The dynamic cuckoo filter

The emergence of large-scale dynamic sets in real applications creates stringent requirements for approximate set representation structures: 1) the capacity of the set representation structures should support flexibly extending or reducing to cope with dynamically changing of set size; 2) the set representation structures should support reliable delete operation. Existing techniques for approximate set representation, e.g., the cuckoo filter, the Bloom filter and its variants cannot meet both the requirements of a dynamic set. To solve the problem, in this paper we propose the dynamic cuckoo filter (DCF) to support reliable delete operation and elastic capacity for dynamic set representation and membership testing. Two factors contribute to the efficiency of the DCF design. First, the data structure of a DCF is extendable, making the representation of a dynamic set space efficient. Second, a DCF utilizes a monopolistic fingerprint for representing an item and guarantees reliable delete operation. Experiment results show that compared to the existing state-of-the-art designs, DCF achieves 75% reduction in memory cost, 50% improvement in construction speed, and 80% improvement in speed of membership query. We implement a prototype file backup system and use DCF for data deduplication. Comprehensive experiment results demonstrate the efficiency of our DCF design compared to existing schemes.