Apache Druid 31.0 marks a significant advancement in the open-source distributed database, aimed at enhancing real-time analytics at scale. This release features over 525 commits from 45 contributors and introduces a multi-profile era, allowing for customizable performance and cost adjustments to accommodate diverse use cases. Notably, it introduces the new Dart query profile, designed to handle highly complex queries, such as high-cardinality GROUP BY and large joins, using a revolutionary query engine that leverages multi-threaded workers and in-memory shuffles. Enhancements also include support for SQL window functions within the multi-stage query (MSQ) engine, offering solutions for categorized analysis like cumulative sums and trend analysis. Additionally, Druid 31 improves data compaction processes with features such as concurrent append and replace, supervisor-based compaction scheduling, and MSQ-based auto-compaction, all aimed at optimizing query efficiency and resource management. The release also enhances the Explore view for interactive data exploration and includes an access control UI, broadening data accessibility for non-SQL users. With these updates, Druid 31 aims to expand its utility and efficiency for developers and analysts alike, while continuing to evolve its features and address any stability or functionality gaps in future releases.