HyperLogLog in Presto: A significantly faster way to handle cardinality estimation

What this post added

This post details the implementation of the HyperLogLog (HLL) algorithm in Presto to significantly improve the performance of cardinality estimation for large datasets. It explains the evolution of cardinality estimation algorithms from simple minimum value estimation to probabilistic counting and LogLog, culminating in HLL. The post highlights the memory efficiency and speed improvements (7x to 1,000x) achieved by using HLL in Presto for tasks like analyzing A/B tests.