Chapter 1. About PostgreSQL

PostgreSQL is an object-relational database management system (DBMS). Its initial implementation started in 1986, and PostgreSQL is now the world's most advanced Open Source database system available. PostgreSQL's predecessor was Ingres, a database developed at the University of California at Berkeley (1977 “1985). From 1986 to 1994, Michael Stonebraker led a team that focused on the development of an object-relational database server called Postgres ( post is the Latin word for after; PostgreSQL came after Ingres). The code was then taken by Illustra and developed into a commercial product.

Illustra Information Technologies merged with Informix, which is now a global player in the database business (in 2001, Informix was bought by IBM).

The developement of Postgres officially ended with version 4.2 in 1994, because the maintenance of such large amounts of code took too much time ”time that should have been devoted to database research.

Two graduates of Berkeley, Jolly Chen and Andrew Yu, added SQL support to PostgreSQL in 1994 and 1995. This project was called Postgres95. Chen and Yu left Berkeley, but Chen continued maintaining and developing Postgres95. Even an active mailing list existed.

Postgres95 was completely implemented in ANSI C and had some major enhancements beyond Postgres 4.2, such as a GNU readline interface, a TCL frontend, and support for GROUP BY clauses.

A team was formed to continue the development. Jolly Chen stated: "This code needs a few people with lots of time, not many people with a little time." At that time the source code included about 250,000 lines of C code; it seems that Chen was right.

The core development team consisted of four people: Marc Fournier in Canada, Thomas Lockhart in Pasadena (California), Vadim Mikheev in Krasnoyarsk (Russia), and Bruce Momjian in Philadelphia (Pennsylvania).

In late 1996, it became obvious that Postgres95 was not the right name for a database of the future, and PostgreSQL was chosen . PostgreSQL reflects the relationship between the old Postgres system and the SQL capabilities of PostgreSQL. The version number was set to 6.0, which represented the real number in the sequence of PostgreSQL development.

The main target for the PostgreSQL developers was to enhance PostgreSQL and to add new features:

• The locking system (only table locking was implemented at that time) was replaced with multiversion concurrency control.

• Datatypes for geometric operation were added.

• The speed of the backend was increased significantly.

• ANSI SQL92 features were added.

• Subselects, triggers, defaults, and constraints were implemented.

More than a dozen developers are currently working on PostgreSQL, and the number of PostgreSQL users is constantly growing around the globe.