Introduction
PostgreSQL is an object-relational database management system (ORDBMS) developed at the University of California at Berkeley Computer Science Department.
It supports a large part of the SQL standard and offers many modern features:
- complex queries
- foreign keys
- triggers
- updateable views
- transactional integrity
- multiversion concurrency control
Also, PostgreSQL can be extended by the user in many ways, for example by adding new:
- data types
- functions
- operators
- aggregate functions
- index methods
- procedural languages
And because of the liberal license, PostgreSQL can be used, modified, and distributed free of charge by anyone for any purpose, be it private, commercial, or academic.
These features have consolidated the engine in the top 4 of the most used databases.
Figure 1: PostgreSQL Rank
PostgreSQL offers natively some of the most industry demanded feature, such as master-slave replication, backup and recovery, transactionality, partitioning.
Anyway, there are still some other demanded features that need to be accomplished by external tools, such as sharding, master-master setups, monitoring, load balancing and statistics reporting.