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josefcullhed | 4 years ago

We are currently just doing an intersection and then we make a lookup in a forward index to get the urls, titles and snippets.

I actually don't know what roaring bitmaps are, please enlighten me :)

discuss

order

kreeben|4 years ago

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|4 years ago

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.