Grafana Mimir 3.0 introduces significant performance improvements, including a new query engine and a decoupled architecture to better handle read and write operations. These changes enhance reliability, reduce resource usage, and optimize costs for large-scale deployments. Upgrading requires careful planning due to the architectural shifts.

Grafana Mimir has introduced the Mimir Query Engine (MQE) to improve memory efficiency and performance compared to the traditional PromQL engine. Launched with Grafana Mimir 2.17, MQE processes queries in a streaming manner, significantly reducing peak memory utilization and execution time while maintaining compatibility with existing PromQL features. The new engine also underwent rigorous correctness testing to ensure accurate results.