# Cuckoo Filters: Cache-Friendly Membership Checks With Deletions

DevFeed: [Cuckoo Filters: Cache-Friendly Membership Checks With Deletions](<https://devfeed.tech/articles/cuckoo-filters-cache-friendly-membership-checks-with-deletions-39568.md>)

Original publisher: [Read original article](<https://ankit-rana.com/logs/16-cuckoo-filters-architecture/>)

Author: hello@ankit-rana.com

Published: 2026-03-17T00:00:00Z

Content type: tutorial

Language: en

Sources: [Ankit Rana | Mechanical Sympathy](<https://devfeed.tech/sources/ankit-rana-mechanical-sympathy.md>)

Topics: [CPU Cache](<https://devfeed.tech/topics/cpu-cache.md>), [Caching](<https://devfeed.tech/topics/caching.md>), [hash](<https://devfeed.tech/topics/hash.md>)

Tags: [cache](<https://devfeed.tech/tags/cache.md>), [capacity](<https://devfeed.tech/tags/capacity.md>), [cpu-cache](<https://devfeed.tech/tags/cpu-cache.md>), [cuckoo-filter](<https://devfeed.tech/tags/cuckoo-filter.md>), [data-structures](<https://devfeed.tech/tags/data-structures.md>), [false-positive](<https://devfeed.tech/tags/false-positive.md>), [hash](<https://devfeed.tech/tags/hash.md>), [insert](<https://devfeed.tech/tags/insert.md>), [performance](<https://devfeed.tech/tags/performance.md>), [probabilistic](<https://devfeed.tech/tags/probabilistic.md>), [spatial-locality](<https://devfeed.tech/tags/spatial-locality.md>), [systems](<https://devfeed.tech/tags/systems.md>)

## AI overview

This article explains how Cuckoo filters support deletions while improving CPU cache behavior compared with counting Bloom filters. They check two specific buckets using compact fingerprints, but insertions can fail when kick-out chains exceed their limit, requiring capacity planning or overflow handling.

## Source excerpt

A Cuckoo filter stores a one-to-two byte fingerprint in a hash table and finds it by checking exactly two buckets, the primary index and its XOR-derived alternate, instead of k random bit positions scattered across a large array. That spatial locality is the whole win on real CPUs. The trade-off is a hard edge: when the kick-out chain exceeds its limit, the insert fails outright.