If the has were really looked up by value, like in the example SQL: SELECT pk, hash, file_path FROM image_hashes WHERE hash = '4c8e3366c275650f'; Th

If the has were really looked up by value, like in the example SQL: SELECT pk, hash, file_path FROM image_hashes WHERE hash = '4c8e3366c275650f'; This is screaming to be stored in a bloom filter.