So there are plenty of systems that compile portions of a SQL plan to bytecode (LLVM or JVM) or machine code directly. Usually, the part you compile is the SQL

So there are plenty of systems that compile portions of a SQL plan to bytecode (LLVM or JVM) or machine code directly. Usually, the part you compile is the SQL plan and most importantly the predicate filters. Common operations like networking, transaction management and even index walks (except the key comparisons) are already compiled to native code, so you don't need to go all in. You just optimize the stuff that needs it.