連接被拒絕（PGError）（postgresql 和 rails）

Question

當我嘗試使用“$rails s”運行我的本地主機時，我不斷收到此錯誤：

(Mac OSX 10.8.3) (ruby 2.0.0p195 (2013-05-14 revision 40734) [x86_64-darwin12.3.0]) (Rails 3.2.11) (psql (PostgreSQL) 9.2.2 ) **與自制軟件一起安裝

我一直在卸載 postgresql 並重新安裝，所以我預感到某處可能存在沖突的庫……我只是不知道從哪里開始。

我將 Postgresql 9.1 和 9.2 放在同一個文件夾中，然后將 9.1 移到了垃圾箱中。

這是我在終端中運行“rails s”時的輸出

Danny$ rails s
^[b=> Booting Thin
=> Rails 3.2.11 application starting in development on http://0.0.0.0:3000
=> Call with -d to detach
=> Ctrl-C to shutdown server
Exiting
/Users/Danny/.rvm/gems/ruby-2.0.0-p195/gems/activerecord-3.2.11/lib/active_record/connection_adapters/postgresql_adapter.rb:1208:in `initialize': could        not connect to server: Connection refused (PGError)
Is the server running on host "localhost" (127.0.0.1) and accepting
TCP/IP connections on port 5433?
could not connect to server: Connection refused
Is the server running on host "localhost" (::1) and accepting
TCP/IP connections on port 5433?
could not connect to server: Connection refused
Is the server running on host "localhost" (fe80::1) and accepting
TCP/IP connections on port 5433?
from /Users/Danny/.rvm/gems/ruby-2.0.0-p195/gems/activerecord-3.2.11/lib/active_record/connection_adapters/postgresql_adapter.rb:1208:in `new'
from /Users/Danny/.rvm/gems/ruby-2.0.0-p195/gems/activerecord-3.2.11/lib/active_record/connection_adapters/postgresql_adapter.rb:1208:in `connect'
from /Users/Danny/.rvm/gems/ruby-2.0.0-p195/gems/activerecord-3.2.11/lib/active_record/connection_adapters/postgresql_adapter.rb:326:in `initialize'
from /Users/Danny/.rvm/gems/ruby-2.0.0-p195/gems/activerecord-3.2.11/lib/active_record/connection_adapters/postgresql_adapter.rb:28:in `new'
from /Users/Danny/.rvm/gems/ruby-2.0.0-p195/gems/activerecord-3.2.11/lib/active_record/connection_adapters/postgresql_adapter.rb:28:in `postgresql_connection'
from /Users/Danny/.rvm/gems/ruby-2.0.0-p195/gems/activerecord-3.2.11/lib/active_record/connection_adapters/abstract/connection_pool.rb:315:in `new_connection'
from /Users/Danny/.rvm/gems/ruby-2.0.0-p195/gems/activerecord-3.2.11/lib/active_record/connection_adapters/abstract/connection_pool.rb:325:in `checkout_new_connection'
from /Users/Danny/.rvm/gems/ruby-2.0.0-p195/gems/activerecord-3.2.11/lib/active_record/connection_adapters/abstract/connection_pool.rb:247:in `block (2 levels) in checkout'
from /Users/Danny/.rvm/gems/ruby-2.0.0-p195/gems/activerecord-3.2.11/lib/active_record/connection_adapters/abstract/connection_pool.rb:242:in `loop'
from /Users/Danny/.rvm/gems/ruby-2.0.0-p195/gems/activerecord-3.2.11/lib/active_record/connection_adapters/abstract/connection_pool.rb:242:in `block in checkout'
from /Users/Danny/.rvm/rubies/ruby-2.0.0-p195/lib/ruby/2.0.0/monitor.rb:211:in `mon_synchronize'
from /Users/Danny/.rvm/gems/ruby-2.0.0-p195/gems/activerecord-3.2.11/lib/active_record/connection_adapters/abstract/connection_pool.rb:239:in `checkout'
from /Users/Danny/.rvm/gems/ruby-2.0.0-p195/gems/activerecord-3.2.11/lib/active_record/connection_adapters/abstract/connection_pool.rb:102:in `block in connection'
from /Users/Danny/.rvm/rubies/ruby-2.0.0-p195/lib/ruby/2.0.0/monitor.rb:211:in `mon_synchronize'
from /Users/Danny/.rvm/gems/ruby-2.0.0-p195/gems/activerecord-3.2.11/lib/active_record/connection_adapters/abstract/connection_pool.rb:101:in `connection'
from /Users/Danny/.rvm/gems/ruby-2.0.0-p195/gems/activerecord-3.2.11/lib/active_record/connection_adapters/abstract/connection_pool.rb:410:in `retrieve_connection'
from /Users/Danny/.rvm/gems/ruby-2.0.0-p195/gems/activerecord-3.2.11/lib/active_record/connection_adapters/abstract/connection_specification.rb:171:in `retrieve_connection'
from /Users/Danny/.rvm/gems/ruby-2.0.0-p195/gems/activerecord-3.2.11/lib/active_record/connection_adapters/abstract/connection_specification.rb:145:in `connection'
from /Users/Danny/.rvm/gems/ruby-2.0.0-p195/gems/activerecord-3.2.11/lib/active_record/model_schema.rb:308:in `clear_cache!'
