# September 2026 newsletter

> Source: <https://clickhouse.com/blog/202609-newsletter>
> Published: 2026-09-17 13:42:49+00:00

Hello and welcome to another ClickHouse newsletter!

We’ve got another feature-packed ClickHouse release, with custom HTTP handlers, pipelined SQL, and Japanese/Chinese tokenizers for the text-index.

Elsewhere, Mohamed Hussain S dives into the replication queue, Tom Schreiber and Lionel Palacin share the first end-to-end results from CostBench, and Himanshu Pandey walks us through reading ClickHouse query plans.

We also have preview releases of PromQL, On-Demand Compute, AI functions, and sub-second Postgres replication to ClickHouse

## Featured community member: Rory Shanks

This month's featured community member is Rory Shanks, ClickHouse Engineer at PostHog.

Rory’s background is in site reliability and cloud platform engineering, and he previously worked as a Staff DevOps Engineer at ENWAY and a Senior Site Reliability Engineer at Inkitt and powercloud.

Rory contributed several improvements to ClickHouse 26.8, released at the end of August.

First, he added an [option for replicas to fetch already mutated data parts](https://github.com/ClickHouse/ClickHouse/pull/113020) from another replica, avoiding the need to repeat mutation work locally. Additionally, he added [caching for tokens absent from the text index](https://github.com/ClickHouse/ClickHouse/pull/112742) and [improved JSON subcolumn reads](https://github.com/ClickHouse/ClickHouse/pull/113008) by reusing column metadata during conversions.

➡️ [Connect with Rory on LinkedIn](https://www.linkedin.com/in/rorylshanks/)

## Open House Roadshow

We’re halfway through the [Open House Roadshow](https://clickhouse.com/company/events?category=Open+House&utm_source=clickhouse&utm_medium=email&utm_campaign=202609-newsletter&ref=newsletter), but there are still visits to come in [Bangalore](https://clickhouse.com/company/events/202609-APJ-India-Bangalore-Open-House-Roadshow?utm_source=clickhouse&utm_medium=email&utm_campaign=202609-newsletter&ref=newsletter) (Sep 22), [London](https://clickhouse.com/openhouse/london-2026?utm_source=clickhouse&utm_medium=email&utm_campaign=202609-newsletter&ref=newsletter) (Sep 30), and [Munich](https://clickhouse.com/company/events/202610-munich-open-house?utm_source=clickhouse&utm_medium=email&utm_campaign=202609-newsletter&ref=newsletter) (Oct 6), so don’t forget to sign up!

➡️ [See all Open House locations](https://clickhouse.com/company/events?category=Open+House&utm_source=clickhouse&utm_medium=email&utm_campaign=202609-newsletter&ref=newsletter)

## 26.8 release

After last month’s mega 26.7 release blog post, we’ve decided to try something different this month: multiple smaller posts!

The 26.8 release includes a series of features, such as custom HTTP handlers and dynamic query filtering, that enable you to use [ClickHouse as a streaming HTTP API](https://clickhouse.com/blog/clickhouse-streaming-http-api?utm_source=clickhouse&utm_medium=email&utm_campaign=202609-newsletter&ref=newsletter). This release also adds a new `|>` operator that lets us write [queries as a sequence of transformations](https://clickhouse.com/blog/pipelined-sql-26.8?utm_source=clickhouse&utm_medium=email&utm_campaign=202609-newsletter&ref=newsletter).

The release also adds a `system.user_query_log` table that shows only the current user’s queries, a URL database engine, and Japanese and Chinese tokenizer support for the text index.

## Understanding the replication queue in ClickHouse

Mohamed Hussain S explores ClickHouse’s replication queue by stopping a replica and investigating the backlog.

He shows how to use the `system.replicas` and `system.replication_queue` system tables to diagnose issues, and explains why a non-empty queue doesn’t necessarily mean something is wrong.

