UltraLogLog

Rust implementation of the UltraLogLog algorithm. Ultraloglog is more space efficient than the widely used HyperLogLog, but can be slower. FGRA estimator or MLE estimator can be used.

Usage

use ultraloglog::{Estimator, MaximumLikelihoodEstimator, OptimalFGRAEstimator, UltraLogLog};

let mut ull = UltraLogLog::new(6).unwrap();

ull.add_value("apple")
    .add_value("banana")
    .add_value("cherry")
    .add_value("033");
let est = ull.get_distinct_count_estimate();

The serde feature can be activated so that the sketch can be saved to disk and then loaded.

use ultraloglog::{Estimator, MaximumLikelihoodEstimator, OptimalFGRAEstimator, UltraLogLog};
use std::fs::{remove_file, File};
use std::io::{BufReader, BufWriter};

let file_path = "test_ultraloglog.bin";

// Create UltraLogLog and add data
let mut ull = UltraLogLog::new(5).expect("Failed to create ULL");
ull.add(123456789);
ull.add(987654321);
let original_estimate = ull.get_distinct_count_estimate();

// Save to file using writer
let file = File::create(file_path).expect("Failed to create file");
let writer = BufWriter::new(file);
ull.save(writer).expect("Failed to save UltraLogLog");

// Load from file using reader
let file = File::open(file_path).expect("Failed to open file");
let reader = BufReader::new(file);
let loaded_ull = UltraLogLog::load(reader).expect("Failed to load UltraLogLog");
let loaded_estimate = loaded_ull.get_distinct_count_estimate();

Reference

Ertl, O., 2024. UltraLogLog: A Practical and More Space-Efficient Alternative to HyperLogLog for Approximate Distinct Counting. Proceedings of the VLDB Endowment, 17(7), pp.1655-1668.