Benchmarking beats random ideas, no doubt about that! Thanks for pointing out my mistake with integers. However, I would say Judy doesn't look so hot for string

Benchmarking beats random ideas, no doubt about that! Thanks for pointing out my mistake with integers. However, I would say Judy doesn't look so hot for string keys - slower at most things and similar memory requirements. I'd be interested to see 10 million 64-bit integers in Judy and DenseHash though. Since ten million is 0.2% of 2^32, in some sense lots of the potential key space is actually in use, so I'd expect a lot of sharing to be possible and a sparse trie to perform well. Is there a 64-bit integer key Judy array you could test on?