昨天我已经安装了Postgres和pgAdminIII，都工作正常，但是重新加载后它停止工作。rails server后，我收到错误消息：
=> Booting Thin
=> Rails 3.2.13 application starting in development on http://0.0.0.0:3000
=> Call with -d to detach
=> Ctrl-C to shutdown server
Exiting
/home/home/.rvm/gems/ruby-1.9.3-p448/gems/activerecord-3.2.13/lib/active_record/connection_adapters/postgresql_adapter.rb:1216:in `initialize': could not connect to server: Connection refused (PG::ConnectionBad)
Is the server running on host "localhost" (127.0.0.1) and accepting
TCP/IP connections on port 5432?
from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/activerecord-3.2.13/lib/active_record/connection_adapters/postgresql_adapter.rb:1216:in `new'
from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/activerecord-3.2.13/lib/active_record/connection_adapters/postgresql_adapter.rb:1216:in `connect'
from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/activerecord-3.2.13/lib/active_record/connection_adapters/postgresql_adapter.rb:324:in `initialize'
from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/activerecord-3.2.13/lib/active_record/connection_adapters/postgresql_adapter.rb:28:in `new'
from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/activerecord-3.2.13/lib/active_record/connection_adapters/postgresql_adapter.rb:28:in `postgresql_connection'
from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/activerecord-3.2.13/lib/active_record/connection_adapters/abstract/connection_pool.rb:315:in `new_connection'
from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/activerecord-3.2.13/lib/active_record/connection_adapters/abstract/connection_pool.rb:325:in `checkout_new_connection'
from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/activerecord-3.2.13/lib/active_record/connection_adapters/abstract/connection_pool.rb:247:in `block (2 levels) in checkout'
from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/activerecord-3.2.13/lib/active_record/connection_adapters/abstract/connection_pool.rb:242:in `loop'
from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/activerecord-3.2.13/lib/active_record/connection_adapters/abstract/connection_pool.rb:242:in `block in checkout'
from /home/home/.rvm/rubies/ruby-1.9.3-p448/lib/ruby/1.9.1/monitor.rb:211:in `mon_synchronize'
from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/activerecord-3.2.13/lib/active_record/connection_adapters/abstract/connection_pool.rb:239:in `checkout'
from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/activerecord-3.2.13/lib/active_record/connection_adapters/abstract/connection_pool.rb:102:in `block in connection'
from /home/home/.rvm/rubies/ruby-1.9.3-p448/lib/ruby/1.9.1/monitor.rb:211:in `mon_synchronize'
from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/activerecord-3.2.13/lib/active_record/connection_adapters/abstract/connection_pool.rb:101:in `connection'
from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/activerecord-3.2.13/lib/active_record/connection_adapters/abstract/connection_pool.rb:410:in `retrieve_connection'
from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/activerecord-3.2.13/lib/active_record/connection_adapters/abstract/connection_specification.rb:171:in `retrieve_connection'
from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/activerecord-3.2.13/lib/active_record/connection_adapters/abstract/connection_specification.rb:145:in `connection'
from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/activerecord-3.2.13/lib/active_record/railtie.rb:88:in `block in <class:Railtie>'
from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/railties-3.2.13/lib/rails/initializable.rb:30:in `instance_exec'
from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/railties-3.2.13/lib/rails/initializable.rb:30:in `run'
from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/railties-3.2.13/lib/rails/initializable.rb:55:in `block in run_initializers'
from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/railties-3.2.13/lib/rails/initializable.rb:54:in `each'
from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/railties-3.2.13/lib/rails/initializable.rb:54:in `run_initializers'
from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/railties-3.2.13/lib/rails/application.rb:136:in `initialize!'
from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/railties-3.2.13/lib/rails/railtie/configurable.rb:30:in `method_missing'
from /home/home/Projects/mostdance/config/environment.rb:5:in `<top (required)>'
from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/activesupport-3.2.13/lib/active_support/dependencies.rb:251:in `require'
from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/activesupport-3.2.13/lib/active_support/dependencies.rb:251:in `block in require'
from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/activesupport-3.2.13/lib/active_support/dependencies.rb:236:in `load_dependency'
from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/activesupport-3.2.13/lib/active_support/dependencies.rb:251:in `require'
from /home/home/Projects/mostdance/config.ru:3:in `block in <main>'
from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/rack-1.4.5/lib/rack/builder.rb:51:in `instance_eval'
from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/rack-1.4.5/lib/rack/builder.rb:51:in `initialize'
from /home/home/Projects/mostdance/config.ru:in `new'
from /home/home/Projects/mostdance/config.ru:in `<main>'
from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/rack-1.4.5/lib/rack/builder.rb:40:in `eval'
from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/rack-1.4.5/lib/rack/builder.rb:40:in `parse_file'
from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/rack-1.4.5/lib/rack/server.rb:200:in `app'
from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/railties-3.2.13/lib/rails/commands/server.rb:46:in `app'
from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/rack-1.4.5/lib/rack/server.rb:304:in `wrapped_app'
from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/rack-1.4.5/lib/rack/server.rb:254:in `start'
from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/railties-3.2.13/lib/rails/commands/server.rb:70:in `start'
from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/railties-3.2.13/lib/rails/commands.rb:55:in `block in <top (required)>'
from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/railties-3.2.13/lib/rails/commands.rb:50:in `tap'
from /home/home/.rvm/gems/ruby-1.9.3-p448/gems/railties-3.2.13/lib/rails/commands.rb:50:in `<top (required)>'
from script/rails:6:in `require'
from script/rails:6:in `<main>'
这是我database.yml文件：
development:
host: localhost
adapter: postgresql
encoding: unicode
database: mydb
pool: 5
timeout: 5000
username: postgres
password: password
min_messages: WARNING
test:
host: localhost
adapter: sqlite3
database: db/test.sqlite3
pool: 5
timeout: 5000
production:
adapter: postgresql
encoding: unicode
database: mydb
pool: 5
timeout: 5000
username: postgres
password: password
host: 127.0.0.1
port: 5432
min_messages: WARNING
我也尝试运行服务器Postgres：
su postgres /etc/init.d/postgresql start
Password:
* Starting PostgreSQL 9.1 database server * Use of uninitialized value $info{"pgdata"} in -d at /usr/bin/pg_ctlcluster line 331.
Use of uninitialized value $info{"pgdata"} in concatenation (.) or string at /usr/bin/pg_ctlcluster line 332.
Error: is not accessible or does not exist
我也不知道为什么，但现在rails server放这个错误：
=> Booting Thin
=> Rails 3.2.13 application starting in development on http://0.0.0.0:3000
=> Call with -d to detach
=> Ctrl-C to shutdown server
Exiting
/home/home/.rvm/gems/ruby-1.9.3-p448/gems/activerecord-3.2.13/lib/active_record/connection_adapters/postgresql_adapter.rb:1216:in `initialize': FATAL: Peer authentication failed for user "postgres" (PG::ConnectionBad)
求你，帮帮我！如果您需要更多信息 - 写在评论中，我会更新我的问题
当我过去遇到这个问题时，我通常可以做一些事情来让它运行，其中大多数看起来很简单，但我非常健忘——
有时我在切换到 postgres 后实际上还没有创建数据库
bundle exec rake db:create
然后把我所有的桌子都放进去——
bundle exec rake db:migrate
其他时候我需要仔细检查并确保安装了 PG gem
gem install pg
如果您使用的是Mac，请尝试重新安装Postgresapp，然后重新启动所有内容。请确保再次导入数据库。
如果您使用的是 Linux，请重新安装 Postgres，然后重新启动所有内容。