If you suspect there's something wrong with our database (cluster), make a copy of your database directory before you continue. Just to be sure. On Ubuntu the default directory would be: /var/lib/postgresql/9.3/main/ - but your installation may differ.
Actually, your command should work (in default Ubuntu installations), because the service command starts the postgres server process with appropriate privileges (as system user postgres)
sudo service postgresql start
Translates to something like:
sudo -u postgres /usr/lib/postgresql/9.3/bin/pg_ctl -D /var/lib/postgresql/9.3/main/ -o "-c config_file=/etc/postgresql/9.3/main/postgresql.conf" start
That starts all db clusters you may have. To start a particular one, use the wrapper pg_ctlcluster:
sudo -u postgres pg_ctlcluster 9.3 main start
To get the status of all currently installed db clusters use pg_lsclusters:
sudo -u postgres pg_lsclusters
You must be aware that the data directory is not the same as the config directory in default Debian or Ubuntu Postgres installations. For Postgres 9.3 that would be:
data dir: /var/lib/postgresql/9.3/main/
config dir: /etc/postgresql/9.3/main/
You can check the /etc/postgresql/9.3/main/postgrsql.conf for the actual data dir. It's the line starting with
data_directory =
The error message indicates that Postgres tries to start with the default data dir, but it is not there or the privileges have been changed. Did you check?
Or are you running a non-default installation?
Best Answer
psqlassumes that you want to connect to a database, you can either provide one (just after the command) or it will assume you want to connect to a database whose name is the same as your username (or the account name of the process that startedpsql):So, you could write:
or
or yet
... and
psqlwill connect to the (local) database namedmy_db.You have more connection options that you can check in the documentation.
If you don't have yet a database created, check
createdb.