每次我运行 rails 4.0 服务器时，我都会得到这个输出。
Started GET "/" for 127.0.0.1 at 2013-11-06 23:56:36 -0500
PG::ConnectionBad - could not connect to server: Connection refused
Is the server running on host "localhost" (::1) and accepting
TCP/IP connections on port 5432?
could not connect to server: Connection refused
Is the server running on host "localhost" (127.0.0.1) and accepting
TCP/IP connections on port 5432?
could not connect to server: Connection refused
Is the server running on host "localhost" (fe80::1) and accepting
TCP/IP connections on port 5432?
:
activerecord (4.0.0) lib/active_record/connection_adapters/postgresql_adapter.rb:825:in `connect'
activerecord (4.0.0) lib/active_record/connection_adapters/postgresql_adapter.rb:542:in `initialize'
activerecord (4.0.0) lib/active_record/connection_adapters/postgresql_adapter.rb:41:in `postgresql_connection'
activerecord (4.0.0) lib/active_record/connection_adapters/abstract/connection_pool.rb:440:in `new_connection'
activerecord (4.0.0) lib/active_record/connection_adapters/abstract/connection_pool.rb:450:in `checkout_new_connection'
activerecord (4.0.0) lib/active_record/connection_adapters/abstract/connection_pool.rb:421:in `acquire_connection'
activerecord (4.0.0) lib/active_record/connection_adapters/abstract/connection_pool.rb:356:in `block in checkout'
/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/monitor.rb:211:in `mon_synchronize'
activerecord (4.0.0) lib/active_record/connection_adapters/abstract/connection_pool.rb:355:in `checkout'
activerecord (4.0.0) lib/active_record/connection_adapters/abstract/connection_pool.rb:265:in `block in connection'
/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/monitor.rb:211:in `mon_synchronize'
activerecord (4.0.0) lib/active_record/connection_adapters/abstract/connection_pool.rb:264:in `connection'
activerecord (4.0.0) lib/active_record/connection_adapters/abstract/connection_pool.rb:546:in `retrieve_connection'
activerecord (4.0.0) lib/active_record/connection_handling.rb:79:in `retrieve_connection'
activerecord (4.0.0) lib/active_record/connection_handling.rb:53:in `connection'
activerecord (4.0.0) lib/active_record/migration.rb:792:in `current_version'
activerecord (4.0.0) lib/active_record/migration.rb:800:in `needs_migration?'
activerecord (4.0.0) lib/active_record/migration.rb:379:in `check_pending!'
activerecord (4.0.0) lib/active_record/migration.rb:366:in `call'
actionpack (4.0.0) lib/action_dispatch/middleware/callbacks.rb:29:in `block in call'
activesupport (4.0.0) lib/active_support/callbacks.rb:373:in `_run__1613334440513032208__call__callbacks'
activesupport (4.0.0) lib/active_support/callbacks.rb:80:in `run_callbacks'
actionpack (4.0.0) lib/action_dispatch/middleware/callbacks.rb:27:in `call'
actionpack (4.0.0) lib/action_dispatch/middleware/reloader.rb:64:in `call'
actionpack (4.0.0) lib/action_dispatch/middleware/remote_ip.rb:76:in `call'
better_errors (0.9.0) lib/better_errors/middleware.rb:84:in `protected_app_call'
better_errors (0.9.0) lib/better_errors/middleware.rb:79:in `better_errors_call'
better_errors (0.9.0) lib/better_errors/middleware.rb:56:in `call'
actionpack (4.0.0) lib/action_dispatch/middleware/debug_exceptions.rb:17:in `call'
actionpack (4.0.0) lib/action_dispatch/middleware/show_exceptions.rb:30:in `call'
