---
title: "Clickhouse"
description: "High-performance open-source columnar database management system designed for real-time analytics and data warehousing at scale"
---

# Clickhouse
> High-performance open-source columnar database management system designed for real-time analytics and data warehousing at scale

## Articles

### [Introducing ClickStack Cloud: Serverless observability powered by ClickHouse](https://yomu.fyi/post/introducing-clickstack-cloud-serverless-observability-powered-by-click.md)
- Company: [Clickhouse](https://yomu.fyi/company/clickhouse.md)
- Published: May 27, 2026
- Type: Announcement

ClickStack Cloud is entering private preview as a fully managed, serverless observability service built on ClickHouse for teams that want ClickHouse-powered logs, metrics, and traces without operating the underlying infrastructure. Users send OpenTelemetry data to a managed OTLP endpoint, while the service handles ingestion, durable buffering through an object-storage-backed event queue, scaling, storage, and query serving, then exposes telemetry in the ClickStack UI with integrated authentication and RBAC. The preview separates ingestion and query resources and is developing automatic tuning based on query patterns, including materialized fields, primary-key adjustments, materialized views, and indexes. Dedicated query compute for agentic and high-volume analytical workloads is planned after the preview, while pricing remains unfinished and the existing Managed ClickStack offering remains intended for teams requiring direct infrastructure and schema control.


### [Introducing CostBench: an open benchmark for data warehouse cost-performance](https://yomu.fyi/post/introducing-costbench-an-open-benchmark-for-data-warehouse-cost-perfor.md)
- Company: [Clickhouse](https://yomu.fyi/company/clickhouse.md)
- Author: Tom Schreiber, Lionel Palacin
- Published: May 27, 2026
- Type: Benchmark

Traditional data warehouse benchmarks measure query execution speed without accounting for the varying compute costs across platforms. CostBench introduces an open benchmarking framework designed to evaluate data warehouses on a performance-per-dollar metric across both read and write workloads. Its initial release evaluates ClickHouse Cloud, Snowflake, Databricks, BigQuery, and Redshift using 43 production-derived analytical queries on an anonymized dataset combined with each vendor's compute billing model. In these read-side tests, ClickHouse Cloud maintained high speed at lower costs as data scaled, outperforming the nearest competitor by 23 times in cost-performance. The benchmark repository openly publishes its scripts, configurations, pricing assumptions, and raw JSON results to ensure all comparative metrics remain fully inspectable and reproducible.


### [Postgres managed by ClickHouse is now in beta](https://yomu.fyi/post/postgres-managed-by-clickhouse-is-now-in-beta.md)
- Company: [Clickhouse](https://yomu.fyi/company/clickhouse.md)
- Author: Sai Srirampur
- Published: May 27, 2026
- Type: Announcement

ClickHouse Cloud has launched a fully managed Postgres service in beta to combine transactional and analytical workloads within a single platform. Backed by local NVMe storage, the service provides up to ten times faster transactional performance alongside native change data capture into ClickHouse. Developers can query across both transactional and analytical layers using the pg\_clickhouse extension without managing custom data pipelines. The platform also offers managed migration workflows via ClickPipes, database branching, point-in-time recovery, high availability with up to two standbys, and support for over ninety PostgreSQL extensions. More than fifty virtual machine configurations are available, ranging from single vCPU instances to clusters with ninety-six vCPUs and sixty terabytes of NVMe storage.


### [Introducing multi-stage distributed query execution in ClickHouse Cloud](https://yomu.fyi/post/introducing-multi-stage-distributed-query-execution-in-clickhouse-clou.md)
- Company: [Clickhouse](https://yomu.fyi/company/clickhouse.md)
- Author: Alexander Gololobov
- Published: May 27, 2026
- Type: Announcement

ClickHouse Cloud introduced multi-stage distributed query execution to improve scaling for large joins and high-cardinality aggregations across multi-node clusters. Prior execution models relied on physical sharding or parallel replicas, which lacked the ability to freely repartition intermediate data between query stages. By splitting query plans into stages connected by exchange operators, worker nodes can shuffle, broadcast, scatter, or gather intermediate data during execution. In TPC-H benchmarks at scale factor 100 on eight nodes, total query time dropped from 117.6 seconds to 54.7 seconds, with scan-dominated queries showing near-linear 7.4x speedups. While currently in private preview with a rule-based planner, future work includes developing a cost-based optimizer to select optimal aggregation and join strategies automatically.