## Measuring real-time performance per dollar under continuous load: CostBench’s first end-to-end results

Tom Schreiber and Lionel Palacin share the first end-to-end results from [CostBench](https://clickhouse.com/blog/costbench-data-warehouse-cost-performance?utm_source=clickhouse&utm_medium=email&utm_campaign=202609-newsletter&ref=newsletter), an open benchmark for cloud data warehouse cost-performance: performance-per-dollar, rather than just speed.

They test ClickHouse Cloud, Snowflake, BigQuery, and Redshift Serverless under continuous ingestion, measuring the cost of keeping fresh data ready for queries alongside query performance.

In a follow-up post, they [take a closer look at the ClickHouse Cloud and Snowflake results](https://clickhouse.com/blog/clickhouse-vs-snowflake-real-time-performance-per-dollar?utm_source=clickhouse&utm_medium=email&utm_campaign=202609-newsletter&ref=newsletter), explaining how their architectures and billing models contribute to the performance-per-dollar gap.

## Announcing On-Demand Compute: Instant compute for your most intensive workloads

This is one of the biggest features we have been working on: On-Demand Compute is now in [private preview](https://clickhouse.com/cloud/on-demand-compute-waitlist?utm_source=clickhouse&utm_medium=email&utm_campaign=202609-newsletter&ref=newsletter).

You are now a step away from offloading intensive workloads to dedicated ClickHouse workers. And it doesn’t land alone! It comes with two friends:

• A new cost-based optimizer (CBO)

• A new distributed query execution framework

The dream for anybody wanting to offload ad-hoc or data lake queries to dedicated workers!

Curious to learn more? Melvyn Peignon will present a [live webinar on September 24th](https://clickhouse.com/company/events/202609-AMER-Webinar-On-Demand-Compute?utm_source=clickhouse&utm_medium=email&utm_campaign=202609-newsletter&ref=newsletter), where he’ll explain how it works, give a live demo, and talk through the six-month roadmap.

## ClickHouse 26.8 LTS: 57 Breaking Changes Since 26.3

Mohamed Hussain S has written an alternative blog post for the 26.8 release, exploring changes since the previous LTS release, 26.3.

He highlights breaking changes and new defaults across all five releases, with a checklist of what to audit before upgrading and monitor afterward.

## Postgres Round-up

We’ve been publishing more and more [Postgres content](https://clickhouse.com/blog?search=postgres&utm_source=clickhouse&utm_medium=email&utm_campaign=202609-newsletter&ref=newsletter) as the weeks go by, so I thought it deserved its own section in the newsletter.

