Heroku Sidekiq：ActiveRecord :: StatementInvalid：PG :: UnableToSend：SSL SYSCALL错误：检测到EOF

嗨，我们正在使用独角兽和Sidekiq在Heroku的雪松堆栈上运行。我们间歇地得到以下错误

BurnThis ActiveRecord::StatementInvalid: PG::UnableToSend: SSL SYSCALL error: EOF detected

ActiveRecord::StatementInvalid: PG::ConnectionBad: PQconsumeInput() SSL SYSCALL error: Connection timed out

有没有人有任何洞察这些错误的直接原因？是否有太多的连接到我们的数据库？我们已经通过以下方式设置了我们的分岔：

unicorn.rb

worker_processes Integer(ENV["WEB_CONCURRENCY"] || 3)
timeout 30
preload_app true

before_fork do |server, worker|
  Signal.trap 'TERM' do
    puts 'Unicorn master intercepting TERM and sending myself QUIT instead'
    Process.kill 'QUIT', Process.pid
  end

  defined?(ActiveRecord::Base) and
    ActiveRecord::

Base.connection.disconnect!
end

after_fork do |server, worker|
  Signal.trap 'TERM' do
    puts 'Unicorn worker intercepting TERM and doing nothing. Wait for master to send QUIT'
  end

  # other setup
  if defined?(ActiveRecord::Base)
    config = Rails.application.config.database_configuration[Rails.env]
    config['adapter'] = 'postgis'
    config['pool']              = ENV['DB_POOL'] || 5
    config['reaping_frequency'] = ENV['DB_REAP_FREQ'] || 10 # seconds
    ActiveRecord::Base.establish_connection(config)
  end
end

和sidekiq.rb

Sidekiq.configure_server do |config|
  config.redis = { :url => ENV['REDIS_URL'], :namespace => 'btsidekiq' }

  if defined?(ActiveRecord::Base)
    config = Rails.application.config.database_configuration[Rails.env]
    config['adapter'] = 'postgis'
    config['pool']              = ENV['DB_POOL'] || 5
    config['reaping_frequency'] = ENV['DB_REAP_FREQ'] || 10 # seconds
    ActiveRecord::Base.establish_connection(config)
  end
end

Sidekiq.configure_client do |config|
  config.redis = { :url => ENV['REDIS_URL'], :namespace => 'btsidekiq' }
end

我们的数据库池大小很大DB_POOL = 100，我们在一个PG数据库上，显然同时支持500个连接。

此错误是由您的postgis适配器尝试使用来自ActiveRecord连接池的陈旧/死亡连接引起的。解决这个问题有两种方法：

>连接池大小匹配线程数/进程数
>降低连接收获频率(收费者检查死区连接池，每N秒)

要实现#1，您需要设置适合独角兽和Sidekiq的池大小，这可能有不同的需求。

Unicorn是单线程的，因此每个进程的默认池大小为5个连接是正确的。每个WEB_CONCURRENCY后端独角兽员工最多可以分配5个连接。您应该重置默认池大小，并使用您现有的unicorn.rb：

$> heroku config:set DB_POOL=5

Sidekiq使用了一个非常不同的模型。默认情况下，Sidekiq有一个进程和N个线程。你想要一个比Sidekiq线程数更大的DB池大小。您可以在config / initializers / sidekiq.rb中实现这一点，如下所示：

Sidekiq.configure_server do |config|
  pool_size = Sidekiq.options[:concurrency] + 2

  config.redis = { :url => ENV['REDIS_URL'], :namespace => 'btsidekiq', :size => pool_size }

  if defined?(ActiveRecord::Base)
    config = Rails.application.config.database_configuration[Rails.env]
    config['adapter'] = 'postgis'
    config['pool']              = pool_size
    config['reaping_frequency'] = ENV['DB_REAP_FREQ'] || 10 # seconds
    ActiveRecord::Base.establish_connection(config)
  end
end

我最好的猜测是，使用这么大的100连接池，你更有可能产生死连接。适当调整池的大小应该解决这个问题。

如果这不行，你应该尝试将你的DB_REAP_FREQ减少到5秒。