Is the server running locally and accepting connections on Unix domain socket “/var/run/postgresql/.s.PGSQL.5432”? in Odoo - postgresql

Question

After some time the Postgres database stopped working of my live server. I'm working on this server from last 8 months. Now suddenly it's stopped working.
when I try to enter the command, psql produces an error
psql: could not connect to server: No such file or directory
Is the server running locally and accepting
connections on Unix domain socket "/var/run/postgresql/.s.PGSQL.5432"?
enter image description here
I'm using odoo8.

Answer 1

First, you need to make sure the socket file is located in /var/run/postgresql/.s.PGSQL.5432. To check that
$ cat /var/run/postgresql/.s.PGSQL.5432
if result shows something, then the problem is anything else. But, if file is not there you need to check /tmp dir (specially for OSX Homebrew users)
$ cd /tmp
$ l
total 16
drwxrwxrwt 7 root wheel 224B Mar 11 08:03 .
drwxr-xr-x 6 root wheel 192B Jan 23 18:35 ..
-rw-r--r-- 1 root wheel 65B Nov 7 22:59 .BBE72B41371180178E084EEAF106AED4F350939DB95D3516864A1CC62E7AE82F
srwxrwxrwx 1 shiva wheel 0B Mar 11 08:03 .s.PGSQL.5432
-rw------- 1 shiva wheel 57B Mar 11 08:03 .s.PGSQL.5432.lock
drwx------ 3 shiva wheel 96B Mar 10 17:11 com.apple.launchd.C1tUB2MvF8
drwxr-xr-x 2 root wheel 64B Mar 10 17:10 powerlog
Now, there are two ways you can solve the error
Solution One
You can change the application configuration to see for sockets at /tmp/.s.PGSQL.5432
For Rails Users
# config/database.yml
default: &default
adapter: postgresql
pool: 5
# port:
timeout: 5000
encoding: utf8
# min_messages: warning
socket: /tmp/.s.PGSQL.5432
Solution Two
You can create symlinks to the expected location
$ sudo mkdir /var/pgsql_socket
$ sudo ln /tmp/.s.PGSQL.5432 /var/pgsql_socket/
Then the error should go.
Hope this helps.
Note: Your default socket directory may not be /tmp

Answer 2

Did you update/upgrade your database?
Did you start a docker container that interfered with any of your data-store/socket file locations?
This probably doesn't fit your situation exactly, but maybe it will provide some insight:
Sometimes when you try
sudo systemctl start postgresql.service
and the systemd status says it is started but you still get that error message when trying to connect, try this instead:
sudo pg_ctlcluster <version> <cluster> <action>
which in my case had been
sudo pg_ctlcluster 13 main start