"In my head, there has always been a missing piece of software - a "database compiler", that can take the very complex and high-dimensionality abstract specific

"In my head, there has always been a missing piece of software - a "database compiler", that can take the very complex and high-dimensionality abstract specification for a domain and codegen a purpose-built database engine." You nailed it! And this is in fact our design for TigerBeetle, an Iron Man suit that you can put any state machine business logic into. You get global consensus protocol and local storage engine, with all the performance of TigerBeetle, and it's a really nice experience writing your own business logic inside of that. You can even test everything using Deterministic Simulation Testing. Long term, we want to extract this into a library. Reading the TB source, you'll see all these abstractions are something we're thinking about.