Sun closed on its acquisition of MySQL today, calling the billion-dollar purchase the “most important acquisition in Sun’s history” – oh, heck, make that the “modern software industry” – with Sun preening that it completed the deal in less than six weeks convinced that it is now a proven open source leader ready to hustle platforms into the “Network Economy.”

Although Sun figures it’s plucked the star off the top of Christmas tree, the “M” in LAMP, it’s still in the market for other “tuck-in” open source acquisitions, reckoning that it’s a “natural home to a lot of them,” well, at least those with “high-integrity communities, broad distribution and some measure of commercial success.”

MySQL is going to form the basis of a new database group in Sun’s software division and former MySQL CEO Marten Mickos is going to stick around and run it reporting to software division capo Rich Green.

Existing projects like MySQL’s own Falcon storage engine and Sun’s interests in Postgres, as well as MySQL’s partnerships with such as Dell, HP, IBM, Microsoft, Red Hat and Zend, are supposed to continue merrily on.

MySQL’s only problem as an independent company, according to Sun, was its inability to provide 7x24 enterprise-class support globally, a deficit Sun is now ready to compensate for – for a flat annual fee, something it calls MySQL Enterprise Unlimited, which is supposed to help customers deploy and manage an unlimited number of MySQL servers (see www.mysql.com/unlimited).

And Sun will be throwing its whole 17,000-strong sales and service organization at it.

Unfortunately perhaps, given Sun’s track record in delivering promised software, it’s promising to accelerate MySQL’s product roadmap, spurring it to new levels of performance and scaling.

Sun’s delirium over buying MySQL – for a heady price given Sun’s performance since the dot.com bust – comes from MySQL’s customer base, described by Sun CEO Jonathan Schwartz as being in the “tens of million,” even if there really are only maybe 12 million instances installed.

Schwartz sees these unmonetized, unused downloads as a “profoundly important opportunity for Sun,” which, he says, now has a shot at the $15 billion database market and is a natural for Web 2.0 plays, the YouTube, Facebook, Google generation.

He’s also counting on moving Solaris-based hardware on the back on MySQL. See, MySQL was the missing piece of Sun’s “platform for the network.” It now has an open source operating system, office suite, development tools and a database.

“For the first time ever,” he said in a canned quote repeated on a conference all, “businesses across world can standardize on a commercially supported, open source platform” for mission-critical use.

Sun says MySQL downloads have jump from 50,000 a day to 60,000 since Sun’s acquisition of the company was announced. MySQL brings with it penetration in SaaS, telecom and embedded, Sun noted.

Schwartz is in complete denial about Sun now competing with touchy established database players like Oracle jealous of their business.

Anyway, to get the ball rolling, Sun has free downloads of all MySQL products available at www.sun.com/mysql/download and free trial subscriptions at www.sun/com/mysql/trial.