mysql - Rails 应用程序无法连接到 mysql，无法通过套接字 '/var/run/mysqld/mysql.sock' (2) (Mysql2::Error) 连接到本地 MySQL 服务器

Question

我目前被困在 Rails 项目的(我希望是新人)问题上(这是我的第一个 Rails 项目，所以如果我错过任何重要的事情，我深表歉意)。我已经在这里待了几个小时，似乎找不到任何解决方案。我已经尝试了以下线程的解决方案，但无济于事。

connect to local MySQL server through socket

Can't connect to local MySQL server through socket

Can't connect to local MySQL server through socket '/tmp/mysql.sock' (2)

Can't connect to local MySQL server through socket '/tmp/mysql.sock'

list 还在继续，无论如何，有些线程与我的情况相似，其他线程只是捕获救命稻草。让我快速概述一下我的情况。

• 项目是在mac上开发的
  • 我最近设置了一个测试服务器作为学习部署过程的一种方式
  • 服务器正在运行 Ubuntu Server 12.04

我设法按照一些教程进行设置，包括 Capistrano部署教程到:

$ rake RAILS_ENV=production db:schema:load

这是我第一次遇到无法连接到本地 MySQL 服务器错误的地方。

如果我使用 --trace 运行它，我会得到以下输出:

** Invoke db:schema:load (first_time)
** Invoke environment (first_time)
** Execute environment
rake aborted!
Can't connect to local MySQL server through socket '/var/run/mysqld/mysql.sock' (2)
/usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/gems/mysql2-0.3.11/lib/mysql2/client.rb:44:in `connect'
/usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/gems/mysql2-0.3.11/lib/mysql2/client.rb:44:in `initialize'
/usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/gems/activerecord-3.2.2/lib/active_record/connection_adapters/mysql2_adapter.rb:16:in `new'
/usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/gems/activerecord-3.2.2/lib/active_record/connection_adapters/mysql2_adapter.rb:16:in `mysql2_connection'
/usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/gems/activerecord-3.2.2/lib/active_record/connection_adapters/abstract/connection_pool.rb:277:in `new_connection'
/usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/gems/activerecord-3.2.2/lib/active_record/connection_adapters/abstract/connection_pool.rb:287:in `checkout_new_connection'
/usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/gems/activerecord-3.2.2/lib/active_record/connection_adapters/abstract/connection_pool.rb:235:in `block (2 levels) in checkout'
/usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/gems/activerecord-3.2.2/lib/active_record/connection_adapters/abstract/connection_pool.rb:230:in `loop'
/usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/gems/activerecord-3.2.2/lib/active_record/connection_adapters/abstract/connection_pool.rb:230:in `block in checkout'
/usr/share/ruby-rvm/rubies/ruby-1.9.2-p318/lib/ruby/1.9.1/monitor.rb:201:in `mon_synchronize'
/usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/gems/activerecord-3.2.2/lib/active_record/connection_adapters/abstract/connection_pool.rb:229:in `checkout'
/usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/gems/activerecord-3.2.2/lib/active_record/connection_adapters/abstract/connection_pool.rb:95:in `connection'
/usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/gems/activerecord-3.2.2/lib/active_record/connection_adapters/abstract/connection_pool.rb:374:in `retrieve_connection'
/usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/gems/activerecord-3.2.2/lib/active_record/connection_adapters/abstract/connection_specification.rb:168:in `retrieve_connection'
/usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/gems/activerecord-3.2.2/lib/active_record/connection_adapters/abstract/connection_specification.rb:142:in `connection'
/usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/gems/activerecord-3.2.2/lib/active_record/model_schema.rb:308:in `clear_cache!'
/usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/gems/activerecord-3.2.2/lib/active_record/railtie.rb:91:in `block (2 levels) in <class:Railtie>'
/usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/gems/activesupport-3.2.2/lib/active_support/callbacks.rb:418:in `_run__427268845__prepare__407057367__callbacks'
/usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/gems/activesupport-3.2.2/lib/active_support/callbacks.rb:405:in `__run_callback'
/usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/gems/activesupport-3.2.2/lib/active_support/callbacks.rb:385:in `_run_prepare_callbacks'
/usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/gems/activesupport-3.2.2/lib/active_support/callbacks.rb:81:in `run_callbacks'
/usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/gems/actionpack-3.2.2/lib/action_dispatch/middleware/reloader.rb:74:in `prepare!'
/usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/gems/actionpack-3.2.2/lib/action_dispatch/middleware/reloader.rb:48:in `prepare!'
/usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/gems/railties-3.2.2/lib/rails/application/finisher.rb:47:in `block in <module:Finisher>'
/usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/gems/railties-3.2.2/lib/rails/initializable.rb:30:in `instance_exec'
/usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/gems/railties-3.2.2/lib/rails/initializable.rb:30:in `run'
/usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/gems/railties-3.2.2/lib/rails/initializable.rb:55:in `block in run_initializers'
/usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/gems/railties-3.2.2/lib/rails/initializable.rb:54:in `each'
/usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/gems/railties-3.2.2/lib/rails/initializable.rb:54:in `run_initializers'
/usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/gems/railties-3.2.2/lib/rails/application.rb:136:in `initialize!'
/usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/gems/railties-3.2.2/lib/rails/railtie/configurable.rb:30:in `method_missing'
/var/www/little_oven_deploy/releases/20120705162026/config/environment.rb:5:in `<top (required)>'
/usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/gems/activesupport-3.2.2/lib/active_support/dependencies.rb:251:in `require'
/usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/gems/activesupport-3.2.2/lib/active_support/dependencies.rb:251:in `block in require'
/usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/gems/activesupport-3.2.2/lib/active_support/dependencies.rb:236:in `load_dependency'
/usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/gems/activesupport-3.2.2/lib/active_support/dependencies.rb:251:in `require'
/usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/gems/railties-3.2.2/lib/rails/application.rb:103:in `require_environment!'
/usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/gems/railties-3.2.2/lib/rails/application.rb:292:in `block (2 levels) in initialize_tasks'
/usr/share/ruby-rvm/gems/ruby-1.9.2-p318@global/gems/rake-0.9.2.2/lib/rake/task.rb:205:in `call'
/usr/share/ruby-rvm/gems/ruby-1.9.2-p318@global/gems/rake-0.9.2.2/lib/rake/task.rb:205:in `block in execute'
/usr/share/ruby-rvm/gems/ruby-1.9.2-p318@global/gems/rake-0.9.2.2/lib/rake/task.rb:200:in `each'
/usr/share/ruby-rvm/gems/ruby-1.9.2-p318@global/gems/rake-0.9.2.2/lib/rake/task.rb:200:in `execute'
/usr/share/ruby-rvm/gems/ruby-1.9.2-p318@global/gems/rake-0.9.2.2/lib/rake/task.rb:158:in `block in invoke_with_call_chain'
/usr/share/ruby-rvm/rubies/ruby-1.9.2-p318/lib/ruby/1.9.1/monitor.rb:201:in `mon_synchronize'
/usr/share/ruby-rvm/gems/ruby-1.9.2-p318@global/gems/rake-0.9.2.2/lib/rake/task.rb:151:in `invoke_with_call_chain'
/usr/share/ruby-rvm/gems/ruby-1.9.2-p318@global/gems/rake-0.9.2.2/lib/rake/task.rb:176:in `block in invoke_prerequisites'
/usr/share/ruby-rvm/gems/ruby-1.9.2-p318@global/gems/rake-0.9.2.2/lib/rake/task.rb:174:in `each'
/usr/share/ruby-rvm/gems/ruby-1.9.2-p318@global/gems/rake-0.9.2.2/lib/rake/task.rb:174:in `invoke_prerequisites'
/usr/share/ruby-rvm/gems/ruby-1.9.2-p318@global/gems/rake-0.9.2.2/lib/rake/task.rb:157:in `block in invoke_with_call_chain'
/usr/share/ruby-rvm/rubies/ruby-1.9.2-p318/lib/ruby/1.9.1/monitor.rb:201:in `mon_synchronize'
/usr/share/ruby-rvm/gems/ruby-1.9.2-p318@global/gems/rake-0.9.2.2/lib/rake/task.rb:151:in `invoke_with_call_chain'
/usr/share/ruby-rvm/gems/ruby-1.9.2-p318@global/gems/rake-0.9.2.2/lib/rake/task.rb:144:in `invoke'
/usr/share/ruby-rvm/gems/ruby-1.9.2-p318@global/gems/rake-0.9.2.2/lib/rake/application.rb:116:in `invoke_task'
/usr/share/ruby-rvm/gems/ruby-1.9.2-p318@global/gems/rake-0.9.2.2/lib/rake/application.rb:94:in `block (2 levels) in top_level'
/usr/share/ruby-rvm/gems/ruby-1.9.2-p318@global/gems/rake-0.9.2.2/lib/rake/application.rb:94:in `each'
/usr/share/ruby-rvm/gems/ruby-1.9.2-p318@global/gems/rake-0.9.2.2/lib/rake/application.rb:94:in `block in top_level'
/usr/share/ruby-rvm/gems/ruby-1.9.2-p318@global/gems/rake-0.9.2.2/lib/rake/application.rb:133:in `standard_exception_handling'
/usr/share/ruby-rvm/gems/ruby-1.9.2-p318@global/gems/rake-0.9.2.2/lib/rake/application.rb:88:in `top_level'
/usr/share/ruby-rvm/gems/ruby-1.9.2-p318@global/gems/rake-0.9.2.2/lib/rake/application.rb:66:in `block in run'
/usr/share/ruby-rvm/gems/ruby-1.9.2-p318@global/gems/rake-0.9.2.2/lib/rake/application.rb:133:in `standard_exception_handling'
/usr/share/ruby-rvm/gems/ruby-1.9.2-p318@global/gems/rake-0.9.2.2/lib/rake/application.rb:63:in `run'
/usr/share/ruby-rvm/gems/ruby-1.9.2-p318@global/gems/rake-0.9.2.2/bin/rake:33:in `<top (required)>'
/usr/share/ruby-rvm/gems/ruby-1.9.2-p318@global/bin/rake:19:in `load'
/usr/share/ruby-rvm/gems/ruby-1.9.2-p318@global/bin/rake:19:in `<main>'
/usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/bin/ruby_noexec_wrapper:14:in `eval'
/usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/bin/ruby_noexec_wrapper:14:in `<main>'
Tasks: TOP => db:schema:load => environment

