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<!-- doc/src/sgml/history.sgml -->
<sect1 id="history">
<title>A Brief History of <productname>PostgreSQL</productname></title>
<indexterm zone="history">
<primary>history</primary>
<secondary>of PostgreSQL</secondary>
</indexterm>
<para>
The object-relational database management system now known as
<productname>PostgreSQL</productname> is derived from the
<productname>POSTGRES</productname> package written at the
University of California at Berkeley. With decades of
development behind it, <productname>PostgreSQL</productname> is now
the most advanced open-source database available anywhere.
</para>
<sect2 id="history-berkeley">
<title>The Berkeley <productname>POSTGRES</productname> Project</title>
<indexterm zone="history-berkeley">
<primary>POSTGRES</primary>
</indexterm>
<para>
The <productname>POSTGRES</productname> project, led by Professor
Michael Stonebraker, was sponsored by the Defense Advanced Research
Projects Agency (<acronym>DARPA</acronym>), the Army Research
Office (<acronym>ARO</acronym>), the National Science Foundation
(<acronym>NSF</acronym>), and ESL, Inc. The implementation of
<productname>POSTGRES</productname> began in 1986. The initial
concepts for the system were presented in <xref linkend="ston86"/>,
and the definition of the initial data model appeared in <xref
linkend="rowe87"/>. The design of the rule system at that time was
described in <xref linkend="ston87a"/>. The rationale and
architecture of the storage manager were detailed in <xref
linkend="ston87b"/>.
</para>
<para>
<productname>POSTGRES</productname> has undergone several major
releases since then. The first <quote>demoware</quote> system
became operational in 1987 and was shown at the 1988
<acronym>ACM-SIGMOD</acronym> Conference. Version 1, described in
<xref linkend="ston90a"/>, was released to a few external users in
June 1989. In response to a critique of the first rule system
(<xref linkend="ston89"/>), the rule system was redesigned (<xref
linkend="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 <productname>Postgres95</productname> (see below) focused on
portability and reliability.
</para>
<para>
<productname>POSTGRES</productname> 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.
<productname>POSTGRES</productname> has also been used as an
educational tool at several universities. Finally, Illustra
Information Technologies (later merged into
<ulink url="https://www.ibm.com/analytics/informix"><productname>Informix</productname></ulink>,
which is now owned by <ulink
url="https://www.ibm.com/">IBM</ulink>) picked up the code and
commercialized it. In late 1992,
<productname>POSTGRES</productname> became the primary data manager
for the
<ulink url="http://meteora.ucsd.edu/s2k/s2k_home.html">
Sequoia 2000 scientific computing project</ulink>.
</para>
<para>
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
<productname>POSTGRES</productname> project officially ended with
Version 4.2.
</para>
</sect2>
<sect2 id="history-postgres95">
<title><productname>Postgres95</productname></title>
<indexterm zone="history-postgres95">
<primary>Postgres95</primary>
</indexterm>
<para>
In 1994, Andrew Yu and Jolly Chen added an SQL language interpreter
to <productname>POSTGRES</productname>. Under a new name,
<productname>Postgres95</productname> was subsequently released to
the web to find its own way in the world as an open-source
descendant of the original <productname>POSTGRES</productname>
Berkeley code.
</para>
<para>
<productname>Postgres95</productname> code was completely ANSI C
and trimmed in size by 25%. Many internal changes improved
performance and
maintainability. <productname>Postgres95</productname> release
1.0.x ran about 30–50% faster on the Wisconsin Benchmark compared
to <productname>POSTGRES</productname>, Version 4.2. Apart from
bug fixes, the following were the major enhancements:
<itemizedlist>
<listitem>
<para>
The query language PostQUEL was replaced with
<acronym>SQL</acronym> (implemented in the server). (Interface
library <link linkend="libpq">libpq</link> was named after PostQUEL.)
Subqueries
were not supported until <productname>PostgreSQL</productname>
(see below), but they could be imitated in
<productname>Postgres95</productname> with user-defined
<acronym>SQL</acronym> functions. Aggregate functions were
re-implemented. Support for the <literal>GROUP BY</literal>
query clause was also added.
</para>
</listitem>
<listitem>
<para>
A new program
(<application>psql</application>) was provided for interactive
SQL queries, which used <acronym>GNU</acronym>
<application>Readline</application>. This largely superseded
the old <application>monitor</application> program.
</para>
</listitem>
<listitem>
<para>
A new front-end library, <filename>libpgtcl</filename>,
supported <acronym>Tcl</acronym>-based clients. A sample shell,
<command>pgtclsh</command>, provided new Tcl commands to
interface <application>Tcl</application> programs with the
<productname>Postgres95</productname> server.
</para>
</listitem>
<listitem>
<para>
The large-object interface was overhauled. The inversion large
objects were the only mechanism for storing large objects. (The
inversion file system was removed.)
</para>
</listitem>
<listitem>
<para>
The instance-level rule system was removed. Rules were still
available as rewrite rules.
</para>
</listitem>
<listitem>
<para>
A short tutorial introducing regular <acronym>SQL</acronym>
features as well as those of
<productname>Postgres95</productname> was distributed with the
source code
</para>
</listitem>
<listitem>
<para>
<acronym>GNU</acronym> make (instead of <acronym>BSD</acronym>
make) was used for the build. Also,
<productname>Postgres95</productname> could be compiled with an
unpatched <productname>GCC</productname> (data alignment of
doubles was fixed).
</para>
</listitem>
</itemizedlist>
</para>
</sect2>
<sect2>
<title><productname>PostgreSQL</productname></title>
<para>
By 1996, it became clear that the name <quote>Postgres95</quote>
would not stand the test of time. We chose a new name,
<productname>PostgreSQL</productname>, to reflect the relationship
between the original <productname>POSTGRES</productname> and the
more recent versions with <acronym>SQL</acronym> capability. At
the same time, we set the version numbering to start at 6.0,
putting the numbers back into the sequence originally begun by the
Berkeley <productname>POSTGRES</productname> project.
</para>
<para>
Many people continue to refer to
<productname>PostgreSQL</productname> as <quote>Postgres</quote>
(now rarely in all capital letters) because of tradition or because
it is easier to pronounce. This usage is widely accepted as a
nickname or alias.
</para>
<para>
The emphasis during development of
<productname>Postgres95</productname> was on identifying and
understanding existing problems in the server code. With
<productname>PostgreSQL</productname>, the emphasis has shifted to
augmenting features and capabilities, although work continues in
all areas.
</para>
<para>
Details about what has happened in <productname>PostgreSQL</productname> since
then can be found in <xref linkend="release"/>.
</para>
</sect2>
</sect1>
|
