So what are the advantages over adaptive radix trees or good old judy-dict/array?<p>Apart from judy being too damn complicated, and too old to be optimized for vector-compare instructions (I think the fancy hand-coded x86 vector-comparisons are the main reason for ART being competitive with judy, considering that it misses at least key compression and the clever allocator, and that ART is not as optimized for using every byte out of every fetched cache-line).