PostgreSQL (often referred to as Postgres) is an open source object-relational database management system with a particular focus on extensibility and standards compliance. It is a highly used and tested solution having started in 1981 as the Ingres project at the University of California. The project was later named Postgres as it became "post Ingres", and then in 1996 the online presence at the website PostgreSQL.org was launched while the project was renamed PostgreSQL to reflect its support for SQL.
The first PostgreSQL release was known as version 6.0 on January 29, 1997 and since then PostgreSQL has continued to be developed by the PostgreSQL Global Development Group, a diverse group of companies and many thousands of individual contributors. As an open source solution, it is free and released under the terms of the PostgreSQL License, a permissive software license.
The PostgreSQL project continues to make major releases (approximately annually) and minor bug fix releases, all available under its free and open-source software PostgreSQL License. It can handle workloads ranging from small single-machine applications to large Internet-facing applications with many concurrent users.
PostgreSQL runs on all major operating systems including Linux, UNIX variants, and Windows, and is fully ACID-compliant, with full support for foreign keys, joins, views, triggers, and stored procedures (in multiple languages).
As an enterprise-class database, PostgreSQL boasts features such as:
- Multi-Version Concurrency Control (MVCC)
- point-in-time recovery
- asynchronous replication
- nested transactions (savepoints)
- online/hot backups
- sophisticated query planner/optimizer, and
- write ahead logging for fault tolerance.
It also supports international character sets, multibyte character encodings, Unicode, and is locale-aware for sorting, case-sensitivity, and formatting.
PostgreSQL is highly scalable both in the sheer quantity of data it can manage and in the number of concurrent users it can accommodate. There are active PostgreSQL systems in production environments that manage in excess of 4 TB of data.
You can read more about PostgreSQL at www.postgresql.org/about.