我在本地工作时遇到这个特定的错误（C9.io，尚未尝试过）。当许多用户使用我的聊天对话时会发生这种情况。
另外，我注意到，当我在平台上工作一段时间...... CPU级天空火箭。是什么导致这个？
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'
答案 0 :(得分：1)
这看起来像是一个扩展问题。尝试按照this stackoverflow post中的建议增加ActiveRecord池大小。
至于CPU使用率。几乎没有办法确定没有看到代码。即便如此，这也很困难。尝试使用NewRelic等监视工具来查看CPU密集型部件的位置。