Discussing Google's move, engineer Jeremy Cole stated that while his company "[values] stability and performance over fancy new features. Oracle doesn’t always feel the same way." Cole also accused Oracle of "[ignoring] bugs, feedback, and communication from the [MySQL] community." Google is said to have "thousands" of modified MySQL instances running across its servers.
Developers have already been arguing MariaDB offers better performance than MySQL, and that Oracle is slow to address bugs and security issues. There have also been complaints Oracle is undermining MySQL's open-source nature via proprietary modules.
Ever since Oracle announced it would be acquiring Sun (and with it, MySQL), the company has been dogged by accusations owning both the most popular open-source database and the most popular proprietary database (responsible for billions in annual profits) presents a huge conflict of interest. At the time of the deal, Oracle promised EU regulators it would keep actively supporting MySQL.