To take an example close to my heart: Differential dataflow is a dataflow engine that includes support for automatic parallel execution, horizontal scaling and incrementally maintained views. It totals ~16kloc and was mostly written by a single person. Materialize adds support for SQL and various data sources. To date, that has taken ~128kloc (not including dependencies) and I estimate ~15-20 engineer-years. Just converting SQL to the logical plan takes ~27kloc, more than than the entirety of differential dataflow.
Similarly, sqlite looks to have ~212kloc and duckdb ~141kloc. The count for duckdb doesn’t even include the parser that they (sensibly) borrowed from postgres, which at ~47kloc is much larger than the entire ~30kloc codebase for lua.Jamie Brandon – Against SQL