This blog post provides several ways to monitor and troubleshoot SELECT queries in ClickHouse, including global overviews of the cluster setup, monitoring expensive queries, comparing metrics between two queries, and performing a deep dive into query execution. It also discusses troubleshooting common issues such as TOO_MANY_SIMULTANEOUS_QUERIES, stuck or failed queries, and provides guidance on using the ClickHouse SQL-console to inspect query execution details. The post recommends proactively monitoring query performance and behavior, and suggests tools like Grafana for alerting and visualization. Overall, this post aims to help users better understand their SELECT queries, identify performance issues, and improve query optimization.