- Sai Srirampur announced [WalShadow](https://clickhouse.com/blog/introducing-walshadow?utm_source=clickhouse&utm_medium=email&utm_campaign=202609-newsletter&ref=newsletter) , an open-source engine that replicates Postgres data to ClickHouse directly from the physical WAL. It’s available as an open-source project or in[private preview on ClickHouse Managed Postgres](https://clickhouse.com/cloud/postgres/walshadow?utm_source=clickhouse&utm_medium=email&utm_campaign=202609-newsletter&ref=newsletter) .
- Kunal Gupta announced the availability of [ClickHouse Managed Postgres on Google Cloud](https://clickhouse.com/blog/postgres-managed-by-clickhouse-gcp-private-preview?utm_source=clickhouse&utm_medium=email&utm_campaign=202609-newsletter&ref=newsletter) , also in[private preview](https://clickhouse.com/cloud/postgres?utm_source=clickhouse&utm_medium=email&utm_campaign=202609-newsletter&ref=newsletter#gcp-waitlist) for the time being.
- David Wheeler announced the open-source [chdb Postgres extension](https://clickhouse.com/blog/introducing-chdb-postgres?utm_source=clickhouse&utm_medium=email&utm_campaign=202609-newsletter&ref=newsletter) , which expands Postgres import and export features via the[chDB](https://clickhouse.com/docs/chdb?utm_source=clickhouse&utm_medium=email&utm_campaign=202609-newsletter&ref=newsletter) library.
- Gülçin Yıldırım Jelínek has started writing a series of blog posts on Postgres 19. So far, she’s covered [monitoring](https://clickhouse.com/blog/postgres-19-monitoring-whats-new?utm_source=clickhouse&utm_medium=email&utm_campaign=202609-newsletter&ref=newsletter) ,[new system views](https://clickhouse.com/blog/postgres-19-new-system-views?utm_source=clickhouse&utm_medium=email&utm_campaign=202609-newsletter&ref=newsletter) , and[read-your-writes](https://clickhouse.com/blog/postgresql-19-wait-for-read-your-writes?utm_source=clickhouse&utm_medium=email&utm_campaign=202609-newsletter&ref=newsletter) .
- Kaushik Iska explains how ClickHouse Managed Postgres [protects Postgres from resource-hungry supporting processes](https://clickhouse.com/blog/protect-postgres-from-supporting-processes?utm_source=clickhouse&utm_medium=email&utm_campaign=202609-newsletter&ref=newsletter) .
- Sai Srirampur explores [how storage choices affect Postgres performance](https://clickhouse.com/blog/posette-talk-recap-postgres-isnt-slow-your-storage-is?utm_source=clickhouse&utm_medium=email&utm_campaign=202609-newsletter&ref=newsletter) .
- Cristina Albu and Yashpreet Bathla walk through [a new onboarding flow for ClickHouse Managed Postgres](https://clickhouse.com/blog/clickhouse-managed-postgres-onboarding?utm_source=clickhouse&utm_medium=email&utm_campaign=202609-newsletter&ref=newsletter) .

## Introducing ClickHouse's new TimeSeries Engine: Your drop-In Prometheus replacement

James Cunningham introduces PromQL and the TimeSeries table engine in ClickHouse Cloud, now in [private preview](https://clickhouse.com/cloud/promql-support-waitlist?utm_source=clickhouse&utm_medium=email&utm_campaign=202609-newsletter&ref=newsletter).

You can send metrics to ClickHouse through Prometheus remote write and query them with PromQL in Grafana, ClickHouse, or ClickStack, all while keeping your existing collection setup.

## Quick reads

- Saarth Soni [compares streaming and batch counts of Wikipedia edits](https://medium.com/@saarthsoni/wikipulse-what-streaming-and-batch-actually-disagree-about-afbd88e1c267) using Quix Streams and ClickHouse, exploring why the same data can yield different results.
- Oleksandr Andrushchenko [compares ClickHouse and PostgreSQL for SMS analytics](https://medium.com/@oleksandr.andrushchenko1988/clickhouse-vs-postgresql-what-happens-at-billion-row-scale-8506a11f2836) , reporting that ClickHouse processes 10 times more rows and exploring how query shape affects performance.
- Himanshu Pandey [explains how to read ClickHouse query plans](https://medium.com/@hp12/reading-a-clickhouse-explain-plan-ffb4e8353098) to understand query execution and investigate performance.
- Andriy Yakovlev and George Larionov [introduce AI Functions in ClickHouse](https://clickhouse.com/blog/ai-functions-in-clickhouse?utm_source=clickhouse&utm_medium=email&utm_campaign=202609-newsletter&ref=newsletter) , bringing AI models into SQL for tasks such as text generation, classification, and embeddings.
- Pete Hampton [shows how to build semantic search with Google’s MCP Toolbox and ClickHouse](https://clickhouse.com/blog/mcp-toolbox-clickhouse-vectors?utm_source=clickhouse&utm_medium=email&utm_campaign=202609-newsletter&ref=newsletter) , automatically turning text into embeddings for storage and search.
- Lareb Zafar [introduces ClickGap](https://clickhouse.com/blog/clickgap-autonomous-qa-for-clickhouse?utm_source=clickhouse&utm_medium=email&utm_campaign=202609-newsletter&ref=newsletter) , an autonomous QA agent that tests merged ClickHouse changes and traces regressions to the commits that introduced them.

