I just upgraded my MacMini Server from Lion Server to Mountain Lion using OS X Server. I am having the same problem with PostgreSQL that I did last year when I first installed Lion Server.
When I try to do any kind of PostgreSQL terminal command I get the following notorious error message that many have gotten over the years:
psql: could not connect to server: No such file or directory
Is the server running locally and accepting
connections on Unix domain socket "/var/pgsql_socket/.s.PGSQL.5432"?
I was attempting to change the password for _postgres when I got the error. I tried several commands but got the same error. I just rebooted my server but no luck. I logged in as root to look at /var/pgsql_socket and the folder is empty. Folder /var/pgsql_socket_alt is also empty.
I have checked online about this. However just about all of the solutions I have read, including on Stack Overflow, suggest a removal and reinstall of PostgreSQL. I do not know but this does not seem like a plausible option because several options on the Server App use PostgreSQL. I contacted Apple Enterprise Support (no agreement) and I was told that my issue would have to be solved by the developers which would cast $695.
I have a website that is down right now because I cannot rebuild it. I don't know where to turn for help with this at this point. I will continue looking online to see if I can find something. However I hope that someone can give me an answer quick so I can rebuild my database.
Update: 12/13/2012 15:33 GMT-6
Here is my output for ps auwwx|grep postg:
_postgres 28123 0.0 0.1 2479696 7724 ?? Ss 3:01PM 0:00.04 /Applications/Server.app/Contents/ServerRoot/usr/bin/postgres_real -D /Library/Server/PostgreSQL For Server Services/Data -c listen_addresses= -c log_connections=on -c log_directory=/Library/Logs/PostgreSQL -c log_filename=PostgreSQL_Server_Services.log -c log_line_prefix=%t -c log_lock_waits=on -c log_statement=ddl -c logging_collector=on -c unix_socket_directory=/Library/Server/PostgreSQL For Server Services/Socket -c unix_socket_group=_postgres -c unix_socket_permissions=0770
server1 28216 0.0 0.0 2432768 620 s000 R+ 3:02PM 0:00.00 grep postg
_postgres 28138 0.0 0.0 2439388 752 ?? Ss 3:01PM 0:00.01 postgres: stats collector process
_postgres 28137 0.0 0.0 2479828 1968 ?? Ss 3:01PM 0:00.00 postgres: autovacuum launcher process
_postgres 28136 0.0 0.0 2479696 544 ?? Ss 3:01PM 0:00.00 postgres: wal writer process
_postgres 28135 0.0 0.0 2479696 732 ?? Ss 3:01PM 0:00.01 postgres: writer process
_postgres 28134 0.0 0.0 2479696 592 ?? Ss 3:01PM 0:00.00 postgres: checkpointer process
_postgres 28131 0.0 0.0 2439388 368 ?? Ss 3:01PM 0:00.00 postgres: logger process
Update: 12/13/2012 18:10 GMT-6
After intense web searching this video was found. I was able to get PostgreSQL working and remove the error. I am able to connect using pgadmin and phppgadmin. I was about to go back to Lion Server because of sheer frustration. Now I will not have to.
I was able to add the following to my .bash_profile to prevent the error:
export PGHOST=localhost
This works because:
If you omit the host name, psql will connect via a Unix-domain socket to a server on the local host, or via TCP/IP to localhost on machines that don't have Unix-domain sockets.
Your OS supports Unix domain sockets, but PostgreSQL's Unix socket that psql needs either doesn't exist or is in a different location than it expects.
Specifying a hostname explicitly as localhost forces psql to use TCP/IP. Setting an environment variable PGHOST is one of the ways to achieve that. It's documented in psql's manual.
Try paste in console this:
$ mkdir /var/pgsql_socket/
$ ln -s /private/tmp/.s.PGSQL.5432 /var/pgsql_socket/
I was able to solve by simply filling in 127.0.0.1 for the PostgreSQL host address rather than leaving it blank. (Django Example)
DATABASES = {
'default': {
'ENGINE': 'django.db.backends.postgresql_psycopg2',
'NAME': 'database_name',
'USER': 'database_user',
'PASSWORD': 'pass',
'HOST': '127.0.0.1',
'PORT': '',
}
}
Open 'postgresql.conf' in you favourite editor. Look for the variable 'unix_socket_directories', it will most likely look like this:
unix_socket_directories = '/private/tmp/'
Change the line to this:
unix_socket_directories = '/var/pgsql_socket/'
Note if you want the socket files in more than one directory comma separate them.