from /Users/Danny/.rvm/gems/ruby-2.0.0-p195/gems/activerecord-3.2.11/lib/active_record/railtie.rb:97:in `block (2 levels) in <class:Railtie>'
from /Users/Danny/.rvm/gems/ruby-2.0.0-p195/gems/activesupport-3.2.11/lib/active_support/callbacks.rb:418:in `_run__3642716200177086041__prepare__4186317719333288752__callbacks'
from /Users/Danny/.rvm/gems/ruby-2.0.0-p195/gems/activesupport-3.2.11/lib/active_support/callbacks.rb:405:in `__run_callback'
from /Users/Danny/.rvm/gems/ruby-2.0.0-p195/gems/activesupport-3.2.11/lib/active_support/callbacks.rb:385:in `_run_prepare_callbacks'
from /Users/Danny/.rvm/gems/ruby-2.0.0-p195/gems/activesupport-3.2.11/lib/active_support/callbacks.rb:81:in `run_callbacks'
from /Users/Danny/.rvm/gems/ruby-2.0.0-p195/gems/actionpack-3.2.11/lib/action_dispatch/middleware/reloader.rb:74:in `prepare!'
from /Users/Danny/.rvm/gems/ruby-2.0.0-p195/gems/actionpack-3.2.11/lib/action_dispatch/middleware/reloader.rb:48:in `prepare!'
from /Users/Danny/.rvm/gems/ruby-2.0.0-p195/gems/railties-3.2.11/lib/rails/application/finisher.rb:47:in `block in <module:Finisher>'
from /Users/Danny/.rvm/gems/ruby-2.0.0-p195/gems/railties-3.2.11/lib/rails/initializable.rb:30:in `instance_exec'
from /Users/Danny/.rvm/gems/ruby-2.0.0-p195/gems/railties-3.2.11/lib/rails/initializable.rb:30:in `run'
from /Users/Danny/.rvm/gems/ruby-2.0.0-p195/gems/railties-3.2.11/lib/rails/initializable.rb:55:in `block in run_initializers'
from /Users/Danny/.rvm/gems/ruby-2.0.0-p195/gems/railties-3.2.11/lib/rails/initializable.rb:54:in `each'
from /Users/Danny/.rvm/gems/ruby-2.0.0-p195/gems/railties-3.2.11/lib/rails/initializable.rb:54:in `run_initializers'
from /Users/Danny/.rvm/gems/ruby-2.0.0-p195/gems/railties-3.2.11/lib/rails/application.rb:136:in `initialize!'
from /Users/Danny/.rvm/gems/ruby-2.0.0-p195/gems/railties-3.2.11/lib/rails/railtie/configurable.rb:30:in `method_missing'
from /Users/Danny/Dropbox/programming/coding/f_app/config/environment.rb:7:in `<top (required)>'
from /Users/Danny/.rvm/gems/ruby-2.0.0-p195/gems/activesupport-3.2.11/lib/active_support/dependencies.rb:251:in `require'
from /Users/Danny/.rvm/gems/ruby-2.0.0-p195/gems/activesupport-3.2.11/lib/active_support/dependencies.rb:251:in `block in require'
from /Users/Danny/.rvm/gems/ruby-2.0.0-p195/gems/activesupport-3.2.11/lib/active_support/dependencies.rb:236:in `load_dependency'
from /Users/Danny/.rvm/gems/ruby-2.0.0-p195/gems/activesupport-3.2.11/lib/active_support/dependencies.rb:251:in `require'
from /Users/Danny/Dropbox/programming/coding/f_app/config.ru:3:in `block in <main>'
from /Users/Danny/.rvm/gems/ruby-2.0.0-p195/gems/rack-1.4.5/lib/rack/builder.rb:51:in `instance_eval'
from /Users/Danny/.rvm/gems/ruby-2.0.0-p195/gems/rack-1.4.5/lib/rack/builder.rb:51:in `initialize'
from /Users/Danny/Dropbox/programming/coding/f_app/config.ru:in `new'
from /Users/Danny/Dropbox/programming/coding/f_app/config.ru:in `<main>'
from /Users/Danny/.rvm/gems/ruby-2.0.0-p195/gems/rack-1.4.5/lib/rack/builder.rb:40:in `eval'
from /Users/Danny/.rvm/gems/ruby-2.0.0-p195/gems/rack-1.4.5/lib/rack/builder.rb:40:in `parse_file'
from /Users/Danny/.rvm/gems/ruby-2.0.0-p195/gems/rack-1.4.5/lib/rack/server.rb:200:in `app'
from /Users/Danny/.rvm/gems/ruby-2.0.0-p195/gems/railties-3.2.11/lib/rails/commands/server.rb:46:in `app'
from /Users/Danny/.rvm/gems/ruby-2.0.0-p195/gems/rack-1.4.5/lib/rack/server.rb:304:in `wrapped_app'
from /Users/Danny/.rvm/gems/ruby-2.0.0-p195/gems/rack-1.4.5/lib/rack/server.rb:254:in `start'
from /Users/Danny/.rvm/gems/ruby-2.0.0-p195/gems/railties-3.2.11/lib/rails/commands/server.rb:70:in `start'
from /Users/Danny/.rvm/gems/ruby-2.0.0-p195/gems/railties-3.2.11/lib/rails/commands.rb:55:in `block in <top (required)>'
from /Users/Danny/.rvm/gems/ruby-2.0.0-p195/gems/railties-3.2.11/lib/rails/commands.rb:50:in `tap'
from /Users/Danny/.rvm/gems/ruby-2.0.0-p195/gems/railties-3.2.11/lib/rails/commands.rb:50:in `<top (required)>'
from script/rails:6:in `require'
from script/rails:6:in `<main>'