### [Native random sampling in ClickHouse](https://yomu.fyi/post/native-random-sampling-in-clickhouse.md)
- Company: [Clickhouse](https://yomu.fyi/company/clickhouse.md)
- Author: Mark Needham
- Published: May 22, 2026
- Type: Tutorial

ClickHouse native random sampling enables aggregate queries to execute against a representative fraction of data when querying full datasets is too slow. To maintain sampling accuracy, tables require a sample key derived from high-cardinality columns using hash functions like sipHash64 to ensure an even distribution. The sample key must be included in the primary key ORDER BY expression, preferably at the front to let ClickHouse quickly skip index granules. Queries can sample data deterministically by specifying a fractional ratio or a minimum row threshold, scaling aggregate counts using the virtual column \_sample\_factor. In benchmark tests on a 30-million-row dataset, sampling 10% of records reduced query latency by approximately 80% while retaining approximate metrics suitable for exploratory analysis.


### [Integrating the Rust Delta Kernel into ClickHouse](https://yomu.fyi/post/integrating-the-rust-delta-kernel-into-clickhouse.md)
- Company: [Clickhouse](https://yomu.fyi/company/clickhouse.md)
- Author: Melvyn Peignon, Kseniia Sumarokova, Raúl Marín
- Published: May 22, 2026
- Type: Problem & solution

ClickHouse initially built native protocol support to read Delta Lake tables, but maintaining pace with the format's evolving specification created high complexity and fragmented features. To resolve this, engineers integrated the Rust Delta Kernel to offload protocol handling while retaining ClickHouse's optimized Parquet data reading. The Delta Kernel parses JSON transaction logs, resolves snapshots, manages transactional write metadata, and exposes schema evolution mapping alongside Change Data Feed streams. ClickHouse also contributed upstream enhancements to the Rust kernel, adding dynamic runtime logging and asynchronous metadata processing via FFI handles. While ClickHouse can attach to existing Delta tables, the integration cannot yet initialize empty Delta Lake tables.


### [May 2026 newsletter](https://yomu.fyi/post/may-2026-newsletter.md)
- Company: [Clickhouse](https://yomu.fyi/company/clickhouse.md)
- Author: Mark Needham
- Published: May 21, 2026
- Type: Announcement

The May 2026 ClickHouse newsletter details enterprise observability migrations, ecosystem integrations, and core database enhancements. Digital banking platform Qonto migrated from Grafana Tempo to ClickHouse Cloud, compressing 231 TB of raw trace metadata to 376 GB while expanding query windows to two weeks and introducing an AI incident companion. Similarly, LINE MAN Wongnai consolidated multiple business clusters onto self-hosted ClickHouse, achieving 1.5 million rows per second peak ingest, 100% trace retention, and a 53% reduction in observability costs. Comparative log analytics benchmarks demonstrated that ClickHouse utilized 5x less disk space and achieved 4 to 6x faster cold query execution than Elasticsearch across 50 billion rows. Additional updates include the ClickHouse 26.4 release featuring improved SQL compatibility, new agent telemetry adapters in Mastra, and SQL-based alerting capabilities in ClickStack.


### [clickhousectl v0.2.0: Postgres, ClickPipes and more](https://yomu.fyi/post/clickhousectl-v0-2-0-postgres-clickpipes-and-more.md)
- Company: [Clickhouse](https://yomu.fyi/company/clickhouse.md)
- Author: Al Brown
- Published: May 20, 2026
- Type: Announcement

clickhousectl v0.2.0 expands the beta CLI with local and ClickHouse Cloud managed Postgres, ClickPipes, SQL over HTTP for Cloud services, agent-oriented output changes, and a standalone Rust client for the ClickHouse Cloud API. Local Postgres runs in Docker, is keyed by name and major version, stores isolated data under .clickhouse/servers/-pg/data/, and supports versions 16, 17, and 18. ClickPipes covers batch, streaming, CDC, and snapshot sources including object storage, Kafka-compatible systems, Kinesis, Postgres, MySQL, MongoDB, and BigQuery. Cloud queries use a provisioned or lazily enabled Query Endpoint and service-scoped API key, while the endpoint uses sql\_console\_admin and the key has no organization-level roles. The release also adds Markdown-style tables and credential debugging, with more than 5,000 users reported five weeks into the project.


