Psql could not connect to server: No such file or

Question

I'm trying to run psql on my Vagrant machine, but I get this 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"?

Note: Vagrant 1.9.2 Box: ubuntu/trusty64, https://atlas.hashicorp.com/ubuntu/boxes/trusty64

EDIT Commands I've used in order to install and run postgres:

• sudo apt-get update
• sudo apt-get install postgresql
• sudo su postgres
• psql -d postgres -U postgres

Answer 1

I had the same error when I create the SQL db in a VM. I had changed the default value of /etc/postgresql/9.3/main/postgresql.conf shared_buffers = 200MB to 75% of my total RAM. Well, I forgot to actually allocate that RAM in the VM. When I gave the command to make a new database, I received the same error.

Powered off, gave the baby its bottle (RAM) and presto, it worked.

Answer 2

I got this error when I restored my database from last pg_basebackup backup file. After that when I tried to connect database(psql), I was getting the same error. The error was resolved, when I updated pg_hba.conf file and wherever "peer" authentication was there I replaced that with "md5" and then restarted postgres services. After that, the problem was resolved.

Answer 3

This works for me:

pg_ctl -D /usr/local/var/postgresql@9.6 stop;
brew services stop postgresql@9.6;
brew services start postgresql@9.6;

Answer 4

just reinstall your pgsql with direct version sudo apt-get install postgresql-9.5 (u must remove the package before install new one)