postgresql PG::TRDeadlockDetected: 错误: 检测到死锁
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PG::TRDeadlockDetected: ERROR: deadlock detected
提问by Railsana
I am restarting 8 puma workers via bundle exec pumactl -F config/puma.rb phased-restartwhat works fine. Now I am getting more and more postgres errors:
我正在通过bundle exec pumactl -F config/puma.rb phased-restart正常工作的方式重新启动 8 名 puma 工人。现在我收到越来越多的 postgres 错误：
PG::TRDeadlockDetected: ERROR: deadlock detected
I found a about 50 of idle postgres processes running:
我发现大约有 50 个空闲的 postgres 进程在运行：
postgres: myapp myapp_production 127.0.0.1(59950) idle
postgres: myapp myapp_production 127.0.0.1(60141) idle
...
They disappear when I am running bundle exec pumactl -F config/puma.rb stop.
After starting the app with bundle exec pumactl -F config/puma.rb start, I get exactly 16 idle processes. (Eight too many in my opinion.)
当我跑步时它们消失了bundle exec pumactl -F config/puma.rb stop。使用 启动应用程序后bundle exec pumactl -F config/puma.rb start，我正好得到 16 个空闲进程。（我认为八个太多了。）
How can I manage these processes better? Thanks for your help!
如何更好地管理这些流程？谢谢你的帮助！
Update
更新
My puma.rb:
我的 puma.rb：
environment 'production'
daemonize true
pidfile 'tmp/pids/puma.pid'
state_path 'tmp/pids/puma.state'
threads 0, 1
bind 'tcp://0.0.0.0:3010'
workers 8
quiet
回答by Railsana
I might have found a solution to my question:I had some queries outside of my controllers (custom middleware), which seem to have caused the problem.
我可能已经找到了我的问题的解决方案：我在控制器（自定义中间件）之外进行了一些查询，这似乎导致了问题。
If you have queries outside of controllers (ActiveMailer could also cause this problem), put your code in a ActiveRecord::Base.connection_pool.with_connectionblock:
如果您在控制器之外有查询（ActiveMailer 也可能导致此问题），请将您的代码放在一个ActiveRecord::Base.connection_pool.with_connection块中：
ActiveRecord::Base.connection_pool.with_connection do
# code
end
ActiveRecord's with_connection method yields a database connection from its pool to the block. When the block finishes, the connection is automatically checked back into the pool, avoiding connection leaks.
ActiveRecord 的 with_connection 方法产生一个从它的池到块的数据库连接。当块完成时，连接会自动检回到池中，避免连接泄漏。
I hope this helps some of you!
我希望这对你们中的一些人有所帮助！
回答by getabetterpic
Looks like this may be due to the database connections not getting closed on server shutdown. https://github.com/puma/puma/issues/59A lot of people in that issue are using ActiveRecord:: ConnectionAdapters::ConnectionManagement to handle this, or you may be able to roll your own by using Puma's on_restarthook.
看起来这可能是由于数据库连接在服务器关闭时没有关闭。https://github.com/puma/puma/issues/59该问题中的很多人都在使用 ActiveRecord::ConnectionAdapters::ConnectionManagement 来处理这个问题，或者您可以使用 Puma 的on_restart钩子来推出自己的。