Answer 1

錯誤消息是有用的：

 could not connect to server: Connection refused Is the server running on host "localhost" (::1) and accepting TCP/IP connections on port 5433?

港口

您可能正在嘗試連接到錯誤的端口。
標准端口是5432 。 檢查您是如何（以及是否）啟動您的 postgres 服務器的：

postgres@db:~$ ps -auxww | grep ^postgres
... <stripped more lines>
postgres  1274  0.0  0.3 1437240 57308 ?       S    May27   5:01 /usr/lib/postgresql/9.1/bin/postgres -D /var/lib/postgresql/9.1/main -c config_file=/etc/postgresql/9.1/main/postgresql.conf

手冊在這里有相關信息。

在我的示例中，使用了/etc/postgresql/9.1/main/postgresql.conf設置，其中說（在許多其他設置中）：

port = 5432

或者運行：

netstat -nlp | grep postgres

或者只是看這里（至少在 Debian 或 Ubuntu 中）：

ls -lA /var/run/postgresql/

如果您創建新的數據庫集群，PostgreSQL 會選擇下一個空閑端口。 由於您反復安裝，您可能混淆了端口號。

listen_addresses

或者您只是忘記允許 TCP/IP 連接。 相關回答：

• 使用沒有密碼的 psql 命令運行批處理文件
• pg_hba.conf 中的“本地”和“本地主機”連接類型有什么區別？
• 沒有主機的 pg_hba.conf 條目

Answer 2

這可能會解決問題：-

• 使用命令SHOW config_file;獲取 hba.conf 文件地址SHOW config_file; 和SHOW hba_file; 在 sql 提示符下

• 現在打開hba.conf並將此host all all 0.0.0.0/0 trust添加到host all all 0.0.0.0/0 trust

• 現在打開postgresql.conf並添加listen_address = '*'

Answer 3

就我而言，問題是由 Ubuntu 16.04 中的 postgresql-9.4 升級到 postgresql-9.5 引起的。 由於在某個時間點安裝了兩個版本，后來安裝的版本即 postgresql-9.5 的配置更改為默認端口5433 （而不是標准默認端口5432 ）。

當我的 Rails 項目嘗試連接到 postgresql 的默認端口時出現問題（因為該端口沒有在database.yml文件中明確定義）並且一直失敗。 即使在刪除 postgresql-9.4 之后。

更改 postgresql 配置文件的解決方案

解決方案是在更新的 postgresql (9.5) 的配置中更改端口。 為此，請打開文件/etc/postgresql/9.5/main/postgresql.conf並更改行

port = 5433                             # (change requires restart)

到

port = 5432                             # (change requires restart)

然后使用sudo service postgresql restart服務器。

更改 Rails 的“database.yml”文件的解決方案

或者，您可以通過明確提及新端口（即5433 ）來更改 rails 的database.yml文件，而無需更改 postgresql 的配置文件。 為此，只需添加這樣的一行

port: 5433

並重新啟動 rails 服務器。

Answer 4

sudo -u postgres pg_ctlcluster 9.3 main stop

其次是

sudo -u postgres pg_ctlcluster 9.3 main restart

為我工作

Answer 5

我收到了這條連接到 Jira（從 Jira 端）的錯誤消息，解決方案是更改“數據庫服務器的主機名或 IP 地址”。 到“本地主機”。 如果您在本地運行，則不能只輸入本地 IP 地址。

此外，本地安裝的下一個問題是密碼總是失敗，即使這是正確的，因為 pg_hba.conf 需要編輯，因此身份驗證方法是“信任”。

Answer 6

在 postgresql.conf 中， /var/lib/pgsql/data/postgresql.conf ：

1. 將listen_addresses = 'localhost' to listen_addresses = '*'更改listen_addresses = 'localhost' to listen_addresses = '*'

2. 啟用默認端口為 5432， port = 5432

同樣在 pg_hba.conf, /var/lib/pgsql/data/pg_hba.conf ，嘗試身份驗證方法為 trust