Approximate Membership Query Filters with a False Positive Free Set

TL;DR

This paper introduces a new static filter design that guarantees zero false positives for a specified set of negative elements, improving efficiency in approximate membership queries.

Contribution

It proposes a novel class of static filters with zero false positives for certain elements, implemented via xor probing filters, with multiple efficient constructions.

Findings

Memory and speed overheads are often negligible.

The filters effectively eliminate false positives for targeted elements.

Potential practical benefits in various applications.

Abstract

In the last decade, significant efforts have been made to reduce the false positive rate of approximate membership checking structures. This has led to the development of new structures such as cuckoo filters and xor filters. Adaptive filters that can react to false positives as they occur to avoid them for future queries to the same elements have also been recently developed. In this paper, we propose a new type of static filters that completely avoid false positives for a given set of negative elements and show how they can be efficiently implemented using xor probing filters. Several constructions of these filters with a false positive free set are proposed that minimize the memory and speed overheads introduced by avoiding false positives. The proposed filters have been extensively evaluated to validate their functionality and show that in many cases both the memory and speed overheads are negligible. We also discuss several use cases to illustrate the potential benefits of the proposed filters in practical applications.