ResqueはMysql2 ::エラーを返している：

Question

Resque users` Mysql2 ::エラーを返して `でSHOW FIELDS：：MySQLの接続を閉じusersマイワーカークラスがどのように見える

Worker 
    8608f362-819b-4c15-b42b-69c4df00d27b:1 on low at about 16 hours ago 
Class 
    AddLiveView 
Arguments 

    4383 
    {"remote_ip"=>"184.72.47.71", "expires"=>true} 

Exception 
    ActiveRecord::StatementInvalid 
Error 
    Mysql2::Error: closed MySQL connection: SHOW FIELDS FROM `users` 

    /app/vendor/bundle/ruby/1.9.1/gems/activerecord-3.1.3/lib/active_record/connection_adapters/mysql2_adapter.rb:283:in `query' 
    /app/vendor/bundle/ruby/1.9.1/gems/activerecord-3.1.3/lib/active_record/connection_adapters/mysql2_adapter.rb:283:in `block in execute' 
    /app/vendor/bundle/ruby/1.9.1/gems/activerecord-3.1.3/lib/active_record/connection_adapters/abstract_adapter.rb:244:in `block in log' 
    /app/vendor/bundle/ruby/1.9.1/gems/activesupport-3.1.3/lib/active_support/notifications/instrumenter.rb:21:in `instrument' 
    /app/vendor/bundle/ruby/1.9.1/gems/activerecord-3.1.3/lib/active_record/connection_adapters/abstract_adapter.rb:239:in `log' 
    /app/vendor/bundle/ruby/1.9.1/gems/activerecord-3.1.3/lib/active_record/connection_adapters/mysql2_adapter.rb:283:in `execute' 
    /app/vendor/bundle/ruby/1.9.1/gems/activerecord-3.1.3/lib/active_record/connection_adapters/mysql2_adapter.rb:473:in `columns' 
    /app/vendor/bundle/ruby/1.9.1/gems/activerecord-3.1.3/lib/active_record/connection_adapters/abstract/connection_pool.rb:95:in `block (2 levels) in initialize' 
    /app/vendor/bundle/ruby/1.9.1/gems/activerecord-3.1.3/lib/active_record/connection_adapters/abstract/connection_pool.rb:185:in `with_connection' 
    /app/vendor/bundle/ruby/1.9.1/gems/activerecord-3.1.3/lib/active_record/connection_adapters/abstract/connection_pool.rb:92:in `block in initialize' 
    /app/vendor/bundle/ruby/1.9.1/gems/activerecord-3.1.3/lib/active_record/connection_adapters/abstract/connection_pool.rb:106:in `yield' 
    /app/vendor/bundle/ruby/1.9.1/gems/activerecord-3.1.3/lib/active_record/connection_adapters/abstract/connection_pool.rb:106:in `default' 
    /app/vendor/bundle/ruby/1.9.1/gems/activerecord-3.1.3/lib/active_record/connection_adapters/abstract/connection_pool.rb:106:in `block in initialize' 
    /app/vendor/bundle/ruby/1.9.1/gems/activerecord-3.1.3/lib/active_record/base.rb:717:in `yield' 
    /app/vendor/bundle/ruby/1.9.1/gems/activerecord-3.1.3/lib/active_record/base.rb:717:in `default' 
    /app/vendor/bundle/ruby/1.9.1/gems/activerecord-3.1.3/lib/active_record/base.rb:717:in `columns_hash' 
    /app/vendor/bundle/ruby/1.9.1/gems/activerecord-3.1.3/lib/active_record/locking/optimistic.rb:145:in `locking_enabled?' 
    /app/vendor/bundle/ruby/1.9.1/gems/activerecord-3.1.3/lib/active_record/relation.rb:110:in `to_a' 
    /app/vendor/bundle/ruby/1.9.1/gems/activerecord-3.1.3/lib/active_record/relation/finder_methods.rb:376:in `find_first' 
    /app/vendor/bundle/ruby/1.9.1/gems/activerecord-3.1.3/lib/active_record/relation/finder_methods.rb:122:in `first' 
    /app/vendor/bundle/ruby/1.9.1/gems/activerecord-3.1.3/lib/active_record/associations/singular_association.rb:42:in `find_target' 
    /app/vendor/bundle/ruby/1.9.1/gems/activerecord-3.1.3/lib/active_record/associations/association.rb:146:in `load_target' 
    /app/vendor/bundle/ruby/1.9.1/gems/activerecord-3.1.3/lib/active_record/associations/association.rb:56:in `reload' 
    /app/vendor/bundle/ruby/1.9.1/gems/activerecord-3.1.3/lib/active_record/associations/singular_association.rb:9:in `reader' 
    /app/vendor/bundle/ruby/1.9.1/gems/activerecord-3.1.3/lib/active_record/associations/builder/association.rb:41:in `block in define_readers' 
    /app/app/workers/add_live_view.rb:24:in `block in perform' 
    /usr/local/lib/ruby/1.9.1/timeout.rb:58:in `timeout' 
    /app/app/workers/add_live_view.rb:13:in `perform' 

