ByteDance Data Platform

Jan 24, 2022 · Databases

Accelerating ClickHouse LowCardinality: Merge Optimizations & Auto Fallback

This article details how ByteDance’s ClickHouse UBA edition improves dictionary encoding for low‑cardinality columns by redesigning the Part‑merge process, introducing a single‑dictionary merge, and implementing an automatic fallback for high‑cardinality columns, resulting in significant storage savings and query‑performance gains across large‑scale applications.