Sun's US$1 billion play for the Swedish open source database vendor MySQL AB is a deft move, and a dangerous one.

It's deft because it exploits a trend toward open source software and Web-based, online applications. It's dangerous because this "Web economy," as Sun CEO Jonathan Schwartz dubs it, is also the prime hunting ground for Oracle, IBM, and especially Microsoft. Sun and MySQL have sidestepped the traditional database market to jump feet first into the emerging one.

They're likely to be welcomed there. MySQL is generally regarded as the most successful of the open source databases, which also include EnterpriseDB (based on the PostgreSQL code base), Firebird (built on the venerable InterBase code), Apache Derby, the Sleepycat embedded database (bought by Oracle in 2006) and Greenplum (which last year announced $15 million in new venture funding and a new CEO, a 19-year veteran of Sun).

Users like these databases because they typically are very fast, especially in read-only applications, have no or nominal licensing fees, and are cheap to run and administer. Their use in an array of enterprise applications has been growing steadily. 

"I didn't feel the need to spend money on something that worked fine, from the open source community," says Lance Obermeyer, CTO for Digby, an Austin, Texas software company that offers a mobile e-shopping application and service, based on MySQL. "We had no qualms about using an open source product. It can be just as good as the commercial database."

Narrowing the feature gap

While all the open source databases lack the vast wealth of features found on Oracle, DB2, and even Microsoft SQL Server -- products that were designed a generation ago -- the gap lessens with each successive iteration.

MySQL 5.0, the current release, was issued in 2006 as the company's initial foray into the data center. The database uses a modular architecture so that different storage engines (from MySQL or community members) can be plugged into the core database functions.

Currently, for example, MySLQ has two existing plug-ins for transaction processing: the InnoDB engine (acquired by Oracle a few years ago), and the company's own MySQLCluster. An alpha version of MySQL's new Falcon transaction processing plug-in is available now, with a beta version due out soon. Falcon is designed for large-memory, multithreaded, and multi-CPU applications such as high-volume Web sites, according to MySQL. Falcon architect Jim Starkey talked about his work in a November interview. 

These kinds of advances, coupled with Sun's global customer and tech support, will make MySQL more palatable to high-end enterprise sites, where today Oracle, IBM and Microsoft together own 85% of a $15 billion market, according to several analysts.

But neither Sun nor MySQL executives expect anyone to rip out their clustered Oracle 11g database and replace it with MySQL. Instead, they're aiming at new and emerging Web-based, online applications, where MySQL already has a solid presence and a blue chip customer list, including Yahoo, Facebook and Google.

At Yahoo, for example, MySQL quickly handles vast amounts of data from hundreds of daily news feeds. In response to the mouse clicks by Yahoo visitors, MySQL stores, marks up and posts the data in Web pages.

For these companies, and many like them, the software framework undergirding online applications is the open source software stack called LAMP, named for the Linux operating system, Apache Web server, MySQL database, and PHP scripting language.

Sun sees LAMP as the basis for a new generation of Web-based, service-oriented software architectures taking root in the enterprise. "We're putting a billion dollars behind this open source stack," says Rich Green, executive vice