The concept behind this talk is basically just trying to understand database implementations and compilers better through the lens of an actual production implementation. Everyone uses databases in various forms, but few of us know how they are actually implemented. This talk goes through everything from the broad ideas and architecture all the way down to the implementation of data structures, algorithms, and optimizations to make all of it fast. It also serves as a decent introduction to how exactly you can structure a large, production Scala project written in a purely functional style, and all of the ways to make that code fast on the JVM. If you're interested in compilers, data structures, databases, performance optimization, recursion schemes, graph theory, formal meta-theories of set manipulation algebras, or even just making fun of my Scala indentation style, you will enjoy this talk!