Instancia

A continuación se dan los pasos básicos para crear una instancia del SGBD PostgreSQL:

1. Crea un cluster de base de datos de PostgreSQL:

   [root@servidor ~]# su - postgres
   [postgres@servidor ~]$ initdb -D /var/lib/pgsql/9.4/data
   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:  C
     CTYPE:    en_US.UTF-8
     MESSAGES: en_US.UTF-8
     MONETARY: en_US.UTF-8
     NUMERIC:  en_US.UTF-8
     TIME:     en_US.UTF-8
   The default database encoding has accordingly been set to "UTF8".
   The default text search configuration will be set to "english".
   
   Data page checksums are disabled.
   
   fixing permissions on existing directory /var/lib/pgsql/9.4/data ... ok
   creating subdirectories ... ok
   selecting default max_connections ... 100
   selecting default shared_buffers ... 128MB
   creating configuration files ... ok
   creating template1 database in /var/lib/pgsql/9.4/data/base/1 ... ok
   initializing pg_authid ... ok
   initializing dependencies ... ok
   creating system views ... ok
   loading system objects' descriptions ... ok
   creating collations ... ok
   creating conversions ... ok
   creating dictionaries ... ok
   setting privileges on built-in objects ... ok
   creating information schema ... ok
   loading PL/pgSQL server-side language ... ok
   vacuuming database template1 ... ok
   copying template1 to template0 ... ok
   copying template1 to postgres ... 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:
   
      postgres -D /var/lib/pgsql/9.4/data/
   or
      pg_ctl -D /var/lib/pgsql/9.4/data/ -l logfile start
   

2. Inicia el demonio de PostgreSQL de forma manual:

   [root@servidor ~]# sh /etc/rc.d/rc.postgresql start
   Starting PostgreSQL
   waiting for server to start.... done
   server started
   

3. Corroba su ejecución:

   [root@servidor ~]#  netstat -plutn
   Active Internet connections (only servers)
   Proto Recv-Q Send-Q Local Address           Foreign Address         State       PID/Program name
   tcp        0      0 127.0.0.1:5432          0.0.0.0:*               LISTEN      659/postgres
   

4. Permite el acceso remoto (desde cualquier host en la red) al usuario postgres:

   4.1. Asigna una contraseña al usuario postgres:

   [root@servidor ~]# su - postgres
   postgres$  psql
   psql (9.4.0)
   Type "help" for help.
   postgres=# \password
   Enter new password: 1q2w
   Enter it again: 1q2w
   postgres=# \q
   

   4.2. Edita el archivo /var/lib/pgsql/9.4/data/postgresql.conf y cambia la línea:

   #listen_addresses = 'localhost'          # what IP address(es) to listen on;
   

   por:

   listen_addresses = '*'          # what IP address(es) to listen on;
   

   4.3. Edita /var/lib/pgsql/9.4/data/pg_hba.conf y agrega al final la siguiente línea:

   host    all             postgres         all                    md5
   

   4.4. Reinicia al demonio de PostgreSQL y verifica su ejecución en red:

   [root@servidor ~]# sh /etc/rc.d/rc.postgresql restart
   Restarting PostgreSQL...
   waiting for server to shut down.... done
   server stopped
   server starting
   [root@servidor ~]# netstat -plutn
   Active Internet connections (only servers)
   Proto Recv-Q Send-Q Local Address           Foreign Address         State       PID/Program name
   tcp        0      0 0.0.0.0:5432            0.0.0.0:*               LISTEN      721/postgres
   

Finalmente, para detener de forma manual al demonio de PostgreSQL ejecuta como root:

[root@servidor ~]# sh /etc/rc.d/rc.postgresql stop
Shutting down PostgreSQL...
waiting for server to shut down.... done
server stopped