railties (4.0.0) lib/rails/rack/logger.rb:38:in `call_app'
railties (4.0.0) lib/rails/rack/logger.rb:21:in `block in call'
activesupport (4.0.0) lib/active_support/tagged_logging.rb:67:in `block in tagged'
activesupport (4.0.0) lib/active_support/tagged_logging.rb:25:in `tagged'
activesupport (4.0.0) lib/active_support/tagged_logging.rb:67:in `tagged'
railties (4.0.0) lib/rails/rack/logger.rb:21:in `call'
quiet_assets (1.0.2) lib/quiet_assets.rb:18:in `call_with_quiet_assets'
actionpack (4.0.0) lib/action_dispatch/middleware/request_id.rb:21:in `call'
rack (1.5.2) lib/rack/methodoverride.rb:21:in `call'
rack (1.5.2) lib/rack/runtime.rb:17:in `call'
activesupport (4.0.0) lib/active_support/cache/strategy/local_cache.rb:83:in `call'
rack (1.5.2) lib/rack/lock.rb:17:in `call'
actionpack (4.0.0) lib/action_dispatch/middleware/static.rb:64:in `call'
railties (4.0.0) lib/rails/engine.rb:511:in `call'
railties (4.0.0) lib/rails/application.rb:97:in `call'
rack (1.5.2) lib/rack/content_length.rb:14:in `call'
thin (1.5.1) lib/thin/connection.rb:81:in `block in pre_process'
thin (1.5.1) lib/thin/connection.rb:79:in `pre_process'
thin (1.5.1) lib/thin/connection.rb:54:in `process'
thin (1.5.1) lib/thin/connection.rb:39:in `receive_data'
eventmachine (1.0.3) lib/eventmachine.rb:187:in `run'
thin (1.5.1) lib/thin/backends/base.rb:63:in `start'
thin (1.5.1) lib/thin/server.rb:159:in `start'
rack (1.5.2) lib/rack/handler/thin.rb:16:in `run'
rack (1.5.2) lib/rack/server.rb:264:in `start'
railties (4.0.0) lib/rails/commands/server.rb:84:in `start'
railties (4.0.0) lib/rails/commands.rb:78:in `block in <top (required)>'
railties (4.0.0) lib/rails/commands.rb:73:in `<top (required)>'
bin/rails:4:in `<main>'
我运行的是 Mavericks OS X 10.9，所以我不知道这是否是问题所在。我已经尽我所能，但似乎没有任何效果。我已经多次卸载并安装了 postgres 和 pg gem。
这是我的database.yml文件
development:
adapter: postgresql
encoding: unicode
database: metals-directory_development
pool: 5
username:
password:
template: template0
host: localhost
port: 5432
test: &test
adapter: postgresql
encoding: unicode
database: metals-directory_test
pool: 5
username:
password:
template: template0
host: localhost
port: 5432
staging:
adapter: postgresql
encoding: unicode
database: metals-directory_production
pool: 5
username:
password:
template: template0
host: localhost
production:
adapter: postgresql
encoding: unicode
database: metals-directory_production
pool: 5
username:
password:
template: template0
host: localhost
cucumber:
<<: *test
最佳答案
它可以像陈旧的PID 文件 一样简单。它可能会静默失败，因为您的计算机没有完全完成关机过程，这意味着 postgres 没有删除 PID(进程 ID)文件。
postgres 使用 PID 文件来确保一次只有一个服务器实例在运行。所以当它再次启动时，它失败了，因为已经有一个 PID 文件告诉 postgres 服务器的另一个实例已启动(即使它没有运行，它只是没有关闭并删除 PID)。
- 要修复它，请删除/重命名 PID 文件。找到 postgres 数据目录。在使用自制软件的 macOS 上，它位于
/usr/local/var/postgres/中， 或者/usr/local/var/log/其他系统可能是/usr/var/postgres/。在 M1 上，它可能是/opt/homebrew/var/postgresql。 - 要确定这是问题所在，请查看日志文件 (
server.log)。在最后几行你会看到:
FATAL: lock file "postmaster.pid" already exists
HINT: Is another postmaster (PID 347) running in data directory "/usr/local/var/postgres"?
如果是，
rm postmaster.pid重新启动您的服务器。在使用 launchctl(使用自制软件)的 Mac 上，以下命令将重启服务器。
brew services restart postgresql
或者在旧版本的 Brew
launchctl unload homebrew.mxcl.postgresql.plist
launchctl load -w homebrew.mxcl.postgresql.plist
关于ruby-on-rails - PG::ConnectionBad - 无法连接到服务器:连接被拒绝，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/19828385/