Apache IoTDB is a column-oriented open-source, time-series database (TSDB) management system written in Java. It has both edge and cloud versions, provides an optimized columnar file format for efficient time-series data storage, and TSDB with high ingestion rate, low latency queries and data analysis support. It is specially optimized for time-series oriented operations like aggregations query, downsampling and sub-sequence similarity search. The name IoTDB comes from Internet of Things (IoT) Database, which means it was designed as an IoT-native TSDB that resolves the pain points of the typical IoT scenarios, including massive data generation, high frequency sampling, out-of-order data, specific analytics requirements, high costs of storage and operation & maintenance, low computational power of IoT devices.