Jordi Villar shares four months of incremental ClickHouse optimizations that reduced a critical query from 85+ seconds to sub-second latency. The main bottleneck was using ReplacingMergeTree with heavy FINAL clause usage on mutable Kafka-sourced events. No single clever trick drove the improvement — instead, basic optimizations compounded over time.
Background
ClickHouse is an open-source column-oriented database management system for real-time analytics, widely used for high-volume event processing. ReplacingMergeTree is a ClickHouse table engine variant that handles mutable data by replacing duplicate rows based on a version column.
- Source
- Lobsters
- Published
- Sep 10, 2026 at 12:06 AM
- Score
- 7.0 / 10