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我爲我的Rails應用程序運行4個Unicorn進程，他們吃掉了所有可用的MySQL連接，導致它崩潰，導致「連接太多」錯誤。今天我不得不重啓我的數據庫實例4次。 =（獨角獸吃掉MySQL連接不尊重池大小 - Rails
流程
$ ps ax | grep [u]ni 21618 ? Sl 0:15 unicorn master -D -c /home/deployer/apps/XXX/shared/config/unicorn.rb -E production 21632 ? Sl 0:20 unicorn worker[0] -D -c /home/deployer/apps/XXX/shared/config/unicorn.rb -E production 21636 ? Sl 0:14 unicorn worker[1] -D -c /home/deployer/apps/XXX/shared/config/unicorn.rb -E production 21640 ? Sl 0:20 unicorn worker[2] -D -c /home/deployer/apps/XXX/shared/config/unicorn.rb -E production 21645 ? Sl 0:12 unicorn worker[3] -D -c /home/deployer/apps/XXX/shared/config/unicorn.rb -E production
我的database.yml是建立在ActiveRecord的池22個連接...
...
production:
adapter: mysql2
encoding: utf8
database: xxx
username: xxx
password: xxx
host: xxx
port: 3306
pool: 22
...
而且獨角獸配置文件是這樣的：
working_directory "/home/deployer/apps/XXX/current"
pid "/home/deployer/apps/XXX/shared/pids/unicorn.pid"
stderr_path "/home/deployer/apps/XXX/shared/log/unicorn.log"
stdout_path "/home/deployer/apps/XXX/shared/log/unicorn.log"
listen "/tmp/unicorn.XXX.sock"
worker_processes 4
timeout 100
preload_app true
before_fork do |server, worker|
# Disconnect since the database connection will not carry over
if defined? ActiveRecord::Base
ActiveRecord::Base.connection.disconnect!
end
# Quit the old unicorn process
old_pid = "#{server.config[:pid]}.oldbin"
if File.exists?(old_pid) && server.pid != old_pid
begin
Process.kill("QUIT", File.read(old_pid).to_i)
rescue Errno::ENOENT, Errno::ESRCH
# someone else did our job for us
end
end
end
after_fork do |server, worker|
# Start up the database connection again in the worker
if defined?(ActiveRecord::Base)
ActiveRecord::Base.establish_connection
end
child_pid = server.config[:pid].sub(".pid", ".#{worker.nr}.pid")
system("echo #{Process.pid} > #{child_pid}")
end
如果我們查看數據庫控制檯，我們會看到類似這樣的內容。他們已經吃掉了大部分的連接。 （我除了獨角獸以外什麼都沒有運行）在我看來，應該有1個連接* 4個獨角獸= 4個連接。
mysql> show full processlist; +-----+----------+--------------------------------------------------+------------------------+---------+------+-------+-----------------------+ | Id | User | Host | db | Command | Time | State | Info | +-----+----------+--------------------------------------------------+------------------------+---------+------+-------+-----------------------+ | 2 | rdsadmin | localhost:31383 | NULL | Sleep | 9 | | NULL | | 52 | level | 212.100.140.42:50683 | leveltravel_production | Query | 0 | NULL | show full processlist | | 74 | level | ip-10-55-10-151.eu-west-1.compute.internal:38197 | leveltravel_production | Sleep | 5 | | NULL | | 75 | level | ip-10-55-10-151.eu-west-1.compute.internal:38199 | leveltravel_production | Sleep | 8 | | NULL | | 76 | level | ip-10-55-10-151.eu-west-1.compute.internal:38201 | leveltravel_production | Sleep | 8 | | NULL | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ CUT ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ | 157 | level | ip-10-55-10-151.eu-west-1.compute.internal:38321 | leveltravel_production | Sleep | 154 | | NULL | | 158 | level | ip-10-55-10-151.eu-west-1.compute.internal:38322 | leveltravel_production | Sleep | 17 | | NULL | | 159 | level | ip-10-55-10-151.eu-west-1.compute.internal:38325 | leveltravel_production | Sleep | 54 | | NULL | | 160 | level | ip-10-55-10-151.eu-west-1.compute.internal:38326 | leveltravel_production | Sleep | 54 | | NULL | | 161 | level | ip-10-55-10-151.eu-west-1.compute.internal:38327 | leveltravel_production | Sleep | 54 | | NULL | | 162 | level | ip-10-55-10-151.eu-west-1.compute.internal:38329 | leveltravel_production | Sleep | 42 | | NULL | +-----+----------+--------------------------------------------------+------------------------+---------+------+-------+-----------------------+ 90 rows in set (0.15 sec)
您也可以在sidekiq倉庫看看問題＃503對於這個問題https://github.com/mperham/sidekiq/issues/503