Mar 15, 2025

The other approach I’ve looked at is more like a Cuckoo filter, where there is a hash function result stored in the header bucket. This takes advantage of the pre-filtering by hashmap bucket. For a single 32 byte hash result, using key data independent of the hashmap hash function, it is also very inefficient, since probability of matching independent conflicts with a bucket is very low. The filter is applied to the first element in the list (and any other that matches it, which is 1 in 2^32 and no others. So false positives are around 1 in 2.5.