MariaDB
MariaDB is a community-developed RDBMS (relational database management system). It is a fork of MySQL, designed to be a drop-in replacement for MySQL in most applications. Originally forked by former MySQL developer Michael Widenius due to concerns about MySQL's acquisition by Oracle, the first version of MariaDB was released on October 29, 2009.
MariaDB is highly compatible with MySQL. For most applications that require MySQL, MariaDB can be used instead, with minimal changes to the code.
MariaDB is used internally by companies, including Google, Mozilla, and the Wikimedia Foundation. Also, it's the default database included with the Unix-like operating systems Ubuntu, Debian, Arch Linux, Fedora, RHEL (Red Hat Enterprise Linux), CentOS, OpenSUSE, OpenBSD, and FreeBSD.
In cloud applications, MariaDB is supported by Amazon Web Services, Microsoft Azure, and Alibaba Cloud. It's also available on MariaDB's cloud service, SkySQL.