Add Builtin HTML Page for Visualizing Merges at /merges Path

Why it matters

This feature helps users monitor and understand the merge operations within ClickHouse, which are crucial for optimizing performance and managing data storage. By providing a visual interface, it makes it easier to track merge progress and diagnose related issues.

How to use it

Access the merge visualization by opening the /merges URL on your ClickHouse server's HTTP interface in a web browser. No additional configuration is needed.