When ClickHouse CPU Explodes: A Practical Lesson in OLAP vs OLTP Design
Abstract
ClickHouse is an extremely fast analytical database—but it is not a key-value store.
This article walks through a real-world performance incident where a seemingly harmless query (LIMIT 1) caused massive CPU usage, explains why it happened, and presents a systemic fix using proper data-responsibility separation between OLAP and OLTP systems.
If you are using ClickHouse for event tracking, affiliate analytics, or high-volume logging, this will save you from a painful production outage.