7

我现在在 Heroku 上使用共享的 postgres（开发/免费）计划，我在日志中看到了相当多的这个错误。不过，连接到 PG 数据库通常确实有效，所以我不确定这是否在我的控制范围内。Heroku 状态页面不会列出共享数据库发生这些情况时的任何停机时间。

使用 Rails 3.1.1 和Unicorn Web 服务器。

错误： 无法将主机名“pg60.sharedpg.heroku.com ( http://pg60.sharedpg.heroku.com )”转换为地址：名称或服务未知（PG::Error）

我的Unicorn配置文件（查看 Heroku 中 Unicorn 的推荐设置后）：

worker_processes 3 # amount of unicorn workers to spin up
timeout 30         # restarts workers that hang for 30 seconds
preload_app true

before_fork do |server, worker|
  # Replace with MongoDB or whatever
  if defined?(ActiveRecord::Base)
    ActiveRecord::Base.connection_handler.clear_all_connections!
    ActiveRecord::Base.connection.disconnect!
    Rails.logger.info('Disconnected from ActiveRecord')
  end

  # If you are using Redis but not Resque, change this
  if defined?(Resque)
    Resque.redis.quit
    Rails.logger.info('Disconnected from Redis')
  end
end

after_fork do |server, worker|
  # Replace with MongoDB or whatever
  if defined?(ActiveRecord::Base)
    ActiveRecord::Base.establish_connection
    ActiveRecord::Base.connection_handler.verify_active_connections!
    Rails.logger.info('Connected to ActiveRecord')
  end

  # If you are using Redis but not Resque, change this
  if defined?(Resque)
    Resque.redis = ENV['REDIS_URI']
    Rails.logger.info('Connected to Redis')
  end
end

痕迹：

 328 <13>1 2012-08-27T21:36:37+00:00 d.4122435c-cb44-421a-9a7d-a68bb10457d6 app web.1 (http://web.1) - - /app/vendor/bundle/ruby/1.9.1/gems/activerecord-3.1.1/lib/active_record/connection_adapters/postgresql_adapter.rb:1032:in `initialize': could not translate host name "pg60.sharedpg.heroku.com (http://pg60.sharedpg.heroku.com)" to address: Name or service not known (PG::Error)
219 <13>1 2012-08-27T21:36:37+00:00 d.4122435c-cb44-421a-9a7d-a68bb10457d6 app web.1 (http://web.1) - - from /app/vendor/bundle/ruby/1.9.1/gems/activerecord-3.1.1/lib/active_record/connection_adapters/postgresql_adapter.rb:1032:in `new'
223 <13>1 2012-08-27T21:36:37+00:00 d.4122435c-cb44-421a-9a7d-a68bb10457d6 app web.1 (http://web.1) - - from /app/vendor/bundle/ruby/1.9.1/gems/activerecord-3.1.1/lib/active_record/connection_adapters/postgresql_adapter.rb:1032:in `connect'
225 <13>1 2012-08-27T21:36:37+00:00 d.4122435c-cb44-421a-9a7d-a68bb10457d6 app web.1 (http://web.1) - - from /app/vendor/bundle/ruby/1.9.1/gems/activerecord-3.1.1/lib/active_record/connection_adapters/postgresql_adapter.rb:301:in `initialize'
217 <13>1 2012-08-27T21:36:37+00:00 d.4122435c-cb44-421a-9a7d-a68bb10457d6 app web.1 (http://web.1) - - from /app/vendor/bundle/ruby/1.9.1/gems/activerecord-3.1.1/lib/active_record/connection_adapters/postgresql_adapter.rb:28:in `new'
235 <13>1 2012-08-27T21:36:37+00:00 d.4122435c-cb44-421a-9a7d-a68bb10457d6 app web.1 (http://web.1) - - from /app/vendor/bundle/ruby/1.9.1/gems/activerecord-3.1.1/lib/active_record/connection_adapters/postgresql_adapter.rb:28:in `postgresql_connection'