### [What's new in ClickStack - April 2026](https://yomu.fyi/post/what-s-new-in-clickstack-april-2026.md)
- Company: [Clickhouse](https://yomu.fyi/company/clickhouse.md)
- Author: The ClickStack Team
- Published: May 19, 2026
- Type: Announcement

ClickStack's April release introduces several core enhancements across querying, alerting, and dashboard visualization capabilities. The platform added SQL-powered alerting, allowing teams to express complex statistical rules like rolling baselines and anomaly detection using native ClickHouse SQL and window functions without external pipelines. To improve search and filtering performance across common observability workloads, the default otel\_logs schema was redesigned with ClickHouse text indexes and adjusted ordering keys. Furthermore, heatmaps transitioned into a first-class chart type inside the shared visualization system for latency distribution tracking. The update also delivers persistent alert execution error reporting, expanded threshold comparison operators, and per-series number formatting across dashboards.


### [How ChatFeatured migrated from PlanetScale Postgres to Postgres Managed by ClickHouse to power AI brand discovery](https://yomu.fyi/post/how-chatfeatured-migrated-from-planetscale-postgres-to-postgres-manage.md)
- Company: [Clickhouse](https://yomu.fyi/company/clickhouse.md)
- Author: ClickHouse
- Published: May 18, 2026
- Type: Problem & solution

ChatFeatured, a Toronto-based startup, helps brands track and improve how AI models discover and recommend them, including by analyzing cited sources and guiding content production. As prompt ingestion grew to about 1,000 prompts daily across six AI models, managed Postgres instances became slow, CPU reached 90% during ingestion windows, and PlanetScale hit an IOPS limit; analytics queries remained the deeper constraint. The team migrated from PlanetScale to Postgres managed by ClickHouse using the Postgres-to-Postgres ClickPipes connector, which handled initial load, schema transfer, continuous sync, and a five-minute maintenance window; the migration took 30 minutes overall. This setup retains Postgres for transactional workloads while providing a built-in path to ClickHouse for analytics, and a 30-day LifestyleRx query fell from about two and a half minutes to less than a second, with 20x compression reported for CDN log data.


### [How the D. E. Shaw group powers high-cardinality observability at scale with ClickHouse](https://yomu.fyi/post/how-the-d-e-shaw-group-powers-high-cardinality-observability-at-scale.md)
- Company: [Clickhouse](https://yomu.fyi/company/clickhouse.md)
- Author: ClickHouse
- Published: May 15, 2026
- Type: Explainer

Inside D. E. Shaw group, a global investment and technology development firm, millions of compute workloads run monthly across its high-performance computing infrastructure. To support capacity planning and resource allocation, it collects task-level metrics for requested and utilized compute, producing millions of distinct time series that its previous observability platform could not accommodate. Engineers benchmarked databases on identical hardware and datasets; ClickHouse ingested approximately 3.5 million samples per second on one node versus roughly 480,000 for a competing solution, while similar queries completed in seconds instead of timing out. They retained InfluxDB line protocol, batched messages into ClickHouse, and built disk-based tooling to transform and stream historical data; the resulting four-server NVMe cluster stores about 68 TB compressed and sustains 530k records per second on average. Materialized views support capacity-planning dashboards, while OpenTelemetry tracing extends the platform to other observability workloads, with SQL migration and data modeling requiring engineering effort.


### [ClickHouse vs Prometheus for High Cardinality, Part 2: Cardinality in ClickHouse](https://yomu.fyi/post/clickhouse-vs-prometheus-for-high-cardinality-part-2-cardinality-in-cl.md)
- Company: [Clickhouse](https://yomu.fyi/company/clickhouse.md)
- Author: Rory Crispin, Dale McDiarmid
- Published: May 15, 2026
- Type: Explainer

Traditional time-series databases like Prometheus experience write amplification, memory overhead, and operational challenges when high-cardinality label combinations churn rapidly. ClickHouse alters these economics by abandoning dedicated series objects in favor of a wide events model, storing telemetry as rows in columnar tables with dynamic Map attributes and metric measurements. Dynamic attributes can be handled using sharded Map types alongside materialized columns and text indexes for frequently queried labels. This design trades ingestion overhead for query-time processing, relying on columnar compression, partition pruning, and parallel scans to compute aggregations on demand. ClickHouse avoids the ingest-side bottlenecks of high cardinality, though Prometheus remains preferable for moderate cardinality, native PromQL semantics, and single-series lookups.


