The object-relational database management system now known as PostgreSQL is derived from the
POSTGRES package written at the University of California at Berkeley. With over two decades
of development behind it, PostgreSQL is now the most advanced open-source database available
anywhere.
2.1. The Berkeley POSTGRES Project
The POSTGRES project, led by Professor Michael Stonebraker, was sponsored by the Defense
Advanced Research Projects Agency (DARPA), the Army Research Office (ARO), the National
Science Foundation (NSF), and ESL, Inc. The implementation of POSTGRES began in 1986. The
initial concepts for the system were presented in [ston86], and the definition of the initial data model
appeared in [rowe87]. The design of the rule system at that time was described in [ston87a]. The
rationale and architecture of the storage manager were detailed in [ston87b].
POSTGRES has undergone several major releases since then. The first “demoware” system became
operational in 1987 and was shown at the 1988 ACM-SIGMOD Conference. Version 1, described in
[ston90a], was released to a few external users in June 1989. In response to a critique of the first rule
system ([ston89]), the rule system was redesigned ([ston90b]), and Version 2 was released in June
1990 with the new rule system. Version 3 appeared in 1991 and added support for multiple storage
managers, an improved query executor, and a rewritten rule system. For the most part, subsequent
releases until Postgres95 (see below) focused on portability and reliability.
POSTGRES has been used to implement many different research and production applications. These
include: a financial data analysis system, a jet engine performance monitoring package, an asteroid
tracking database, a medical information database, and several geographic information systems.
POSTGRES has also been used as an educational tool at several universities. Finally, Illustra
Information Technologies (later merged into Informix2 , which is now owned by IBM3 ) picked up
the code and commercialized it. In late 1992, POSTGRES became the primary data manager for the
Sequoia 2000 scientific computing project4.
The size of the external user community nearly doubled during 1993. It became increasingly obvious
that maintenance of the prototype code and support was taking up large amounts of time that should
have been devoted to database research. In an effort to reduce this support burden, the Berkeley
POSTGRES project officially ended with Version 4.2.