As mentioned by others in the comments, a really simple solution to this issue is to declare the database 'host' within the database configuration. Adding this answer just to make it a little more clear for anyone reading this.
In a Ruby on Rails app for example, edit /config/database.yml:
development:
adapter: postgresql
encoding: unicode
database: database_name
pool: 5
host: localhost
Note: the last line added to specify the host. Prior to updating to Yosemite I never needed to specify the host in this way.
Hope this helps someone.
Cheers
A much more simple solution (thanks to http://daniel.fone.net.nz/blog/2014/12/01/fixing-connection-errors-after-upgrading-postgres/) . I had upgraded to postgres 9.4. In my case, all I needed to do (after a day of googling and not succeeding)
gem uninstall pg
gem uninstall activerecord-postgresql-adapter
bundle install
Restart webrick, and done!
Check for the status of the database:
service postgresql status
If the database is not running, start the db:
sudo service postgresql start
Can you check your postgresql.conf file ??
On what port your postgres is running ??
I think it is not running on port 5432.If not change it to 5432
OR on terminal use
psql -U postgres -p YOUR_PORT_NUMBER database_name
I had this problem with Django.
Fix it by explicitly setting your hostname to "localhost".
i make in word by doing this:
dpkg-reconfigure locales
and choose your preferred locales
pg_createcluster 9.5 main --start
(9.5 is my version of postgresql)
/etc/init.d/postgresql start
and then it word!
sudo su - postgres
psql
If you have the above problem but you have upgraded from Yosemite, then a different approach is needed as the upgrade solution can destroy some files. More details are at `pg_tblspc` missing after installation of latest version of OS X (Yosemite or El Capitan).
apt-get install postgres-xc-client
apt-get install postgres-xc
psql: could not connect to server: No such file or directory
Is the server running locally and accepting
connections on Unix domain socket"/var/pgsql_socket/.s.PGSQL.5432"?
I kept on getting the above error and none of the above solutions worked for me. Finally the following solution solved my problem on Mac OS X
Install postgres using brew
brew install postgres
Install brew services
brew tap homebrew/services
To start postgres as a background service
brew services start postgresql
To stop postgres manually
brew services stop postgresql
We can also use brew services to restart Postgres
brew services restart postgresql
check the postgres server is running with following code
sudo service postgresql status
if the postgres server is inactive, write the following command.
sudo service postgresql start
File permissions are restrictive on the Postgres db owned by the Mac OS. These permissions are reset after reboot, or restart of Postgres: e.g. serveradmin start postgres.
So, temporarily reset the permissions or ownership:
sudo chmod o+rwx /var/pgsql_socket/.s.PGSQL.5432
sudo chown "webUser" /var/pgsql_socket/.s.PGSQL.5432
Permissions resetting is not secure, so install a version of the db that you own for a solution.
It took me a while but I was able to get this working finally after going through the suggestions offered and additional web searches being done. I used the information in the following YouTube video created by Mactasia:
http://www.youtube.com/watch?v=y1c7WFMMkZ4
When I did this I saw the file with .lock as the extension. However I still got the error when I tried to start the Rails Server when I resumed working on my Rails application using PostgreSQL. This time I got a permission denied error. This is when I remembered that not only did I have to change listen_addresses in the plist but I also had to change unit_socket_permissions to 0777. I also logged in as root to change the permissions on the var/pgsql_socket folder where I could access it at the user level. Postgres is working fine now. I am in the process of reloading my data from my SQL backup.
What I did not understand was that when I had wiki turned on PostgreSQL was supposedly working when I did a sudo serveradmin fullstatus postgres but I still got the error. Oh well.
I just created a new cluster and that worked for me, I was using (PostgreSQL) 9.3.20:
sudo pg_createcluster 9.3 main --start
First remove the installed postgres:
sudo apt-get purge postgr*
sudo apt-get autoremove
Then install 'synaptic':
sudo apt-get install synaptic
sudo apt-get update
Then install Postgres
sudo apt-get install postgresql postgresql-contrib
I got this error after my computer froze and rebooted on its own. The solution for me was not found on this page, rather on another very highly rated SO question with the same error psql: could not connect to server: No such file or directory (Mac OS X). The answer: just delete this file /usr/local/var/postgres/postmaster.pid, then brew services restart postgresql did the trick. Heed the warning on the linked answer about killing postgres processes before doing this else you could corrupt your db permanently.
来源：https://stackoverflow.com/questions/13868730/socket-file-var-pgsql-socket-s-pgsql-5432-missing-in-mountain-lion-os-x-ser