Oracle MySQL
See the following -
How Percona Has Built a Successful Open Source Business Based on Support and Services Revenues
By Peter Zaitsev | October 10, 2016
The open source community is a diverse and fractious collection of individuals and organizations. In its infancy, in many ways it could be compared to the hippie movements of the '60s: a lot of passion, a lot of fun, a lot of weirdness, and not a lot of organization. Over the last decade or so, it has evolved into a respected software development force that relies on the support of its members. As it's grown and diversified over the last decade, it has gotten more mainstream in the sense that there are now many different players that are making quite a bit of money based on open source principles. It has more prestige and a lot more respectability. As they say, money changes everything...