Even More Blazin' Fast PromQL

Tom Wilkie's blog post discusses advancements in optimizing Prometheus query language (PromQL) for high-cardinality data and single-thread limitations. At KubeCon San Diego, Wilkie presented techniques to improve query performance by leveraging time-based parallelization, caching, and aggregation sharding, which significantly reduce query latency. These methods enable executing PromQL queries with lower latency, crucial for applications like capacity planning and performance analysis. The innovations are applied in Grafana Cloud's Prometheus service, based on the open-source Cortex project, which aims for full Prometheus compatibility. Despite Prometheus's single-threaded design, these enhancements demonstrate how parallelization and sharding can be effectively implemented, benefiting not only Cortex but also other systems like Thanos. The post provides a walkthrough to test these improvements, showing a significant reduction in query execution time and highlighting ongoing efforts to enhance query planning and execution across the Prometheus ecosystem.