In Chapter 1, we discussed the history of MySQL’s acquisition by Sun Microsystems, then Sun’s acquisition by Oracle Corporation, and how the server has fared through these stewardship changes. But there is much more to the story. MySQL isn’t available solely from Oracle anymore. In the process of two acquisitions, several variants of MySQL appeared. Although most users are unlikely to want anything but the “official” version of MySQL from Oracle, the variants are genuinely important and have made a big difference to all MySQL users—even those who would never consider using them.

There have been a handful of MySQL variants over the years, but three major variants have stood the test of time so far. These three are Percona Server, MariaDB, and Drizzle. All of them have active user communities and some degree of commercial backing. All are supported by independent service providers.