Hoo.st is using now, the high performance database, MariaDB.
MariaDB is a community-developed fork of the MySQL relational database management system, the impetus being the community maintenance of its free status under the GNU GPL. As a fork of a leading open source software system, it is notable for being led by its original developers and triggered by concerns over direction by an acquiring commercial company Oracle. Contributors are required to share their copyright with Monty Program AB.
The intent is also to maintain high compatibility with MySQL, ensuring a “drop-in” replacement capability with library binary equivalency and exact matching with MySQL APIs and commands. It includes the XtraDB storage engine as a replacement for InnoDB, as well as a new storage engine, Aria, that intends to be both a transactional and non-transactional engine perhaps even included in future versions of MySQL.
Its lead developer is Michael “Monty” Widenius, the founder of MySQL and Monty Program AB. He had previously sold his company, MySQL AB, to Sun Microsystems for 1 billion USD. MariaDB is named after Monty’s younger daughter, Maria.