## Upcoming events

### Global virtual events

- Webinar: [What if your most intensive queries could run on more compute? Introducing On-Demand Compute](https://clickhouse.com/company/events/202609-AMER-Webinar-On-Demand-Compute?utm_source=clickhouse&utm_medium=email&utm_campaign=202609-newsletter&ref=newsletter) - Sep 24, 2026 (AMER)
- Webinar: [What if your most intensive queries could run on more compute? Introducing On-Demand Compute](https://clickhouse.com/company/events/202610-EMEA-Webinar-On-Demand-Compute?utm_source=clickhouse&utm_medium=email&utm_campaign=202609-newsletter&ref=newsletter) - Oct 7, 2026 (EMEA)

### Virtual training

- [Query Optimization with ClickHouse Workshop](https://clickhouse.com/company/events/202609-APJ-query-optimization-workshop?utm_source=clickhouse&utm_medium=email&utm_campaign=202609-newsletter&ref=newsletter) - Sep 29, 2026
- [PostgreSQL and ClickHouse, Better Together](https://clickhouse.com/company/events/202609-AMER-PostgreSQL-ClickHouse-Better-Together?utm_source=clickhouse&utm_medium=email&utm_campaign=202609-newsletter&ref=newsletter) -  - Oct 8, 2026
- [Real-time Analytics with ClickHouse: Level 1](https://clickhouse.com/company/events/202610-APJ-Real-time-Analytics-ClickHouse-Level1?utm_source=clickhouse&utm_medium=email&utm_campaign=202609-newsletter&ref=newsletter) - Oct 20, 2026
- [Real-time Analytics with ClickHouse: Level 2](https://clickhouse.com/company/events/202610-APJ-Real-time-Analytics-ClickHouse-Level2?utm_source=clickhouse&utm_medium=email&utm_campaign=202609-newsletter&ref=newsletter) - Oct 21, 2026
- [Real-time Analytics with ClickHouse: Level 3](https://clickhouse.com/company/events/202610-APJ-Real-time-Analytics-ClickHouse-Level3?utm_source=clickhouse&utm_medium=email&utm_campaign=202609-newsletter&ref=newsletter) - Oct 22, 2026

### Events in AMER

- [Rows and Columns summit San Francisco](https://luma.com/clickh-wavw) - Sep 22nd
- [Google Cloud Summit Brasil](https://cloudonair.withgoogle.com/events/google-cloud-summit-brasil-2026-1) - Sep 23-24, 2026
- [Runway by RunReveal](https://runway.runreveal.com/) - San Francisco - Sep 29, 2026
- [CoreWeave Fully Connected](https://coreweave.com/fully-connected-2026) - San Francisco - Sep 29 - Oct 2, 2026
- [Sao Paulo In-person training](https://clickhouse.com/company/events/202610-LATAM-SaoPaulo-Observability-with-ClickStack/?utm_source=clickhouse&utm_medium=email&utm_campaign=202609-newsletter&ref=newsletter) - Observabilidade com ClickStack - Sao Paulo - Oct 8, 2026
- Sao Paulo Meetup - Observabilidade de Agentes em Escala: o Case do iFood com Langfuse - Sao Paulo - Oct 8, 2026

