QuestDB Time Series Database

QuestDB is an open-source time-series database designed for high-performance ingestion and fast SQL queries on time-series and financial market data. Developed by QuestDB team led by Nicolas iveron and Constantin Pleniceanu since 2019, QuestDB uses a column-oriented storage engine optimized for time-series workloads. Key features: high-performance ingestion achieving millions of rows per second via the InfluxDB Line Protocol (ILP) and PostgreSQL wire protocol, enabling drop-in compatibility with existing InfluxDB and PostgreSQL tooling. SQL-first query interface with time-series extensions including SAMPLE BY for time-based downsampling, LATEST ON for retrieving the most recent records per series, ASOF JOIN for time-series alignment, and SAMPLE BY aggregation for computing OHLC candles. Columnar storage with SIMD-optimized vectorized execution for fast aggregation queries, achieving sub-millisecond query latency on millions of rows. Zero-GC Java implementation using off-heap memory management for predictable latency without garbage collection pauses. Time-series specific data model with designated timestamp columns enabling efficient time-range scans and partition pruning. Partitioning by day, week, or month for efficient data lifecycle management and query pruning. Web console built-in for exploring data, running SQL queries, and visualizing results with charts and CSV export. PostgreSQL wire protocol compatibility enabling connection from psql, DBeaver, Grafana, and any PostgreSQL client. InfluxDB Line Protocol compatibility for seamless migration from InfluxDB with zero code changes. REST API for inserting data via HTTP with JSON and CSV payloads. ACID transactions for write consistency. Standalone single-process deployment requiring no external dependencies. Cross-platform on Linux, macOS, Windows, and Docker. Used in financial services for market data, IoT telemetry, application monitoring, and real-time analytics. Open source under Apache 2.0.