328 <13>1 2012-08-27T21:36:37+00:00 d.4122435c-cb44-421a-9a7d-a68bb10457d6 app web.1 (http://web.1) - - /app/vendor/bundle/ruby/1.9.1/gems/activerecord-3.1.1/lib/active_record/connection_adapters/postgresql_adapter.rb:1032:in `initialize': could not translate host name "pg60.sharedpg.heroku.com (http://pg60.sharedpg.heroku.com)" to address: Name or service not known (PG::Error)
219 <13>1 2012-08-27T21:36:37+00:00 d.4122435c-cb44-421a-9a7d-a68bb10457d6 app web.1 (http://web.1) - - from /app/vendor/bundle/ruby/1.9.1/gems/activerecord-3.1.1/lib/active_record/connection_adapters/postgresql_adapter.rb:1032:in `new'
223 <13>1 2012-08-27T21:36:37+00:00 d.4122435c-cb44-421a-9a7d-a68bb10457d6 app web.1 (http://web.1) - - from /app/vendor/bundle/ruby/1.9.1/gems/activerecord-3.1.1/lib/active_record/connection_adapters/postgresql_adapter.rb:1032:in `connect'
225 <13>1 2012-08-27T21:36:37+00:00 d.4122435c-cb44-421a-9a7d-a68bb10457d6 app web.1 (http://web.1) - - from /app/vendor/bundle/ruby/1.9.1/gems/activerecord-3.1.1/lib/active_record/connection_adapters/postgresql_adapter.rb:301:in `initialize'
217 <13>1 2012-08-27T21:36:37+00:00 d.4122435c-cb44-421a-9a7d-a68bb10457d6 app web.1 (http://web.1) - - from /app/vendor/bundle/ruby/1.9.1/gems/activerecord-3.1.1/lib/active_record/connection_adapters/postgresql_adapter.rb:28:in `new'
235 <13>1 2012-08-27T21:36:37+00:00 d.4122435c-cb44-421a-9a7d-a68bb10457d6 app web.1 (http://web.1) - - from /app/vendor/bundle/ruby/1.9.1/gems/activerecord-3.1.1/lib/active_record/connection_adapters/postgresql_adapter.rb:28:in `postgresql_connection'
235 <13>1 2012-08-27T21:36:37+00:00 d.4122435c-cb44-421a-9a7d-a68bb10457d6 app web.1 (http://web.1) - - from /app/vendor/bundle/ruby/1.9.1/gems/activerecord-3.1.1/lib/active_record/connection_adapters/abstract/connection_pool.rb:304:in `new_connection'
244 <13>1 2012-08-27T21:36:37+00:00 d.4122435c-cb44-421a-9a7d-a68bb10457d6 app web.1 (http://web.1) - - from /app/vendor/bundle/ruby/1.9.1/gems/activerecord-3.1.1/lib/active_record/connection_adapters/abstract/connection_pool.rb:323:in `checkout_new_connection'
249 <13>1 2012-08-27T21:36:37+00:00 d.4122435c-cb44-421a-9a7d-a68bb10457d6 app web.1 (http://web.1) - - from /app/vendor/bundle/ruby/1.9.1/gems/activerecord-3.1.1/lib/active_record/connection_adapters/abstract/connection_pool.rb:265:in `block (2 levels) in checkout'
225 <13>1 2012-08-27T21:36:37+00:00 d.4122435c-cb44-421a-9a7d-a68bb10457d6 app web.1 (http://web.1) - - from /app/vendor/bundle/ruby/1.9.1/gems/activerecord-3.1.1/lib/active_record/connection_adapters/abstract/connection_pool.rb:261:in `loop'
238 <13>1 2012-08-27T21:36:37+00:00 d.4122435c-cb44-421a-9a7d-a68bb10457d6 app web.1 (http://web.1) - - from /app/vendor/bundle/ruby/1.9.1/gems/activerecord-3.1.1/lib/active_record/connection_adapters/abstract/connection_pool.rb:261:in `block in checkout'
153 <13>1 2012-08-27T21:36:37+00:00 d.4122435c-cb44-421a-9a7d-a68bb10457d6 app web.1 (http://web.1) - - from /usr/local/lib/ruby/1.9.1/monitor.rb:201:in `mon_synchronize'
229 <13>1 2012-08-27T21:36:37+00:00 d.4122435c-cb44-421a-9a7d-a68bb10457d6 app web.1 (http://web.1) - - from /app/vendor/bundle/ruby/1.9.1/gems/activerecord-3.1.1/lib/active_record/connection_adapters/abstract/connection_pool.rb:260:in `checkout'
231 <13>1 2012-08-27T21:36:37+00:00 d.4122435c-cb44-421a-9a7d-a68bb10457d6 app web.1 (http://web.1) - - from /app/vendor/bundle/ruby/1.9.1/gems/activerecord-3.1.1/lib/active_record/connection_adapters/abstract/connection_pool.rb:162:in `connection'
