Yes. Swiss is good for non-duplicate lookups. For highly duplicate data the extra memory fetch for the metadata byte really kills the performance. For this con

Yes. Swiss is good for non-duplicate lookups. For highly duplicate data the extra memory fetch for the metadata byte really kills the performance. For this contest, there’re a billion lookups with only couple hundreds distinct keys. That means for most lookups, the full path of locating the key is executed - hashing, metadata comparison, hashed value comparison, and full key comparison. It’s actually quite expensive. Removing any part from the execution path really helps.