QuestDB

QuestDB is a high-performance open source database for time series. The project is built from scratch in Java and C++, with no dependencies, and is 100% free from garbage collection. The database is optimized for time series with high-throughput ingestion over InfluxDB Line Protocol and allows users to use SQL as a query language via PostgreSQL wire or REST API. Developers rely on QuestDB as the analytic backbone of real-time systems ranging from FinTech to machine learning, IoT, and application monitoring. Fortune 500 companies such as Airbus and Yahoo deploy QuestDB for large-scale, data-intensive production systems, some of which serve close to a billion users.