240 <13>1 2012-08-27T21:36:37+00:00 d.4122435c-cb44-421a-9a7d-a68bb10457d6 app web.1 (http://web.1) - - from /app/vendor/bundle/ruby/1.9.1/gems/activerecord-3.1.1/lib/active_record/connection_adapters/abstract/connection_pool.rb:409:in `retrieve_connection'
249 <13>1 2012-08-27T21:36:37+00:00 d.4122435c-cb44-421a-9a7d-a68bb10457d6 app web.1 (http://web.1) - - from /app/vendor/bundle/ruby/1.9.1/gems/activerecord-3.1.1/lib/active_record/connection_adapters/abstract/connection_specification.rb:107:in `retrieve_connection'
239 <13>1 2012-08-27T21:36:37+00:00 d.4122435c-cb44-421a-9a7d-a68bb10457d6 app web.1 (http://web.1) - - from /app/vendor/bundle/ruby/1.9.1/gems/activerecord-3.1.1/lib/active_record/connection_adapters/abstract/connection_specification.rb:89:in `connection'
194 <13>1 2012-08-27T21:36:37+00:00 d.4122435c-cb44-421a-9a7d-a68bb10457d6 app web.1 (http://web.1) - - from /app/vendor/bundle/ruby/1.9.1/gems/activerecord-3.1.1/lib/active_record/base.rb:703:in `table_exists?'
128 <13>1 2012-08-27T21:36:37+00:00 d.4122435c-cb44-421a-9a7d-a68bb10457d6 app web.1 (http://web.1) - - from /app/app.rb:38:in `<top (required)>'
116 <13>1 2012-08-27T21:36:37+00:00 d.4122435c-cb44-421a-9a7d-a68bb10457d6 app web.1 (http://web.1) - - from config.ru:9 (http://config.ru:9):in `require'
124 <13>1 2012-08-27T21:36:37+00:00 d.4122435c-cb44-421a-9a7d-a68bb10457d6 app web.1 (http://web.1) - - from config.ru:9 (http://config.ru:9):in `block in <main>'
179 <13>1 2012-08-27T21:36:37+00:00 d.4122435c-cb44-421a-9a7d-a68bb10457d6 app web.1 (http://web.1) - - from /app/vendor/bundle/ruby/1.9.1/gems/rack-1.4.1/lib/rack/builder.rb:51:in `instance_eval'
176 <13>1 2012-08-27T21:36:37+00:00 d.4122435c-cb44-421a-9a7d-a68bb10457d6 app web.1 (http://web.1) - - from /app/vendor/bundle/ruby/1.9.1/gems/rack-1.4.1/lib/rack/builder.rb:51:in `initialize'
112 <13>1 2012-08-27T21:36:37+00:00 d.4122435c-cb44-421a-9a7d-a68bb10457d6 app web.1 (http://web.1) - - from config.ru:1 (http://config.ru:1):in `new'
115 <13>1 2012-08-27T21:36:37+00:00 d.4122435c-cb44-421a-9a7d-a68bb10457d6 app web.1 (http://web.1) - - from config.ru:1 (http://config.ru:1):in `<main>'
168 <13>1 2012-08-27T21:36:37+00:00 d.4122435c-cb44-421a-9a7d-a68bb10457d6 app web.1 (http://web.1) - - from /app/vendor/bundle/ruby/1.9.1/gems/unicorn-4.2.0/lib/unicorn.rb:44:in `eval'
180 <13>1 2012-08-27T21:36:37+00:00 d.4122435c-cb44-421a-9a7d-a68bb10457d6 app web.1 (http://web.1) - - from /app/vendor/bundle/ruby/1.9.1/gems/unicorn-4.2.0/lib/unicorn.rb:44:in `block in builder'
181 <13>1 2012-08-27T21:36:37+00:00 d.4122435c-cb44-421a-9a7d-a68bb10457d6 app web.1 (http://web.1) - - from /app/vendor/bundle/ruby/1.9.1/gems/unicorn-4.2.0/lib/unicorn/http_server.rb:691:in `call'
187 <13>1 2012-08-27T21:36:37+00:00 d.4122435c-cb44-421a-9a7d-a68bb10457d6 app web.1 (http://web.1) - - from /app/vendor/bundle/ruby/1.9.1/gems/unicorn-4.2.0/lib/unicorn/http_server.rb:691:in `build_app!'
182 <13>1 2012-08-27T21:36:37+00:00 d.4122435c-cb44-421a-9a7d-a68bb10457d6 app web.1 (http://web.1) - - from /app/vendor/bundle/ruby/1.9.1/gems/unicorn-4.2.0/lib/unicorn/http_server.rb:136:in `start'
178 <13>1 2012-08-27T21:36:37+00:00 d.4122435c-cb44-421a-9a7d-a68bb10457d6 app web.1 (http://web.1) - - from /app/vendor/bundle/ruby/1.9.1/gems/unicorn-4.2.0/bin/unicorn:121:in `<top (required)>'
146 <13>1 2012-08-27T21:36:37+00:00 d.4122435c-cb44-421a-9a7d-a68bb10457d6 app web.1 (http://web.1) - - from /app/vendor/bundle/ruby/1.9.1/bin/unicorn:19:in `load'
148 <13>1 2012-08-27T21:36:37+00:00 d.4122435c-cb44-421a-9a7d-a68bb10457d6 app web.1 (http://web.1) - - from /app/vendor/bundle/ruby/1.9.1/bin/unicorn:19:in `<main>'
4

