Strengthening Apache Pinot's Query Processing Engine with Adaptive Server Selection and Runtime ## Query Killing

Apache Pinot, a real-time, distributed OLAP database, encountered resiliency challenges in its large production deployment due to server failures, slowness, and unpredictable query patterns. To ensure adherence to strict SLAs, enhancements were made to its Query Processing framework through two key features: Intelligent Query Routing and Runtime Query Killing. Intelligent Query Routing replaces the traditional round-robin server query distribution with a dynamic approach based on continuous server performance metrics. This adaptive method proactively routes queries to more efficient servers, reducing the need for manual intervention and preserving availability during transient server issues. Runtime Query Killing addresses the issue of complex queries causing Out of Memory errors and avail