What is it?
Sun may own
MySQL, but the company has put more resources into integrating
the rival open source database
PostgreSQL into its Solaris operating system.
Traditionally PostgreSQL has been regarded as the heavyweight of
the two, the Oracle equivalent, in contrast to the cheap and
cheerful, SQL Server-like MySQL. PostgreSQL has been the choice for
on line transaction processing, MySQL for websites.
PostgreSQL had the reputation of performing poorly in web
applications, which was blamed on its feature-heaviness, but
performance has improved dramatically in recent releases.
PostgreSQL is also available in two commercial implementations
which emphasise its mission-critical capabilities: Greenplum's
massively parallel version for data warehousing, and
EnterpriseDB's Oracle
clone Postgres Plus, which claims 99.99 per cent availability.
IBM and NTT are major investors in EnterpriseDB. The Postgres
version of SQL, PL/pgSQL, has always been similar to Oracle's
PL/SQL, and the PostgreSQL team and supporting companies have been
pushing PostgreSQL to Oracle migration for years.
Even with 24/7 commercial support from Sun, Unisys and other
service companies, PostgreSQL can be rolled out at a fraction of
the cost of Oracle. Once other factors such as tools and skills
availability are included, the cost advantage is less clear,
however, and Gartner Group suggests
that "total cost of ownership" of open source databases may still
be higher than their commercial equivalents.
Where did it originate?
Michael Stonebraker, creator of Ingres, began work on Postgres
in 1986 at UC Berkeley, California. An early commercial version of
Postgres, Illustra, became part of the Informix Universal
Server.
What is it for?
PostgreSQL's "enterprise-class" features include a query
optimiser (also recently added by Sun to MySQL), Multi-Version
Concurrency Control, point-in-time recovery, asynchronous
replication and hot backups. As well as its own PL/pgSQL,
PostgreSQL can run stored procedures in Java, C/C++, Perl, Python,
Ruby and Tcl. PostgreSQL includes a framework allowing developers
to define and create their own custom data types along with
supporting functions and operators that define their behaviour.
PostgreSQL 8.3, which became generally available last spring, added
ANSI standard SQL/XML support.
For administrators, there are a number of graphical alternatives
to the psql command line, including phpPgAdmin, based on an
interface written for MySQL.
Sun has optimised PostgreSQL to take advantage of Solaris
technologies such as native DTrace Probes, Solaris Containers
(which allow Linux and other applications to run on Solaris), and
predictive self-healing.
What makes it special?
According to analyst Robin Bloor, 2008 was the year that
petabyte databases became manageable. Bloor says Greenplum, based
on the PostgreSQL engine, is "architected for the petabyte world
and can load data at a speed above 4.5 terabytes per hour - which
is neat, given that it doesn't just write the data to disk, but
actually organises it to enable fast queries".
How difficult is it to master?
You will need a good grasp of SQL. There are two-day retraining
courses for experienced DBAs.
Where is it used?
Major users include BASF, Yahoo, Skype and NTT. PostgreSQL is
widely used in the public sector in the US and across Europe.
What systems does it run on?
Linux, all major versions of Unix, Mac OSX, and a recent port to
Windows with Visual C++ compilation.
What's coming up?
A community-driven PostgreSQL skills certication project is
under way.
Rates of pay
Developers and DBAs earn £25,000 to £45,000.
Training
For free resources start
here, or for
PostgreSQL on Solaris, see
here.