でSHOW FIELDS：MySQLの接続を閉じました。コンソールで

class AddLiveView 
    @queue = :low 

    def self.perform(song_id, options) 
    begin 
     song = Song.find(song_id) 
     current_user = User.find(options['current_user_id']) if !options['expires'] 
    rescue 
     puts "Error #{$!}" 
    end 

    begin 
     Timeout.timeout(30.seconds) do 
     if options['expires'] 
      # live_view = LiveView.add_live_view_that_expires(song, options['remote_ip']) 
      ip_to_country = IpToCountry.where('ip_to_countries.ip_number_to >= INET_ATON(?)', options['remote_ip']).order('ip_number_to ASC').limit(1).first 

      live_view = LiveView.new(:live_viewable => song, :live_viewable_category => 'View', :expires => true, :expires_at => 1.month.from_now, :ip => options['remote_ip'], :country_name => ip_to_country.country_name, :iso_two_letter_country_code => ip_to_country.iso_two_letter_country_code) 

      if live_view.save 
      Pusher["#{song.class.to_s.underscore}_#{song.id}"].trigger('live_view', { 
       :user   => nil, 
       :live_viewable => live_view.live_viewable, 
       :artist  => live_view.live_viewable.user 
      }) 

      # We do this in the worker, because we want the live_view object to exist when we push it to our notification service 
      # Only keep data from last 30 days 
      LiveView.where('live_views.expires = ? AND live_views.expires_at < ?', true, Date.today).destroy_all 
      end 
     else 
      # ... do something else here ... 
     end 
     end 
    rescue Timeout::Error 
    end 
    end 
end 

、私がやって手動でそれをやってみました：

song = Song.find(4383) 
ip_to_country = IpToCountry.where('ip_to_countries.ip_number_to >= INET_ATON(?)', '184.72.47.71').order('ip_number_to ASC').limit(1).first 
live_view = LiveView.new(:live_viewable => song, :live_viewable_category => 'View', :expires => true, :expires_at => 1.month.from_now, :ip => '184.72.47.71', :country_name => ip_to_country.country_name, :iso_two_letter_country_code => ip_to_country.iso_two_letter_country_code) 
live_view.save 
live_view.live_viewable.user 

すべてのw orks！本番環境でエラーが表示されるのはなぜですか？これは、同時に多くの接続がdbに当たってタイムアウト制限に達していることでしょうか？

Answer 1

Could this be that there are many connections hitting the db at the same time and the timeout limit is being reached?

そうかもしれません。 Railsのコンソールで簡単にそのようなことを示すことができます。

$ rails console 
Loading development environment (Rails 3.2.2) 
1.9.3-p125 :001 > require 'timeout' 
=> true 
1.9.3-p125 :002 > Timeout.timeout(1) { User.find_by_sql('SELECT sleep(2) FROM users;') } 
    User Load (974.4ms) SELECT sleep(2) FROM users; 
: execution expired: SELECT sleep(2) FROM users; 
ActiveRecord::StatementInvalid: : execution expired: SELECT sleep(2) FROM users; 
     from /Users/sluukkonen/.rvm/gems/ruby-1.9.3-p125/gems/activerecord-3.2.2/lib/active_record/connection_adapters/abstract_mysql_adapter.rb:243:in `query' 
# Skip the rest of the backtrace... 

この後、データベースへのすべてのクエリは、接続が閉じられると、Mysql2 :: Errorを発生させます。

1.9.3-p125 :003 > User.count 
Mysql2::Error: closed MySQL connection: SHOW FULL FIELDS FROM `users` 
ActiveRecord::StatementInvalid: Mysql2::Error: closed MySQL connection: SHOW FULL FIELDS FROM `users` 
    from /Users/sluukkonen/.rvm/gems/ruby-1.9.3-p125/gems/activerecord-3.2.2/lib/active_record/connection_adapters/abstract_mysql_adapter.rb:243:in `query' 
# Again, skip the rest of the backtrace.. 

は私が意図した動作が何であるかわからないんだけど、そうMysql2またはActiveRecordの中にバグがある場合、私は言うことはできませんが、PGの宝石ではPostgreSQLを使用すると、類似の挙動（後続の問合せを示しません正常に実行される）。

reconnect: trueをdatabase.ymlに追加すると問題が解決するはずですが、追加することになることに注意してください。caveats