Question

我试图运行rake db:create或rake db:setup，但我收到以下错误消息。这很奇怪，因为rake db:create它与其他Rails项目的其他文件夹一起工作正常。

user:project user$ rake db:create
could not connect to server: No such file or directory
    Is the server running locally and accepting
    connections on Unix domain socket "/var/pgsql_socket/.s.PGSQL.5432"?
/Users/user/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-    3.1.0/lib/active_record/connection_adapters/postgresql_adapter.rb:991:in `initialize'
/Users/user/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-    3.1.0/lib/active_record/connection_adapters/postgresql_adapter.rb:991:in `new'
/Users/user/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-3.1.0/lib/active_record/connection_adapters/postgresql_adapter.rb:991:in `connect'
/Users/user/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-3.1.0/lib/active_record/connection_adapters/postgresql_adapter.rb:260:in `initialize'
/Users/user/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-3.1.0/lib/active_record/connection_adapters/postgresql_adapter.rb:27:in `new'
/Users/user/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-3.1.0/lib/active_record/connection_adapters/postgresql_adapter.rb:27:in `postgresql_connection'
/Users/user/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-    3.1.0/lib/active_record/connection_adapters/abstract/connection_pool.rb:304:in     `new_connection'
/Users/user/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-3.1.0/lib/active_record/connection_adapters/abstract/connection_pool.rb:323:in `checkout_new_connection'
/Users/user/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-    3.1.0/lib/active_record/connection_adapters/abstract/connection_pool.rb:265:in `block (2     levels) in checkout'
/Users/user/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-    3.1.0/lib/active_record/connection_adapters/abstract/connection_pool.rb:261:in `loop'
/Users/user/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-3.1.0/lib/active_record/connection_adapters/abstract/connection_pool.rb:261:in `block in checkout'
/Users/user/.rvm/rubies/ruby-1.9.2-p290/lib/ruby/1.9.1/monitor.rb:201:in `mon_synchronize'
/Users/user/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-3.1.0/lib/active_record/connection_adapters/abstract/connection_pool.rb:260:in `checkout'
/Users/user/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-3.1.0/lib/active_record/connection_adapters/abstract/connection_pool.rb:162:in `connection'
/Users/user/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-3.1.0/lib/active_record/connection_adapters/abstract/connection_pool.rb:409:in     `retrieve_connection'
/Users/user/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-3.1.0/lib/active_record/connection_adapters/abstract/connection_specification.rb:107:in `retrieve_connection'
/Users/user/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-3.1.0/lib/active_record/connection_adapters/abstract/connection_specification.rb:89:in `connection'
/Users/user/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-3.1.0/lib/active_record/railties/databases.rake:110:in `rescue in create_database'
/Users/user/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-3.1.0/lib/active_record/railties/databases.rake:54:in `create_database'
/Users/user/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-    3.1.0/lib/active_record/railties/databases.rake:42:in `block (2 levels) in <top (required)>'
/Users/user/.rvm/gems/ruby-1.9.2-p290/gems/rake-0.9.2.2/lib/rake/task.rb:205:in `call'
/Users/user/.rvm/gems/ruby-1.9.2-p290/gems/rake-0.9.2.2/lib/rake/task.rb:205:in `block in execute'
/Users/user/.rvm/gems/ruby-1.9.2-p290/gems/rake-0.9.2.2/lib/rake/task.rb:200:in `each'
/Users/user/.rvm/gems/ruby-1.9.2-p290/gems/rake-0.9.2.2/lib/rake/task.rb:200:in `execute'
/Users/user/.rvm/gems/ruby-1.9.2-p290/gems/rake-0.9.2.2/lib/rake/task.rb:158:in `block in invoke_with_call_chain'
/Users/user/.rvm/rubies/ruby-1.9.2-p290/lib/ruby/1.9.1/monitor.rb:201:in `mon_synchronize'
/Users/user/.rvm/gems/ruby-1.9.2-p290/gems/rake-0.9.2.2/lib/rake/task.rb:151:in `invoke_with_call_chain'
/Users/user/.rvm/gems/ruby-1.9.2-p290/gems/rake-0.9.2.2/lib/rake/task.rb:144:in `invoke'
/Users/user/.rvm/gems/ruby-1.9.2-p290/gems/rake-0.9.2.2/lib/rake/application.rb:116:in `invoke_task'
/Users/user/.rvm/gems/ruby-1.9.2-p290/gems/rake-0.9.2.2/lib/rake/application.rb:94:in `block (2 levels) in top_level'
/Users/user/.rvm/gems/ruby-1.9.2-p290/gems/rake-0.9.2.2/lib/rake/application.rb:94:in `each'
/Users/user/.rvm/gems/ruby-1.9.2-p290/gems/rake-0.9.2.2/lib/rake/application.rb:94:in `block in top_level'
/Users/user/.rvm/gems/ruby-1.9.2-p290/gems/rake-0.9.2.2/lib/rake/application.rb:133:in `standard_exception_handling'
/Users/user/.rvm/gems/ruby-1.9.2-p290/gems/rake-0.9.2.2/lib/rake/application.rb:88:in `top_level'
/Users/user/.rvm/gems/ruby-1.9.2-p290/gems/rake-0.9.2.2/lib/rake/application.rb:66:in `block in run'
/Users/user/.rvm/gems/ruby-1.9.2-p290/gems/rake-0.9.2.2/lib/rake/application.rb:133:in `standard_exception_handling'
/Users/user/.rvm/gems/ruby-1.9.2-p290/gems/rake-0.9.2.2/lib/rake/application.rb:63:in `run'
/Users/user/.rvm/gems/ruby-1.9.2-p290/gems/rake-0.9.2.2/bin/rake:33:in `<top (required)>'
/Users/user/.rvm/gems/ruby-1.9.2-p290/bin/rake:19:in `load'
/Users/user/.rvm/gems/ruby-1.9.2-p290/bin/rake:19:in `<main>'
Couldn't create database for {"adapter"=>"postgresql", "database"=>"project_test",     "username"=>nil, "password"=>nil, "min_messages"=>"warning"}

