Tag
cardinality-estimation
- Jul 21, 2026 Counting Distinct Elements with HyperLogLog Registers How a fixed array of small registers estimates cardinality to within about one percent, why the estimator uses a harmonic mean, and how register-wise maximum makes sketches mergeable. algorithms
- Feb 24, 2025 HyperLogLog: Estimating Cardinality from a Register Array How stochastic averaging over harmonic means turns a fixed array of small registers into a cardinality estimate with roughly 1.04/sqrt(m) relative error. data structures
- Sep 6, 2023 Counting Distinct Values Without Storing Every Record How log-frequency analysis uses register-based sketches, what the relative error formula implies for sizing, and when an exact set is the cheaper answer. observability