If you're interested in query compilation, check out the HyPer DBMS prototype at [1]. It efficiently compiles SQL (SQL92++) to super-fast LLVM code (faster than Vitesse). It's not open source, but you can download a binary [4] or try it out online using the "WebInterface" link and read about the query compiler here [2]. It also has lots of other goodies, like SIMD-powered CSV parsing (about 4x faster than Postgres) [3].
Rumor has it that the prototype will be commercialized soon ;)
EDIT: It also has NUMA-aware multi-threaded query execution.
Looks like the Vitesse product was inspired by this research. Even though the HyPer looks a lot more mature (though it's still a research project). Looking forward to see the product.
EDIT: It also has NUMA-aware multi-threaded query execution.
[1] http://www.hyper-db.com
[2] http://www.vldb.org/pvldb/vol4/p539-neumann.pdf
[3] http://www.vldb.org/pvldb/vol6/p1702-muehlbauer.pdf
[4] http://databasearchitects.blogspot.de/2014/05/trying-out-hyp...