[InooDB Diagrams](https://github.com/jeremycole/innodb_diagrams) is a brilliant project that helped many people in understanding basics of InnoDB, I'd assume it's best project out there to learn InnoDB inside data structures. Jeremy Cole explained how he created the InnoDB diagrams and motive behind it in here: "[On learning InnoDB: A journey to the core](https://blog.jcole.us/2013/01/02/on-learning-innodb-a-journey-to-the-core/)" It's a short summary of that blog post. Motivation behind creating those diagrams: - He believes InnoDB documentation was pretty lacking in clear explanations of InnoDB’s internal data structures - InnoDB code is too much complex, you should be hopeful to say 'I Understood the data structures and intent behind them' just by reading the code. His approach to understanding complex poorly documented codes: - Read whatever exist, code and documents. - Write your own implementations, preferably in a complete different language. It will help you to think and revise everything. - Create new documentation and diagram based on your acquired knowledge in this journey, update your previous wrong understanding documentations. - Repeat it until correct. Finally he created that project based on this approach.