这是我的database.yml

development:
  adapter: postgresql
  database: project_development
  username:
  password:
  min_messages: warning

test:
  adapter: postgresql
  database: project_test
  username:
  password:
  min_messages: warning

production:
  adapter: postgresql
  database: project_production
  username:
  password:
  min_messages: warning

Posgree以/usr/local/var/postgres为单位。我不应该尝试在同一个文件夹中查找它而不是/var/pgsql_socket/吗？（无论如何我没有/ usr / local / var / pgsql_socket）

Answer 1

解决！

解决方案很简单，可以更新当前安装的宝石。

另一个尝试的解决方案是设置host: localhost或您在database.yml文件上的开发设置上使用的任何主机。

Answer 2

我通过Homebrew在Mac OS X上安装了PG（我没有意识到它在Mac OS X中是默认的），并且遇到了同样的问题。我可能通过在通过Homebrew安装pg之前安装pg gem来解决问题。

我通过执行以下操作解决了同样的问题：

确保所有二进制文件都指向Cellar目录中的二进制文件（Mac OS X上的/ usr / local / Cellar）
卸载pg gem gem uninstall pg
使用Homebrew configs gem install pg -- --with-pg-config=/usr/local/bin/pg_config重新安装（如果您使用pg setup创建了一个rails项目，这将在您的database.yml配置文件中进行说明）

它有效！

Answer 3

我遇到了同样的问题，并且能够通过以下方式解决错误：

使用postgresapp.com（由https://devcenter.heroku.com/articles/heroku-postgresql#local-setup中的heroku推荐），
添加到config / database.yml
```
host: localhost
```
按照http://postgresapp.com/documentation的问题排查部分中的建议重置共享内存设置：
```
sudo sysctl -w kern.sysv.shmall=65536
sudo sysctl -w kern.sysv.shmmax=16777216
```

Answer 4

上面zquintana的答案对我有一些小的警告。

我的解决方案（使用Homebrew）：

如果您安装了gem gem uninstall pg
删除postgresql brew uninstall postgresql
重新安装postgresql brew install postgresql
安装说明提到：

要在登录时启动postgresql：


ln -sfv /usr/local/opt/postgresql/*.plist ~/Library/LaunchAgents


然后立即加载postgresql：


launchctl load ~/Library/LaunchAgents/homebrew.mxcl.postgresql.plist


或者，如果您不想/需要launchctl，您可以运行：


postgres -D /usr/local/var/postgres

所以运行ln -sfv /usr/local/opt/postgresql/*.plist ~/Library/LaunchAgents
然后launchctl load ~/Library/LaunchAgents/homebrew.mxcl.postgresql.plist
现在使用Homebrew配置重新安装gem gem install pg -- --with-pg-config=/usr/local/bin/pg_config
现在运行您的rake db:create

Answer 5

就我而言，这就是我所需要的：https://dba.stackexchange.com/a/75221

var myObj = new { MyRootAttr = new { value = "My Value" } };
JavaScriptSerializer js = new JavaScriptSerializer();
string json = js.Serialize(myObj); //{"MyRootAttr":{"value":"My Value"}}

Answer 6

同时检查您是否没有打开的连接，例如客户端或连接到该实例的应用程序。如果发生这种情况，您将在错误

中看到这一点

Couldn't create database for {"adapter"=>"xxxx", "database"=>"xxxx", "host"=>"localhost", "username"=>"postgres", "password"=>"xxxxx", "pool"=>5, "timeout"=>5000}
rake aborted!
ActiveRecord::StatementInvalid: PG::ObjectInUse: ERROR:  source database "template1" is being accessed by other users
DETAIL:  There is 1 other session using the database.

Answer 7

首先，您需要在Postgres中手动创建用户，同时为此用户授予数据库创建权限（AKA createdb）。

首先，打开Postgres shell提示符

$ sudo -u postgres psql

创建您的用户

postgres=# create role Your_DB_username with createdb login password 'YOUR_PASSWORD';

退出Postgres shell

postgres=# \q

执行与db相关的任何rake任务：

$ rake db:create

它会起作用！

Answer 8

我能够通过确保database.yml文件中的数据库名称采用以下格式来解决这个问题：appname_development，appname_test和appname_production。这是我的database.yml文件作为示例：

    development:
      adapter: postgresql
      database: parallax_development
      username:
      password:

    test:
      adapter: postgresql
      database: parallax_test
      username:
      password:

    production:
      adapter: postgresql
      database: parallax_production
      username:
      password:

Answer 9

简单地将extend keyof T添加到您的数据库中。yml

有关更多详细信息，请访问rake db:create:all fails to connect to PostgreSQL database

在Rails中，无法为{＆＃34; adapter＆＃34; =＆gt;＆＃34; postgresql＆＃34;创建数据库，

9 个答案: