Ruby-on-rails 服务器是否在主机“localhost”(::1) 上运行并接受端口 5432 上的 TCP/IP 连接？

Is the server running on host "localhost" (::1) and accepting TCP/IP connections on port 5432?

提问by Thibaud Clement

Before anything, please note that I have found several similar questions on Stack Overflow and articles all over the web, but none of those helped me fix my issue:

在此之前，请注意，我在 Stack Overflow 和网络上的文章中发现了几个类似的问题，但这些问题都没有帮助我解决问题：

• PG Error could not connect to server: Connection refused Is the server running on port 5432?
• PG::ConnectionBad - could not connect to server: Connection refused
• psql: could not connect to server: Connection refused

• PG 错误无法连接到服务器：连接被拒绝 服务器是否在端口 5432 上运行？
• PG::ConnectionBad - 无法连接到服务器：连接被拒绝
• psql：无法连接到服务器：连接被拒绝

Now, here is the issue:

现在，这里是问题：

• I have a Rails app that works like a charm.
• With my collaborator, we use GitHub to work together.
• We have a masterand an mvpbranches.
• I recently updated my gitversion with Homebrew (Mac).
• We use Foreman to start our app locally.

• 我有一个非常棒的 Rails 应用程序。
• 与我的合作者一起，我们使用 GitHub 一起工作。
• 我们有一个master和一个mvp分支。
• 我最近git用 Homebrew (Mac)更新了我的版本。
• 我们使用 Foreman 在本地启动我们的应用程序。

Now, when I try to launch the app locally, I get the following error:

现在，当我尝试在本地启动应用程序时，出现以下错误：

PG::ConnectionBad at /
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?

I tried to reboot my computers several times.

我多次尝试重新启动计算机。

I also checked the content of /usr/local/var/postgres:

我还检查了以下内容/usr/local/var/postgres：

PG_VERSION      pg_dynshmem     pg_multixact    pg_snapshots    pg_tblspc       postgresql.conf
base            pg_hba.conf     pg_notify       pg_stat         pg_twophase     postmaster.opts
global          pg_ident.conf   pg_replslot     pg_stat_tmp     pg_xlog         server.log
pg_clog         pg_logical      pg_serial       pg_subtrans     postgresql.auto.conf

As you can see, there is no postmaster.pidfile in there.

如您所见，那里没有postmaster.pid文件。

Any idea how I could fix this?

知道我该如何解决这个问题吗？

采纳答案by Graham Slick

You most likely ran out of battery and your postgresql server didn't shutdown correctly.

您很可能没电了，并且您的 postgresql 服务器没有正确关闭。

The easiest workaround is to download the official postgresql app and launch it: it will force the server to start (http://postgresapp.com/)

最简单的解决方法是下载官方 postgresql 应用程序并启动它：它会强制服务器启动（http://postgresapp.com/）

回答by user8376606

run postgres -D /usr/local/var/postgresand you should see something like:

运行 postgres -D /usr/local/var/postgres，您应该会看到如下内容：

 FATAL:  lock file "postmaster.pid" already exists
 HINT:   Is another postmaster (PID 379) running in data directory "/usr/local/var/postgres"?

Then run kill -9 PIDin HINT

然后kill -9 PID在 HINT 中运行

And you should be good to go.

你应该很高兴去。

回答by Nishant

Most likely it's because your system shutdown unexpectedly

很可能是因为您的系统意外关闭

Try

尝试

postgres -D /usr/local/var/postgres

You might see

你可能会看到

FATAL:  lock file "postmaster.pid" already exists
HINT:  Is another postmaster (PID 449) running in data directory "/usr/local/var/postgres"?

FATAL:  lock file "postmaster.pid" already exists
HINT:  Is another postmaster (PID 449) running in data directory "/usr/local/var/postgres"?

Then try

然后试试

kill -9 PID

example

例子

kill -9 419

And it should start postgres normally

它应该正常启动 postgres

回答by Shiva89

It might be as simple as the postgresql service is down. Try running:

可能就像 postgresql 服务关闭一样简单。尝试运行：

sudo service postgresql start

which fixed the issue for me.

这为我解决了这个问题。

回答by Tan

This worked in my case:

这在我的情况下有效：

brew uninstall postgresql
rm -fr /usr/local/var/postgres/
brew install postgresql

回答by Talha Meh

I had almost just as same error with my Ruby on Rails application running postgresql(mac). This worked for me:

我的 Ruby on Rails 应用程序在运行 postgresql(mac) 时遇到了几乎同样的错误。这对我有用：

brew services restart postgresql

回答by Aman Kumar

This can be as pid file created for postgress have not been deleted due to unexpected shutdown. So to fix this, remove this pid file.

这可能是因为为 postgress 创建的 pid 文件由于意外关闭而没有被删除。因此，要解决此问题，请删除此 pid 文件。

1. Find the postgres data directory. On a MAC using homebrew it is /usr/local/var/postgres/, other systems it might be /usr/var/postgres/

2. Remove pid file

   rm postmaster.pid

3. Restart postgress. On Mac,

   brew services restart postgresql

1. 找到 postgres 数据目录。在使用自制软件的 MAC 上/usr/local/var/postgres/，它可能是其他系统/usr/var/postgres/

2. 删除pid文件

   rm postmaster.pid

3. 重新启动 postgress。在 Mac 上，

   brew 服务重启 postgresql

回答by techdreams

I resolved the issue via this command

我通过这个命令解决了这个问题

pg_ctl -D /usr/local/var/postgres start

At times, you might get this error

有时，您可能会收到此错误

pg_ctl: another server might be running; trying to start server anyway

So, try running the following command and then run the first command given above.

因此，尝试运行以下命令，然后运行上面给出的第一个命令。

pg_ctl -D /usr/local/var/postgres stop

回答by Tomasz Bartkowiak

For Dockerusers: In my case it was caused by excessive docker image size. You can remove unused data using prunecommand:

对于Docker用户：在我的情况下，它是由过大的Docker图像大小引起的。您可以使用prune命令删除未使用的数据：

docker system prune --all --force --volumes

Warning:as per manual (docker system prune --help):

警告：根据手册 ( docker system prune --help)：

This will remove:

• all stopped containers
• all networks not used by at least one container
• all dangling images
• all dangling build cache

这将删除：

• 所有停止的容器
• 至少一个容器未使用的所有网络
• 所有悬垂的图像
• 所有悬空构建缓存

回答by sogu

It also gives the same error if you just stop your PostgreSQL app. You just need to start it again. (PostgreSQL 11)

如果您只是停止 PostgreSQL 应用程序，它也会出现相同的错误。你只需要重新开始。(PostgreSQL 11)