I am thrilled to be celebrate Percona's 15th anniversary. My time with MySQL began about the same time as the founding of Percona. Those years, the mid-2000s, were the dark ages for MySQL. There was doubt about the future of MySQL because there were many things that needed to be made better. Fortunately, upstream and the community, with much help from Percona, rallied to fix the problems and add needed features.
Percona has been a huge part of the community. I don't have time to list everything, but examples include saving the user conference, providing an open-source hot backup solution, educating many of us (including me) via their blog posts and helping push the product to get so much better. I have also been a customer as they helped with the MyRocks effort and in the great patch migration (5.6 to 8.0).
I like that the anniversary book starts by mentioning the multi-core scaling problem that InnoDB had in the mid-2000s. My MySQL deployment used 4-core, 1-socket CPUs at the time and 8-core, 2-socket servers were about to arrive. It was difficult to get more than 10k QPS from MySQL/InnoDB on such hardware regardless of the number of cores or sockets. InnoDB didn't benefit from 2-socket servers because of contention in the custom InnoDB mutex (which was also used to guard state in the custom InnoDB rw-lock). A fix was first proposed by Yasufumi Kinoshita, who would soon join Percona. After seeing his presentation at the user conference, my team at Google proposed a similar solution which was accepted by the InnoDB team and a serious problem was resolved.
I also like that the book is full of stories from people in the community. I know many of these people from my time traveling to conferences. I am an introvert except when at conferences. I rarely observe talks because I am out in the hallway track talking to others.