What We Found When We Analysed MongoDB's Codebase
One developer. 161 files. The highest churn rate in the entire repository. This is not a startup with three engineers and no processes. This is MongoDB — one of the most widely used, most professionally maintained open-source codebases in the world. Thousands of contributors. Years of accumulated engineering discipline. And still: a single person holds exclusive knowledge of 161 files in a module that changes more than any other. Why MongoDB? We chose MongoDB deliberately. Not because it is a cautionary tale, but because it is the opposite: a project that does almost everything right. Structured contribution guidelines, active code review, long-term maintainers. If knowledge risk shows up here, it shows up everywhere. ...