What is druid?

Apache Druid is a database built for answering questions about large amounts of data very quickly. It is designed for situations where you need fast answers from data that is arriving continuously, such as tracking user activity on a website in real time or monitoring events as they happen. Think of it as a tool that sits between raw incoming data and the people or dashboards that need to query it immediately. Druid is particularly good at handling high traffic queries, like powering the charts and tables inside a product dashboard that many users might be viewing at once. It can ingest data from streaming sources (data arriving in a continuous flow) and from batch sources (large files loaded at scheduled times). Once data is loaded, queries typically return in a fraction of a second even over billions of rows. The project includes a web console where you can set up data loading, browse what data is stored, and run queries without writing code. For developers, it also exposes SQL and HTTP interfaces so applications can connect to it directly. It runs as a cluster of separate processes, meaning you can scale different parts of the system independently depending on where the bottleneck is. Druid is an open source project under the Apache Software Foundation, so it is free to use and has an active community. Official documentation, quickstart guides for running it locally or in a container environment, and community forums are all linked from the repository.