters/abstract/connection_pool.rb:501:in `checkout' 
/usr/local/rvm/gems/ruby-2.3.0/gems/activerecord-5.0.0.1/lib/active_record/connection_adapters/abstract/connection_pool.rb:364:in `connection' 
/usr/local/rvm/gems/ruby-2.3.0/gems/activerecord-5.0.0.1/lib/active_record/connection_adapters/abstract/connection_pool.rb:875:in `retrieve_connection' 
/usr/local/rvm/gems/ruby-2.3.0/gems/activerecord-5.0.0.1/lib/active_record/connection_handling.rb:128:in `retrieve_connection' 
/usr/local/rvm/gems/ruby-2.3.0/gems/activerecord-5.0.0.1/lib/active_record/connection_handling.rb:91:in `connection' 
/usr/local/rvm/gems/ruby-2.3.0/gems/activerecord-5.0.0.1/lib/active_record/query_cache.rb:27:in `run' 
/usr/local/rvm/gems/ruby-2.3.0/gems/activesupport-5.0.0.1/lib/active_support/execution_wrapper.rb:39:in `block in register_hook' 
/usr/local/rvm/gems/ruby-2.3.0/gems/activesupport-5.0.0.1/lib/active_support/callbacks.rb:396:in `instance_exec' 
/usr/local/rvm/gems/ruby-2.3.0/gems/activesupport-5.0.0.1/lib/active_support/callbacks.rb:396:in `block in make_lambda' 
/usr/local/rvm/gems/ruby-2.3.0/gems/activesupport-5.0.0.1/lib/active_support/callbacks.rb:169:in `block (2 levels) in halting' 
/usr/local/rvm/gems/ruby-2.3.0/gems/activesupport-5.0.0.1/lib/active_support/callbacks.rb:547:in `block (2 levels) in default_terminator' 
/usr/local/rvm/gems/ruby-2.3.0/gems/activesupport-5.0.0.1/lib/active_support/callbacks.rb:546:in `catch' 
/usr/local/rvm/gems/ruby-2.3.0/gems/activesupport-5.0.0.1/lib/active_support/callbacks.rb:546:in `block in default_terminator' 
/usr/local/rvm/gems/ruby-2.3.0/gems/activesupport-5.0.0.1/lib/active_support/callbacks.rb:170:in `block in halting' 
/usr/local/rvm/gems/ruby-2.3.0/gems/activesupport-5.0.0.1/lib/active_support/callbacks.rb:454:in `block in call' 
/usr/local/rvm/gems/ruby-2.3.0/gems/activesupport-5.0.0.1/lib/active_support/callbacks.rb:454:in `each' 
/usr/local/rvm/gems/ruby-2.3.0/gems/activesupport-5.0.0.1/lib/active_support/callbacks.rb:454:in `call' 
/usr/local/rvm/gems/ruby-2.3.0/gems/activesupport-5.0.0.1/lib/active_support/callbacks.rb:101:in `__run_callbacks__' 
/usr/local/rvm/gems/ruby-2.3.0/gems/activesupport-5.0.0.1/lib/active_support/callbacks.rb:750:in `_run_run_callbacks' 
/usr/local/rvm/gems/ruby-2.3.0/gems/activesupport-5.0.0.1/lib/active_support/callbacks.rb:90:in `run_callbacks' 
/usr/local/rvm/gems/ruby-2.3.0/gems/activesupport-5.0.0.1/lib/active_support/execution_wrapper.rb:99:in `run!' 
/usr/local/rvm/gems/ruby-2.3.0/gems/activesupport-5.0.0.1/lib/active_support/execution_wrapper.rb:61:in `block in run!' 
/usr/local/rvm/gems/ruby-2.3.0/gems/activesupport-5.0.0.1/lib/active_support/execution_wrapper.rb:58:in `tap' 
/usr/local/rvm/gems/ruby-2.3.0/gems/activesupport-5.0.0.1/lib/active_support/execution_wrapper.rb:58:in `run!' 
/usr/local/rvm/gems/ruby-2.3.0/gems/actionpack-5.0.0.1/lib/action_dispatch/middleware/executor.rb:10:in `call' 
/usr/local/rvm/gems/ruby-2.3.0/gems/actionpack-5.0.0.1/lib/action_dispatch/middleware/static.rb:136:in `call' 
/usr/local/rvm/gems/ruby-2.3.0/gems/rack-cors-0.4.0/lib/rack/cors.rb:80:in `call' 
/usr/local/rvm/gems/ruby-2.3.0/gems/rack-2.0.1/lib/rack/sendfile.rb:111:in `call' 
/usr/local/rvm/gems/ruby-2.3.0/gems/railties-5.0.0.1/lib/rails/engine.rb:522:in `call' 
/usr/local/rvm/gems/ruby-2.3.0/gems/rack-cors-0.4.0/lib/rack/cors.rb:80:in `call' 
/usr/local/rvm/gems/ruby-2.3.0/gems/puma-3.6.0/lib/puma/configuration.rb:225:in `call' 
/usr/local/rvm/gems/ruby-2.3.0/gems/puma-3.6.0/lib/puma/server.rb:578:in `handle_request' 
/usr/local/rvm/gems/ruby-2.3.0/gems/puma-3.6.0/lib/puma/server.rb:415:in `process_client' 
/usr/local/rvm/gems/ruby-2.3.0/gems/puma-3.6.0/lib/puma/server.rb:275:in `block in run' 
/usr/local/rvm/gems/ruby-2.3.0/gems/puma-3.6.0/lib/puma/thread_pool.rb:116:in `block in spawn_thread' 

Answer 1

這看起來像一個縮放問題。嘗試按照this stackoverflow post中的建議增加ActiveRecord池大小。

至於CPU使用率。幾乎沒有辦法確定沒有看到代碼。即便如此，這將是困難的。嘗試像NewRelic這樣的監視工具來查看CPU密集型部件的位置。