PostgreSQL excels at transactional workloads and small-scale analytics, but for real-world large-scale analytical queries ClickHouse is purpose-built to be faster, more efficient, and significantly more economical.

BigData Boutique blog

PostgreSQL and ClickHouse serve different purposes: PostgreSQL excels at transactional workloads with row-oriented storage, while ClickHouse's columnar architecture dominates large-scale analytics. For datasets under 50K rows, PostgreSQL read replicas work fine, but beyond millions of rows, ClickHouse delivers 10x-1000x faster queries through columnar compression (10x-30x ratios), vectorized execution, and specialized table engines. The recommended production pattern is PostgreSQL for OLTP plus ClickHouse for analytics, connected via CDC, allowing each database to operate in its sweet spot while reducing storage costs and operational complexity.

ClickHouse vs PostgreSQL: Choosing the Right Database for Analytics

Where PostgreSQL Read Replicas Reach Their Limits