ClickHouse Newsletter

Hello, and welcome to the December 2025 ClickHouse newsletter!

This month, we have a Postgres extension for querying ClickHouse, an analysis of how the five major cloud data warehouses compare in terms of cost-performance, a review of the year in Postgres CDC, and more!

Inside this issue

• Featured community member: Zjan Carlo Turla
• Upcoming events
• Our gift to you: Free ClickHouse certification and new learning paths
• 25.11 release
• Introducing pg_clickhouse: A Postgres extension for querying ClickHouse
• Dlt+ClickHouse+Rill: Multi-Cloud Cost Analytics, Cloud-Ready
• Postgres CDC in ClickHouse, A year in review
• ClickHouse as a security engine: Tempesta FW's approach to L7 DDoS and bot mitigation
• How the five major cloud data warehouses compare on cost-performance
• clickhouse.build: An agentic CLI to accelerate Postgres apps with ClickHouse
• Quick reads

Featured community member

This month's featured community member is Zjan Carlo Turla, Software Engineer at Canva.

Zjan works on Canva's Observability team, where he builds and maintains systems that monitor and ensure reliability across Canva's distributed infrastructure. Previously, he worked as a DevOps Consultant supporting large-scale platforms and spent several years at Kalibrr as an SRE, migrating monolithic applications to microservices on Kubernetes.

At the recent Open House roadshow in Sydney, he shared how Canva migrated production observability workloads in ClickHouse, processing 3 million spans and 3 million logs per second for 240 million monthly active users, achieving 10x faster search and 70% cost savings.

➡️ Connect with Zjan

Upcoming events

Virtual training

Real-time Analytics

• Real-time Analytics with ClickHouse: Level 1 - January 14
• Real-time Analytics with ClickHouse: Level 2 - January 21
• Real-time Analytics with ClickHouse: Level 3 - January 28

Observability

• Observability with ClickStack: Level 2 - December 17
• Observability with ClickStack: Level 1 - February 4

Events in AMER

• Iceberg Meetup in Menlo Park - January 21st
• Iceberg Meetup in NYC - January 23rd
• New York Meetup - January 26th

Events in EMEA

• ClickHouse Meetup in Tel Aviv - December 29
• Data & AI Paris Meetup - January 22nd
• Apache Iceberg™ Meetup Belgium: FOSDEM Edition - January 30th

Events in APAC

• Under-the-Hood: Incremental Materialized Views & Dictionaries Webinar - January 15

Our gift to you: Free ClickHouse certification and new learning paths

We've launched all-new self-paced learning paths designed to deliver the hands-on experience needed to build real-world skills and expertise to match your goals. Explore our new paths today:

• Real-time Analytics with ClickHouse - Learn how to power real-time dashboards, alerts, and event-driven apps with ClickHouse.
• Observability with ClickStack - Ingest logs, metrics, and traces to monitor systems and power observability dashboards.
• Machine Learning and GenAI with ClickHouse - Use ClickHouse to prepare data, feed models, and support GenAI workflows at scale.
• Data Warehousing with ClickHouse - Coming Soon! Design, build, and optimize modern data warehouses using ClickHouse.

As our holiday gift, get certified for free through the end of 2025. Use code 2025CERTFREE at checkout to claim your certification at no cost.

➡️ Start learning

25.11 release

My favourite feature in our penultimate release of the year, 25.11, is projections as secondary indices, which lets you create lightweight projections that behave like a secondary index without duplicating complete rows of data.

This release also features faster GROUP BY operations on 8-bit and 16-bit integer keys, as well as the argAndMin and argAndMax functions, fractional LIMIT and OFFSET, and more.

➡️ Read the release post

Introducing pg_clickhouse: A Postgres extension for querying ClickHouse

David Wheeler announced the release of pg_clickhouse, a PostgreSQL extension that brings ClickHouse's analytical power directly into your Postgres queries through foreign data wrappers.

Query ClickHouse tables from Postgres with intelligent pushdown optimization that executes aggregations and filters in ClickHouse for maximum performance, giving you access to massive analytical datasets without leaving your Postgres environment.

➡️ Read the announcement

Dlt+ClickHouse+Rill: Multi-Cloud Cost Analytics, Cloud-Ready

Simon Späti demonstrates how to build a real-time FinOps dashboard using dlt to ingest AWS cost and usage reports into ClickHouse, and then visualizes the data with Rill.

The setup provides a practical blueprint for instant cost analysis at scale, with ClickHouse serving as the analytical engine to handle millions of cost records.

➡️ Read the blog post

Postgres CDC in ClickHouse, A year in review

Sai Srirampur reflects on a year of building Postgres CDC in ClickHouse Cloud, growing from a handful of PeerDB users to over 400 companies replicating more than 200 TB of data monthly.

The post highlights technical wins, such as eliminating expensive replication reconnects that caused hours of lag and reducing partition generation from over 7 hours to under a second, while outlining next steps to close data modeling gaps and further scale logical replication.

➡️ Read the blog post

ClickHouse as a security engine: Tempesta FW's approach to L7 DDoS and bot mitigation

Tempesta Technologies developed WebShield, an open-source bot detection system that utilizes ClickHouse to analyze access logs in real-time and automatically block Layer 7 DDoS attacks and malicious bots.

➡️ Read the blog post