To the faithful, Oracle's acquisition of key MySQL partner Innobase is proof of what they've believed all along: MySQL's success is a threat to Oracle's database business and it's only a matter of time before the two companies collide.
Early on, MySQL's developers did a very clever thing. They designed it in such a way that the code for storing and managing database tables was modular. That made it possible for MySQL to support multiple table types, including ones contributed by third-party vendors like Innobase.
The default table type for MySQL, called MyISAM, is very fast but doesn't meet the requirements of the enterprise. Innobase's InnoDB table type takes steps in that direction, however, by providing MySQL with a transaction-safe storage engine. InnoDB now comes bundled with MySQL, beginning with the beta releases of version 5.0. Many observers feel that the features it brings are essential to MySQL's evolution and continued success.
That's why when Oracle snapped up Innobase in early October it was easy to interpret the move as a major offensive on Oracle's part -- by taking control of one of MySQL's vital internal organs, Oracle gains the power to crush the upstart at a whim, simply by closing its grip around Innobase.
By acquiring Innobase, however, Oracle gains three things. One, it gains accurate accounting of MySQL's market share (because InnoDB ships with every copy). Two, and more importantly, it gains access to the list of MySQL customers who need InnoDB support -- in other words, those specific customers who want the enterprise-class features Oracle has provided for years. And finally, by owning the InnoDB code, Oracle will be in a unique position to develop easy tools to let customers migrate from MySQL to Oracle when the time comes.
So why kill InnoDB or MySQL? I think Oracle has long recognized that what's good for MySQL is good for the relational database market as a whole.
Now, in the wake of the Innobase acquisition, MySQL may have become the best sales tool Oracle's database division has.