Apache Druid
A scalable OLAP database delivering sub-second queries on streaming and batch data with high concurrency and low infrastructure costs.
Apache Druid is an open-source alternative to:
Apache® Druid
Apache Druid is a high-performance, real-time analytics database designed for sub-second OLAP queries on massive datasets. It combines streaming and batch data processing with a distributed architecture that scales effortlessly while maintaining consistent performance.
Key Features
- Sub-second Queries: Execute OLAP queries in milliseconds on high-cardinality datasets with billions to trillions of rows without pre-caching.
- High Concurrency: Supports 100s to 100,000s queries per second with consistent performance and minimal infrastructure overhead.
- Real-time & Historical Insights: Native integration with Apache Kafka and Amazon Kinesis enables query-on-arrival at millions of events per second.
- Interactive Query Engine: Utilizes scatter/gather for high-speed queries with data preloaded into memory or local storage.
- Tiering & QoS: Configurable tiering with quality of service guarantees priority and avoids resource contention.
- Optimized Data Format: Automatic columnarization, time-indexing, dictionary encoding, and type-aware compression.
- Elastic Architecture: Loosely coupled components for ingestion, queries, and orchestration with deep storage layer for easy scaling.
- True Stream Ingestion: Connector-free integration with streaming platforms for low-latency, high-scalability ingestion.
- Non-stop Reliability: Continuous backup, automated recovery, and multi-node replication ensure high availability.
- Schema Auto-Discovery: Automatically detects and updates column names and data types upon ingestion.
- Flexible Joins Support: Supports join operations during ingestion and query-time execution.
- SQL Support: Familiar SQL API for end-to-end data operations across ingestion, transformation, and querying.
Tech / Self-Hosting
Apache Druid is an open-source project under the Apache Software Foundation. It can be self-hosted on any infrastructure and is designed for horizontal scaling. The project provides comprehensive documentation for deployment, configuration, and security best practices. Druid is proven in production at leading companies worldwide at massive scale.
License: Apache License 2.0
Hosting: Self-hosted (cloud, on-premises, or hybrid)
Documentation: Available at https://druid.apache.org/docs/latest/
Community: Active open-source community with Slack, meetups, and extensive documentation.