PostgreSQL is a free object-relational database system.


Install PostgreSQL:

emerge -a postgresql

Setup PostgresSQL:

emerge --config postgresql
Configuring pkg...

 * You can modify the paths and options passed to initdb by editing:
 *     /etc/conf.d/postgresql-10
 * Information on options that can be passed to initdb are found at:
 * PG_INITDB_OPTS is currently set to:
 *     --encoding=UTF8
 * Configuration files will be installed to:
 *     /etc/postgresql-10/
 * The database cluster will be created in:
 *     /var/lib/postgresql/10/data
 * Continuing initialization in 5 seconds (Control-C to cancel) ...
 [ ok ]
 * Creating the data directory ...
 * Initializing the database ...
The files belonging to this database system will be owned by user "postgres".
This user must also own the server process.

The database cluster will be initialized with locales
  COLLATE:  en_US.utf8
  CTYPE:    en_US.utf8
  MESSAGES: en_US.utf8
  MONETARY: en_US.utf8
  TIME:     en_US.utf8
The default text search configuration will be set to "english".

Data page checksums are disabled.

fixing permissions on existing directory /var/lib/postgresql/10/data ... ok
creating subdirectories ... ok
selecting default max_connections ... 100
selecting default shared_buffers ... 128MB
selecting dynamic shared memory implementation ... posix
creating configuration files ... ok
running bootstrap script ... ok
performing post-bootstrap initialization ... ok
syncing data to disk ... ok

WARNING: enabling "trust" authentication for local connections
You can change this by editing pg_hba.conf or using the option -A, or
--auth-local and --auth-host, the next time you run initdb.

Success. You can now start the database server using:

    /usr/lib64/postgresql-10/bin/pg_ctl -D /var/lib/postgresql/10/data -l logfile start

 * The autovacuum function, which was in contrib, has been moved to the main
 * PostgreSQL functions starting with 8.1, and starting with 8.4 is now enabled
 * by default. You can disable it in the cluster's:
 *     /etc/postgresql-10/postgresql.conf
 * The PostgreSQL server, by default, will log events to:
 *     /var/lib/postgresql/10/data/postmaster.log
 * You should use the '/etc/init.d/postgresql-10' script to run PostgreSQL
 * instead of 'pg_ctl'.

The output above contains the main information.

Start PostgreSQL:

/etc/init.d/postgresql-10 start
postgresql-10 | * /run/postgresql: creating directory
postgresql-10 | * /run/postgresql: correcting owner
postgresql-10 | * Starting PostgreSQL 10 ...                                 [ ok ]

Add the SQL server to autostart:

rc-update add postgresql-10
 * service postgresql-10 added to runlevel default

Postgres user configuration

Set a password for the postgres user:

psql -U postgres

psql (10.3)
Type "help" for help.
postgres=# \password
Enter new password:
Enter it again:
postgres=# \q

Database access configuration

Configure the access to the SQL server, so that local calls only be allowed, originated from the local network


# TYPE  DATABASE        USER            ADDRESS                 METHOD
# "local" is for Unix domain socket connections only
local   all             all                                     password
# IPv4 local connections:
host    all             all               password
host    all             all             password
# IPv6 local connections:
#host   all             all             ::1/128                 trust
# Allow replication connections from localhost, by a user with the
# replication privilege.
#local  replication     all                                     trust
#host   replication     all               trust
#host   replication     all             ::1/128                 trust

Specify IP addresses to be listened to by the PostgreSQL, comma-separated:



# - Connection Settings -

listen_addresses = ',' # what IP address(es) to listen on;
                                           # comma-separated list of addresses;
                                           # defaults to 'localhost'; use '*' for all
                                           # (change requires restart)


If the server needs to be accessed from all network interfaces, set "*" instead of IPs.

Restart the database server:

/etc/init.d/postgresql-10 restart
postgresql-10 | * Stopping PostgreSQL 10 (this can take up to 92 seconds) ... [ ok ]
postgresql-10 | * /run/postgresql: correcting mode
postgresql-10 | * Starting PostgreSQL 10 ...                                  [ ok ]

Check for operating ports:

netstat -an
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address           Foreign Address         State      
tcp        0      0    *               LISTEN     
tcp        0      0*               LISTEN     
tcp        0      0*               LISTEN     
tcp6       0      0 :::22                   :::*                    LISTEN     
udp        0      0         ESTABLISHED
Active UNIX domain sockets (servers and established)
Proto RefCnt Flags       Type       State         I-Node   Path
unix  2      [ ACC ]     STREAM     LISTENING     281718   /run/postgresql/.s.PGSQL.5432

Exampe: create a database and a database user

Let's create a database, called dbtest and a user, called test to work with it:

psql -U postgres

Password for user postgres:
psql (10.3)
Type "help" for help.

postgres=# create database dbtest;
postgres=# create role test with login;
postgres=# \password test
Enter new password: 
Enter it again: 
postgres=# grant connect, create on database dbtest to test;
postgres=# \l dbtest
                               List of databases
  Name  |  Owner   | Encoding |  Collate   |   Ctype    |   Access privileges   
 dbtest | postgres | UTF8     | en_US.utf8 | en_US.utf8 | =Tc/postgres         +
        |          |          |            |            | postgres=CTc/postgres+
        |          |          |            |            | test=Cc/postgres
(1 row)

postgres=# \q

The database and the database user have been created.

You can now check the user:

psql -U test -d dbtest
Password for user test: 
psql (10.3)
Type "help" for help.

test=> \q