### Events in EMEA

- [AI Engineer Paris (Langfuse) - Sept 22-24, 2026](https://ai.engineer/paris/2026)
- [Stockholm In-Person Training: Real-time Analytics with ClickHouse](https://clickhouse.com/company/events/202609-EMEA-Stockholm-Real-time-Analytics-w-ClickHouse?utm_source=clickhouse&utm_medium=email&utm_campaign=202609-newsletter&ref=newsletter) - Sep 23, 2026
- [AI Builders and Databases Barcelona](https://luma.com/p7td11mb) - Sep 23, 2026
- [BigDataLondon - Sept 23-24, 2026](https://www.bigdataldn.com/)
- [Copenhagen In-person training - Sept 24, 2026](https://clickhouse.com/company/events/202609-EMEA-Copenhagen-Real-time-Analytics-w-ClickHouse?utm_source=clickhouse&utm_medium=email&utm_campaign=202609-newsletter&ref=newsletter)
- [FabCON - Sept 28 - Oct 1](https://espc.tech/conference/fabcon-europe-2026/)
- [FabCon Lunch and Learn - Sept 30, 2026](https://go2.striim.com/2026-fabcon-ai-roundtable?tracker=clickhouse)
- [AI Builders and Databases Paris](https://clickhouse.com/company/events/ai-builders-and-databases-sep-paris-2026?utm_source=clickhouse&utm_medium=email&utm_campaign=202609-newsletter&ref=newsletter) - Sep 29, 2026
- [Agentic AI Forum Dubai](https://www.agenticaiforum.net/) - Sept 30, 2026
- [London In-person training - From 0 to Production: Observing and Improving AI Agents with Langfuse](https://clickhouse.com/company/events/202609-EMEA-London-AI-Agents-w-Langfuse?utm_source=clickhouse&utm_medium=email&utm_campaign=202609-newsletter&ref=newsletter) - Sep 30, 2026
- [London In-person training - One Database, Every Workload: A ClickHouse Workshop](https://clickhouse.com/company/events/202609-EMEA-London-One-Database-Every-Workload?utm_source=clickhouse&utm_medium=email&utm_campaign=202609-newsletter&ref=newsletter) - Sep 30, 2026
- [Open House Roadshow London](https://clickhouse.com/openhouse/london-2026?utm_source=clickhouse&utm_medium=email&utm_campaign=202609-newsletter&ref=newsletter) - Sep 30, 2026
- [Munich In-person training - From 0 to Production: Observing and Improving AI Agents with Langfuse](https://clickhouse.com/company/events/202610-EMEA-Munich-AI-Agents-w-Langfuse?utm_source=clickhouse&utm_medium=email&utm_campaign=202609-newsletter&ref=newsletter) - Oct 6, 2026
- [Munich In-person training - One Database, Every Workload: A ClickHouse Workshop](https://clickhouse.com/company/events/202610-EMEA-Munich-One-Database-Every-Workload?utm_source=clickhouse&utm_medium=email&utm_campaign=202609-newsletter&ref=newsletter) - Oct 6, 2026
- [Open House Roadshow Munich](https://clickhouse.com/company/events/202610-munich-open-house?utm_source=clickhouse&utm_medium=email&utm_campaign=202609-newsletter&ref=newsletter) - Oct 6, 2026
- [World Summit AI Amsterdam](https://worldsummit.ai/) - Oct 7-8, 2026
- [AI Builders and Databases Stockholm](https://clickhouse.com/company/events/ai-builders-and-databases-oct-stockholm-2026?utm_source=clickhouse&utm_medium=email&utm_campaign=202609-newsletter&ref=newsletter) - Oct 8, 2026
- [AI Builders and Databases Tel Aviv](https://clickhouse.com/company/events/ai-builders-and-databases-oct-tel-aviv-2026?utm_source=clickhouse&utm_medium=email&utm_campaign=202609-newsletter&ref=newsletter) - Oct 12, 2026
- [SRECon Dublin Happy Hour by the Quay](https://luma.com/clickh-6n6u) - Oct 13, 2026
- [SRECon Dublin](https://www.usenix.org/conference/srecon25emea) - Oct 13-15, 2026
- [Data Innovation Summit Dubai](https://datainnovationsummit.com/region/mea/) Oct 14-15
- [Oslo In-Person Training: Real-time Analytics with ClickHouse](https://clickhouse.com/company/events/202610-EMEA-Oslo-Real-time-Analytics-w-ClickHouse?utm_source=clickhouse&utm_medium=email&utm_campaign=202609-newsletter&ref=newsletter) - Oct 14, 2026
- [PostgreSQL Conference Europe - Oct 20-23, 2026](https://www.postgresql.org/about/event/pgconfeu-2026-2587/)
- [AWS Cloud Days Riyadh](https://aws.amazon.com/events/cloud-days/riyadh/) - Oct 21, 2026
- [London In-Person Training: Real-time Analytics with ClickHouse](https://clickhouse.com/company/events/202610-EMEA-London-Real-time-Analytics-w-ClickHouse?utm_source=clickhouse&utm_medium=email&utm_campaign=202609-newsletter&ref=newsletter) - Oct 21, 2026
- [AI Builders and Analytics London](https://clickhouse.com/company/events/ai-builders-and-analytics-oct-london-2026?utm_source=clickhouse&utm_medium=email&utm_campaign=202609-newsletter&ref=newsletter) - Oct 21, 2026
- [AI Builders and Databases Dubai](https://luma.com/clickh-vtzf) - Oct 22, 2026
- [Battle of the Quants London - Oct 22, 2026](https://battleofthequants.com/london-2026/)
- [Dublin In-Person Training: Real-time Analytics with ClickHouse](https://clickhouse.com/company/events/202610-EMEA-Dublin-Real-time-Analytics-w-ClickHouse?utm_source=clickhouse&utm_medium=email&utm_campaign=202609-newsletter&ref=newsletter) - Oct 23, 2026
- [AI Builders and Databases Madrid](https://luma.com/clickh-1qqg) - Nov 3, 2026
- [AI Builders and Databases Cyprus](https://clickhouse.com/company/events/ai-builders-and-databases-nov-cyprus-2026?utm_source=clickhouse&utm_medium=email&utm_campaign=202609-newsletter&ref=newsletter) - Limassol - Nov 26, 2026