2 回答 2

7

那是一个DNS错误。极不可能与您的代码有任何关系。如果您的 Rails 应用程序和数据库都在 Heroku 中，请联系 Heroku 支持。

如果您的 Rails 应用程序在 Heroku 云之外运行（搜索“独角兽”一词表明它可能是这样的；请链接到这样的东西；不是每个人都知道“独角兽”是什么），您需要进行一些调试找出 DNS 问题出在哪里。它是您的应用程序使用的递归 DNS 服务器吗？一些更接近的缓存服务器？一些用于解析 Heroku 的 DNS 的中间服务器（不太可能）？Heroku的DNS本身？是否是丢包问题，服务器以误报响应的问题，循环集群中的一台坏服务器，......？预计会花费大量时间dig +trace与tracerouteor一起使用mtr- 假设您可以ssh进入。如果您有 root 权限，tcpdump并且tshark如果您可以访问它们，检查您正在使用的 DNS 服务器的日志也可能很有用。

如果您没有 shell 访问权限，那么您几乎必须得到与您托管的人的支持。

于 2012-08-28T23:24:16.533 回答
2

Just for reference, I had the same problem (Heroku was having an issue with AWS). Here was the helpful response from customer service (08/15):

We are occasionally seeing DNS resolution failure on our instances and we're working to solve this with AWS. The issue is really intermittent and unfortunately we're having hard time trying to identify the cause. While we're investigating, I have one workaround for this issue - currently, you're using Django's default way for the database connection - which is trying to make a new connection per request. This is pretty expensive, also this means you'll need to do DNS resolution for your every request which would increase the possibility to face this issue very unfortunately. Instead, I recommend that you use connection pooling. You can find some examples here:

https://devcenter.heroku.com/articles/python-concurrency-and-database-connections

One customer who was seeing this issue occasionally (but frequently, with Django app) saw a good improvement with the connection pooling, this should help a lot to prevent it from happening.

于 2015-08-24T22:46:16.693 回答