ClickHouse

50,197 stars — tracking started 2026-10-02. Check back in a few days for growth history.

A distributed, column-oriented database built for real-time analytics at scale.

What it does

ClickHouse is a column-oriented database management system built for online analytical processing (OLAP) — running SQL aggregations over very large volumes of data and returning results fast enough for interactive dashboards and real-time reporting. It was built at Yandex, open-sourced in 2016, and is now developed by ClickHouse, Inc. alongside the open-source project.

Why people use it

• Scans and aggregates billions of rows with sub-second to low-second query times
• Scales horizontally across a cluster of nodes as data volume and query load grow
• Handles continuous, high-volume data ingestion (event streams, logs, metrics) well

Pros

• Proven at very large scale — in production at companies including Uber, eBay, and Comcast for analytics and reporting workloads
• Column-oriented storage with strong compression, which keeps both storage costs and scan times down on analytical workloads
• Runs as a single node for smaller workloads just as well as it does as a cluster

Cons

• A server to deploy and operate (or a managed/cloud offering to pay for), not an embeddable library — more operational overhead than a single-file database
• Transactional, multi-row-update workloads aren't what it's built for; it's optimized for append-heavy analytical data, not OLTP
• Tuning a cluster (sharding, replication, resource limits) for production has a real learning curve

Related Grove

Databases