### Events in APAC

- [Open House Roadshow Bangalore](https://clickhouse.com/company/events/202609-APJ-India-Bangalore-Open-House-Roadshow?utm_source=clickhouse&utm_medium=email&utm_campaign=202609-newsletter&ref=newsletter) - Sep 22, 2026
- Singapore - [From 0 to Production: Observing and Improving AI Agents with Langfuse](https://clickhouse.com/company/events/202609-APJ-Singapore-AI-Agents-w-Langfuse?utm_source=clickhouse&utm_medium=email&utm_campaign=202609-newsletter&ref=newsletter) - Sep 24, 2026
- Singapore: [One Database, Every Workload: A ClickHouse Workshop](https://clickhouse.com/company/events/202609-APJ-Singapore-One-Database-Every-Workload?utm_source=clickhouse&utm_medium=email&utm_campaign=202609-newsletter&ref=newsletter) - Sep 24, 2026
- Singapore: [Build Better LLM Apps](https://clickhouse.com/company/events/build-better-llm-apps-with-langfuse-singapore?utm_source=clickhouse&utm_medium=email&utm_campaign=202609-newsletter&ref=newsletter) - Sep 29, 2026
- Auckland: [One Database, Every Workload: A ClickHouse Workshop](https://clickhouse.com/company/events/one-database-every-workload-new-zealand?utm_source=clickhouse&utm_medium=email&utm_campaign=202609-newsletter&ref=newsletter) - Oct 6, 2026
- Auckland: [Build a unified data stack with Postgres and ClickHouse](https://clickhouse.com/company/events/nz-unified-data-stack-postgres-clickhouse?utm_source=clickhouse&utm_medium=email&utm_campaign=202609-newsletter&ref=newsletter) - Oct 6, 2026
- Singapore: [Confluent Financial Services Leaders Summit](https://events.confluent.io/confluent-fsi-singapore-2026) - Oct 9, 2026
- Sydney: [Build a unified data stack for real-time AI with Postgres and ClickHouse](https://clickhouse-workshop-syd.innovatusmediaevents.com/) - Oct 13, 2026
- Melbourne: [Build Better LLM Apps](https://clickhouse.com/company/events/build-better-llm-apps-with-langfuse-melbourne?utm_source=clickhouse&utm_medium=email&utm_campaign=202609-newsletter&ref=newsletter) - Oct 15, 2026