我的database.yml文件如下:

# MySQL.  Versions 4.1 and 5.0 are recommended.
#
# Install the MYSQL driver
#   gem install mysql2
#
# Ensure the MySQL gem is defined in your Gemfile
#   gem 'mysql2'
#
# And be sure to use new-style password hashing:
#   http://dev.mysql.com/doc/refman/5.0/en/old-client.html
development:
  adapter: mysql2
  encoding: utf8
  reconnect: false
  database: little_oven_devel
  pool: 5
  username: devel
  password: Development1
  socket: /var/run/mysqld/mysql.sock

# Warning: The database defined as "test" will be erased and
# re-generated from your development database when you run "rake".
# Do not set this db to the same as development or production.
test:
  adapter: mysql2
  encoding: utf8
  reconnect: false
  database: little_oven_test
  pool: 5
  username: root
  password:
  socket: /tmp/mysql.sock

production:
  adapter: mysql2
  encoding: utf8
  reconnect: false
  database: little_oven_production
  pool: 5
  username: production
  password: Production1
  socket: /var/run/mysqld/mysql.sock

请注意，我已经更改了 socket 变量的位置以与我认为是 ubuntu 上的 .sock 文件相对应，因为这与 mac OSX 上的标准安装不同。

最后，我在运行的时候也报同样的错误

rails c

输出如下:

/usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/gems/mysql2-0.3.11/lib/mysql2/client.rb:44:in `connect': Can't connect to local MySQL server through socket '/var/run/mysqld/mysql.sock' (2) (Mysql2::Error)
    from /usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/gems/mysql2-0.3.11/lib/mysql2/client.rb:44:in `initialize'
    from /usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/gems/activerecord-3.2.2/lib/active_record/connection_adapters/mysql2_adapter.rb:16:in `new'
    from /usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/gems/activerecord-3.2.2/lib/active_record/connection_adapters/mysql2_adapter.rb:16:in `mysql2_connection'
    from /usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/gems/activerecord-3.2.2/lib/active_record/connection_adapters/abstract/connection_pool.rb:277:in `new_connection'
    from /usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/gems/activerecord-3.2.2/lib/active_record/connection_adapters/abstract/connection_pool.rb:287:in `checkout_new_connection'
    from /usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/gems/activerecord-3.2.2/lib/active_record/connection_adapters/abstract/connection_pool.rb:235:in `block (2 levels) in checkout'
    from /usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/gems/activerecord-3.2.2/lib/active_record/connection_adapters/abstract/connection_pool.rb:230:in `loop'
    from /usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/gems/activerecord-3.2.2/lib/active_record/connection_adapters/abstract/connection_pool.rb:230:in `block in checkout'
    from /usr/share/ruby-rvm/rubies/ruby-1.9.2-p318/lib/ruby/1.9.1/monitor.rb:201:in `mon_synchronize'
    from /usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/gems/activerecord-3.2.2/lib/active_record/connection_adapters/abstract/connection_pool.rb:229:in `checkout'
    from /usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/gems/activerecord-3.2.2/lib/active_record/connection_adapters/abstract/connection_pool.rb:95:in `connection'
    from /usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/gems/activerecord-3.2.2/lib/active_record/connection_adapters/abstract/connection_pool.rb:374:in `retrieve_connection'
    from /usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/gems/activerecord-3.2.2/lib/active_record/connection_adapters/abstract/connection_specification.rb:168:in `retrieve_connection'
    from /usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/gems/activerecord-3.2.2/lib/active_record/connection_adapters/abstract/connection_specification.rb:142:in `connection'
    from /usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/gems/activerecord-3.2.2/lib/active_record/model_schema.rb:308:in `clear_cache!'
    from /usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/gems/activerecord-3.2.2/lib/active_record/railtie.rb:91:in `block (2 levels) in <class:Railtie>'
    from /usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/gems/activesupport-3.2.2/lib/active_support/callbacks.rb:418:in `_run__485859349__prepare__1069885904__callbacks'
    from /usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/gems/activesupport-3.2.2/lib/active_support/callbacks.rb:405:in `__run_callback'
    from /usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/gems/activesupport-3.2.2/lib/active_support/callbacks.rb:385:in `_run_prepare_callbacks'
    from /usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/gems/activesupport-3.2.2/lib/active_support/callbacks.rb:81:in `run_callbacks'
    from /usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/gems/actionpack-3.2.2/lib/action_dispatch/middleware/reloader.rb:74:in `prepare!'
    from /usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/gems/actionpack-3.2.2/lib/action_dispatch/middleware/reloader.rb:48:in `prepare!'
    from /usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/gems/railties-3.2.2/lib/rails/application/finisher.rb:47:in `block in <module:Finisher>'
    from /usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/gems/railties-3.2.2/lib/rails/initializable.rb:30:in `instance_exec'
    from /usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/gems/railties-3.2.2/lib/rails/initializable.rb:30:in `run'
    from /usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/gems/railties-3.2.2/lib/rails/initializable.rb:55:in `block in run_initializers'
    from /usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/gems/railties-3.2.2/lib/rails/initializable.rb:54:in `each'
    from /usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/gems/railties-3.2.2/lib/rails/initializable.rb:54:in `run_initializers'
    from /usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/gems/railties-3.2.2/lib/rails/application.rb:136:in `initialize!'
    from /usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/gems/railties-3.2.2/lib/rails/railtie/configurable.rb:30:in `method_missing'
    from /var/www/little_oven_deploy/releases/20120705162026/config/environment.rb:5:in `<top (required)>'
    from /usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/gems/activesupport-3.2.2/lib/active_support/dependencies.rb:251:in `require'
    from /usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/gems/activesupport-3.2.2/lib/active_support/dependencies.rb:251:in `block in require'
    from /usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/gems/activesupport-3.2.2/lib/active_support/dependencies.rb:236:in `load_dependency'
    from /usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/gems/activesupport-3.2.2/lib/active_support/dependencies.rb:251:in `require'
    from /usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/gems/railties-3.2.2/lib/rails/application.rb:103:in `require_environment!'
    from /usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/gems/railties-3.2.2/lib/rails/commands.rb:40:in `<top (required)>'
    from script/rails:6:in `require'
    from script/rails:6:in `<main>'

我想指出位置/usr/share/ruby-rvm/gems/ruby-1.9.2-p318@rails_3_2/gems/mysql2-0.3.11/lib/mysql2/client.rb 是有效的.此外，mysql 正在运行，我可以通过以下方式访问它:

mysql -u production -p

Answer 1

您也可以在 database.yml 中从生产环境中删除套接字规范

production:
  # socket: /var/run/mysqld/mysql.sock

我知道性能略有下降，但它帮助我解决了类似的问题。