Documentation Index
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Welcome to QuestDB
QuestDB is an open-source time-series database offering blazingly fast ingestion and dynamic, low-latency SQL queries. Built for performance, QuestDB delivers a multi-tier storage engine and achieves high performance via column-oriented storage, parallelized vector execution, SIMD instructions, and low-latency techniques.Why QuestDB?
QuestDB combines the familiarity of SQL with specialized time-series features, making it ideal for applications that demand both speed and flexibility.Key Features
High-Performance Ingestion
Low-latency, high-throughput ingestion from single events to millions per second
Time-Series SQL Extensions
Advanced SQL features like ASOF JOIN, WINDOW JOIN, HORIZON JOIN, SAMPLE BY, and LATEST ON
SIMD-Accelerated Execution
Parallel execution with SIMD acceleration for maximum query performance
Multi-Tier Storage
Intelligent storage: WAL → native columnar → Parquet (time-partitioned and time-ordered)
Multiple Protocols
PostgreSQL wire protocol (PGwire), REST API, and InfluxDB Line Protocol (ILP)
Open Source
Apache 2.0 license with open formats—no vendor lock-in
Ideal Use Cases
QuestDB excels in demanding time-series workloads:- Financial market data - Tick data, trades, order books, OHLC
- Sensor and telemetry data - High cardinality data streams from IoT devices
- Real-time dashboards - Live monitoring and analytics with continuous streaming
Beyond Performance
With QuestDB, you don’t need to worry about:- Out-of-order data handling
- Deduplication and exactly-once semantics
- Continuous streaming ingest with concurrent queries
- Low-latency streaming data
- Volatile and “bursty” data patterns
- Schema changes on the fly while streaming data
Architecture Highlights
QuestDB is implemented in zero-GC Java and C++, with QuestDB Enterprise including additional components in Rust. The core engine uses:- Column-oriented storage for optimal compression and vectorized operations
- Native C/C++ libraries for performance-critical operations via JNI
- Zero-allocation data structures on hot paths to avoid garbage collection overhead
- Time-partitioned storage for efficient data lifecycle management
Getting Started
Quick Start
Get QuestDB running in under 5 minutes with Docker
Installation Guide
Install QuestDB using Docker, Homebrew, binaries, or build from source
Ingestion Methods
Learn about ingestion clients and connection methods
SQL Reference
Explore QuestDB’s SQL dialect and time-series extensions