### [ClickHouse vs Prometheus for High Cardinality, Part 1: Understanding the Problem](https://yomu.fyi/post/clickhouse-vs-prometheus-for-high-cardinality-part-1-understanding-the.md)
- Company: [Clickhouse](https://yomu.fyi/company/clickhouse.md)
- Author: Rory Crispin, Dale McDiarmid
- Published: May 14, 2026
- Type: Explainer

Observability systems frequently encounter high cardinality when metrics contain numerous unique label combinations across multidimensional cloud infrastructure. In Prometheus, every unique label combination instantiates an independent time series that incurs metadata overhead, requires in-memory memSeries registration, and continually expands inverted index posting lists. The ingestion engine stores samples in two-hour Head blocks using compressed 120-sample chunks with XOR-based encodings, but rapid series creation and elevated scrape frequencies multiply chunk allocations and memory consumption. When executing read operations, broad aggregations and regular expressions require intersecting expansive posting lists and decoding entire chunks sequentially because the engine cannot push value predicates directly into compressed storage blocks. Consequently, managing high-cardinality workloads in series-oriented architectures forces operational trade-offs between system stability and granular visibility into ephemeral components.


### [Postgres FDW: Pushdown is a negotiation](https://yomu.fyi/post/postgres-fdw-pushdown-is-a-negotiation.md)
- Company: [Clickhouse](https://yomu.fyi/company/clickhouse.md)
- Author: Kaushik Iska, David Wheeler, Philip Dubé
- Published: May 14, 2026
- Type: Explainer

Postgres Foreign Data Wrapper extensions allow PostgreSQL to query external datastores like ClickHouse by delegating execution to remote engines. Engineering pg\_clickhouse centers on pushdown decisions that determine whether SQL expressions run remotely or stream raw data back across the wire. Because pushdown depends on planner callbacks, deparser translations, and ClickHouse semantic compatibility, a single untranslated clause can block upper-level query pushdown entirely. Resolving pushdown barriers enables complex analytic queries to return hundreds of rows in milliseconds rather than pulling tens of millions of rows for local processing. Ultimately, pushdown development requires an iterative negotiation across differing SQL grammars, occasionally requiring the revocation of translations that fail to maintain strict equivalence.


### [ClickStack SQL Charting and Alerting](https://yomu.fyi/post/clickstack-sql-charting-and-alerting.md)
- Company: [Clickhouse](https://yomu.fyi/company/clickhouse.md)
- Author: Drew Davis, Dale McDiarmid
- Published: May 13, 2026
- Type: Announcement

ClickStack introduced SQL-based visualizations and SQL-based alerting to allow users to build charts and alerts using arbitrary ClickHouse SQL queries. Traditional query builders trade analytical flexibility for simplicity, preventing teams from easily expressing multi-stage computations like rolling baselines, anomaly detection, or dynamic SLO calculations. To maintain interactivity within dashboards, the system supports ClickHouse query parameters and macros that inject active time ranges, interval sizes, dashboard filters, and source tables. Furthermore, SQL-based alerting evaluates the numeric columns output by these queries, such as returning binary flags when values exceed statistical boundaries. By shifting computational logic directly into SQL, teams can implement complex operational checks without relying on static external thresholds.


### [ClickHouse Cloud: Fast, Updatable Lookups with the Join Table Engine](https://yomu.fyi/post/clickhouse-cloud-fast-updatable-lookups-with-the-join-table-engine.md)
- Company: [Clickhouse](https://yomu.fyi/company/clickhouse.md)
- Author: Hellmar Becker
- Published: May 12, 2026
- Type: Explainer

ClickHouse Cloud provides an in-memory Join table engine for precomputed hash-map lookups and joins, aimed at enriching append-only fact data with dimensions that change occasionally. With Join(ANY, LEFT, key), inserting another row for a key acts as an upsert, while joinGet and matching JOIN clauses use the in-memory structure. Open-source Join tables are not distributed and persist each INSERT batch as separate .bin files without automatic compaction, but ClickHouse Cloud transparently uses SharedJoin with MergeTree for ALL or ReplacingMergeTree for ANY. In the demonstrated enrichment query, duplicate inserts for id 1 leave value 42 visible, while the underlying table retains duplicates until merging; the in-memory load applies FINAL and always selects the latest entry, making ANY LEFT suitable for frequently updated dimensions.


