Why is CodeQL so fast and have such excellent performance?

[Raindragon-abc]

I am deeply interested in the underlying mechanics of CodeQL's internal DIL (Datalog Intermediate Language) optimizations. Prior to this, I’ve gained foundational knowledge of query rewriting techniques in Soufflé(another open-source Datalog engine), I am also familiar with some simple optimizations item such as join order.
I am particularly interested in learning which specific optimization passes CodeQL employs on its DIL representation. Furthermore, among these, which top 3–5 optimizations optimizations yield the most significant performance gains in practice？
Sincerely appreciate any of your responses and assistance.

[smowton]

I recommend taking a look at the QL academic publications (https://codeql.github.com/publications/), which give an overview of the CodeQL datalog implementation and some of the more noteworthy optimisations used.