ClickHouse

Column-oriented database management system optimized for online analytical processing. Stores data by column instead of row, enabling high compression and fast aggregations over large datasets without indexes.

Adopted by Cloudflare, Spotify, and Uber for log analytics, metrics, and real-time dashboards. ClickHouse excels at scan-heavy workloads: filtering and aggregating billions of rows in seconds using vectorized execution and SIMD.

Key capabilities:

• SQL interface with extensions for arrays, nested structures, and approximate algorithms
• Real-time ingestion via Kafka, files, or HTTP
• Replication and sharding for distributed deployments
• Cloud deployment options for managed operation
• Integrations with visualization tools and data pipelines

Teams use ClickHouse for event analytics, observability backends, A/B test storage, and time-series metrics. Developers query via HTTP, native protocol, or drivers for major languages, and often pair it with Kafka or object storage for high-throughput ingestion.