[kreeben]

If you are solely supporting union or solely supporting intersection then roaring bitmaps is probably not a perfect solution to any of your problems.

There are some algorithms that have been optimized for intersect, union, remove (OR, AND, NOT) that work extremely well for sorted lists but the problem is usually: how to efficiently sort the lists that you wish to perform boolean operations on, so that you can then apply the roaring bitmap algorithms on them.

https://roaringbitmap.org/

[marginalia_nu]

Roaring Bitmaps are awesome. I use them when merging indices. I need to know which items to keep from the old index, so I'm calculating the intersection between two sets of a cardinality around 500,000,000. Without breaking a sweat.