I used to work at a small-ish (but very profitable) European company whose "crown jewel", in terms of in-house developed technology, was a distributed in-memory

I used to work at a small-ish (but very profitable) European company whose "crown jewel", in terms of in-house developed technology, was a distributed in-memory search/database engine, written in hand-crafted, multi-threaded C by a true coding wizard and industry veteran. It used Judy arrays at its heart for the very first filtering/processing stage of queries, and did so to amazing effect. It's quite spectacular what you could and can do with libjudy if you use it wisely :) I always wondered if relatively recent changes in x86 CPU µarchs broke some of the assumptions that made libjudy perform this great even on Pentium-class hardware, and if the de facto only complete implementation (that I happen to be aware of) could be improved as a consequence, if those changes (i.e., hugely increased cache sizes, etc.) were considered.