Chapter 1. What is PostgreSQL?

Table of Contents
Open Source Free Version
PostgreSQL Feature Set
Where to Proceed from Here

PostgreSQL is an Object-Relational Database Management System (ORDBMS) that has been developed in various forms since 1977. It began as a project named Ingres at the University of California at Berkeley. Ingres itself was later developed commercially by Relational Technologies/Ingres Corporation.

In 1986 another team led by Michael Stonebraker from Berkeley continued the development of the Ingres code to create an object-relational database system called Postgres. In 1996, due to a new open source effort and the enhanced functionality of the software, Postgres was renamed to PostgreSQL, after a brief stint as Postgres95. The PostgreSQL project is still under very active development worldwide from a team of open source developers and contributors.

PostgreSQL is widely considered to be the most advanced open source database system in the world. It provides many features (which are discussed in more detail in "PostgreSQL Feature Set") that are traditionally seen only in enterprise-caliber commercial products.

Open Source Free Version

PostgreSQL is an open source project. Open source by definition means that you can obtain the source code, use the program, and modify it freely without the confines of proprietary software. In the database world, open source means that you have honest access to benchmarking numbers and performance statistics, which companies such as Oracle prohibit. Open source also means that you are free to modify PostgreSQL to fit your particular needs.

However, there is a misconception that since open source software is free from distribution restrictions, it is always free of cost to your company. This is not necessarily the case. It is true that you can, without external cost, download and install open source software, but there will always be costs associated with the time and energy your company puts into support and research of the application. As such, if you do not have those resources to spend, there are several commercial vendors and consultants who deal specifically with PostgreSQL.

Commercial PostgreSQL Products

The Red Hat version of PostgreSQL is called Red Hat Database and is a very new product to the database market. The Red Hat Database is based on the community-released open source version, PostgreSQL 7.1. Red Hat Database currently supports Linux only, preferably Red Hat Linux 7.1.

Open Source Versus Commercial Products

The open source version of PostgreSQL only includes the database-management system and the associated programming interfaces. The Great Bridge and Red Hat versions of PostgreSQL each include a graphical installer and limited support for the installation.

The main factor in deciding whether to use the open source version of PostgreSQL or one of the commercially available versions should be your business requirements. If you have a knowledgeable on-site technical-support staff, the community version may do well for you. However, if you need installation, configuration, and management support, you may be better served by purchasing a commercial version of PostgreSQL.

If you prefer to do business with smaller consulting companies, we have compiled a modest list of professional companies providing support for PostgreSQL in "Commercial Support."

The Bottom Line

Marketing would suggest that the commercial versions of PostgreSQL are somehow objectively superior to the open source versions of PostgreSQL. In reality, this is not the case. When deciding what version of PostgreSQL you are going to run, you need only be aware of your own needs. For example, are you going to need installation support? Is a graphical installation important to you? If they are, then you should probably purchase a commercial version of PostgreSQL. However, if you or one of your staff are comfortable with compiling and configuring source code, the open source version could be more applicable to you.

There are two additional questions you may want to ask. Do you need printed documentation and are you willing to pay for PostgreSQL? Both of the commercial distributions come with printed documentation. However, if you are reading this book, we hope you won't need the additional documentation. The other question relates to cost. Great Bridge PostgreSQL, as of August 2001, is priced at $495.00. The Red Hat Database is priced at $2,295.00.

The most important thing to remember when deciding on which version of PostgreSQL to use is this (from a perspective of general usage and feature availability): there is no practical difference between the open source and the commercial versions.

Commercial Support

Outside of Red Hat, there are many companies that provide consulting services to the PostgreSQL community. The following is a small list of consultants providing commercial support for PostgreSQL.

Command Prompt, Inc. (

Command Prompt, Inc. is a Linux managed-services and PostgreSQL-support company. They provide Linux and PostgreSQL support, including custom programming PostgreSQL, C++, PHP, Perl, and their own LXP application server for PostgreSQL.

Command Prompt, Inc. is the author of this book.

Cybertec Geschwinde & Schvnig OEG (

Cybertec provides training courses, support, consulting, and cost-effective high-end systems. Cybertec services the German-speaking region (Austria, Germany, and Switzerland).

dbExperts (

dbExperts offers training courses, specialized support for development, and commercial products for PostgreSQL. dbExperts is located in Brazil and provides services in the Portuguese language.

PostgreSQL, Inc. (

PostgreSQL, Inc. offers support for PostgreSQL, database hosting, and promotional materials.

Software Research Associates (

Software Research Associates offers a range of services to aid customers with open source software-based systems. Support from this company is also available in Japanese.

Community Support

The PostgreSQL community provides active support to users of PostgreSQL via a number of mailing lists. There are several user mailing lists to which you can subscribe, segregated by topic (e.g., pgsql-general, pgsql-hackers, etc). The mailing lists for PostgreSQL users are quite thorough, covering everything from general discussion to support on developing with PostgreSQL programming interfaces. For a complete list of mailing lists with associated descriptions, please visit the PostgreSQL website at