Some useful links to explain the concepts of PostgreSQl
- http://www.postgresql.org/docs/9.3/static/high-availability.html
- http://www.uptimemadeeasy.com/databases/centos-install-postgres-9-3/
- http://tecadmin.net/install-postgresql-on-centos-rhel-and-fedora/
- http://www.davidghedini.com/pg/entry/install_postgresql_9_on_centos
- https://chartio.com/resources/tutorials/how-to-list-databases-and-tables-in-postgresql-using-psql
- http://www.thegeekstuff.com/2009/04/15-practical-postgresql-database-adminstration-commands/
- https://launchschool.com/blog/how-to-install-postgres-for-linux
- https://www.digitalocean.com/community/tutorials/how-to-use-roles-and-manage-grant-permissions-in-postgresql-on-a-vps--2
- http://www.hack.net.br/2015/02/24/postgresql-replication-with-slony/
- https://www.howtoforge.com/configuring-slony-i-cascading-replication-on-postgresql-8.3
- https://opensourcedbms.com/dbms/setup-replication-with-postgres-9-2-on-centos-6redhat-el6fedora/
- http://www.linuxjournal.com/article/7834?page=0,0
- http://raghavt.blogspot.in/2012/07/simple-slony-i-replication-setup.html
- https://miceliux.com/blog/2013/02/09/postgresql-replication-with-slony/
- https://www.digitalocean.com/community/tutorials/how-to-secure-postgresql-against-automated-attacks
- https://spapas.github.io/2016/11/02/postgresql-backup/