### [Powering self-driving vehicle analytics at Avride with ClickHouse Cloud](https://yomu.fyi/post/powering-self-driving-vehicle-analytics-at-avride-with-clickhouse-clou.md)
- Company: [Clickhouse](https://yomu.fyi/company/clickhouse.md)
- Author: ClickHouse
- Published: May 11, 2026
- Type: Problem & solution

Avride’s expanding autonomous passenger vehicle and delivery robot fleet generated thousands of data points per minute, overwhelming its legacy Apache Iceberg and Parquet metadata indexing architecture. Iceberg’s optimistic concurrency model struggled with parallel writes, pushing ingestion latencies to hours or days, inflating query times to 10–20 seconds, and requiring raw data duplication across storage locations. To resolve these bottlenecks, Avride built a custom indexing and metrics warehouse powered by ClickHouse Cloud on AWS backed by Amazon S3 object storage. The new architecture dropped ingestion delays to seconds, reduced worst-case lookup latencies to under one second, eliminated the need for bespoke caching layers, and removed payload duplication. Beyond operational analytics, the unified ClickHouse platform now supports internal ride-replay debugging tools, simulation workflows, and high-cardinality vehicle C++ performance trace profiling.


### [ClickHouse Release 26.4](https://yomu.fyi/post/clickhouse-release-26-4.md)
- Company: [Clickhouse](https://yomu.fyi/company/clickhouse.md)
- Author: ClickHouse
- Published: May 8, 2026
- Type: Announcement

ClickHouse Release 26.4 introduces 39 new features, 45 performance optimizations, and 238 bug fixes, focusing on broader SQL compatibility and indexing improvements. The update expands standard SQL support by allowing VALUES clauses as table expressions with column aliases, PostgreSQL-style EXTRACT units, NATURAL JOIN, and SET TIME ZONE commands. For text search, LIKE and ILIKE pattern queries using splitByNonAlpha tokenizers scan inverted index dictionaries instead of executing full-table scans when the dedicated evaluation setting is active. The release also provides the JSONAllValues function to extract all leaf values from a JSON column into a string array, enabling text skip indexes that significantly reduce scanned data and improve query latency.


### [Introducing Postgres Query Insights in ClickHouse Cloud](https://yomu.fyi/post/introducing-postgres-query-insights-in-clickhouse-cloud.md)
- Company: [Clickhouse](https://yomu.fyi/company/clickhouse.md)
- Author: Amog Iska
- Published: May 7, 2026
- Type: Announcement

ClickHouse Cloud introduced Query Insights in preview for Managed Postgres to help teams diagnose slow database queries. Powered by the open-source extension pg\_stat\_ch, the tool streams per-statement telemetry directly into ClickHouse to enable fast aggregations across billions of execution rows. Postgres normalizes query literals into placeholders during the parse-analyze phase before telemetry leaves the database, preventing sensitive data exposure. Telemetry emission maintains around three percent producer overhead by utilizing a non-blocking try-lock on a shared-memory ring buffer. Users can examine high-level database health metrics, rank query patterns by runtime or latency percentiles, and inspect execution flyouts detailing disk spills, cache hits, and parallel worker behavior.


### [Agentic analytics starts with query-ready data: the write-side cost of Snowflake vs. ClickHouse](https://yomu.fyi/post/agentic-analytics-starts-with-query-ready-data-the-write-side-cost-of.md)
- Company: [Clickhouse](https://yomu.fyi/company/clickhouse.md)
- Author: Tom Schreiber, Lionel Palacin
- Published: May 6, 2026
- Type: Benchmark

Agentic analytics workflows introduce bursts of concurrent, low-latency analytical queries over continuously ingested data. Analytical query efficiency relies on columnar storage and chunk-level pruning, which require contiguous, sorted data to avoid full-table scans. Rather than evaluating warehouses solely at query runtime, this benchmark compares the write-side cost of maintaining query-ready data in ClickHouse and Snowflake during continuous ingestion at approximately one million rows per second. Snowflake relies on post-write clustering to organize data, whereas ClickHouse constructs sorted layouts on the write path and refines them via background merges. Across 100B, 200B, and 300B row checkpoints on the ClickBench dataset, ClickHouse achieved a query-ready layout at 22 times lower cost and delivered 28 times better write-side cost-performance.


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