ClickHouse CDC Patterns

Overview

Change Data Capture (CDC) replicates database changes to ClickHouse for analytics. Core principle: Capture changes at source, transform for column-storage, handle deletes gracefully.

Key challenge: ClickHouse isn't designed for updates/deletes. Use ReplacingMergeTree or append-only patterns.

When to Use

Symptoms:

• Need to sync PostgreSQL/MySQL tables to ClickHouse
• Want real-time analytics on transactional data
• Schema changes breaking replication pipeline
• Unsure how to handle DELETE operations

When NOT to use: