v.21.1New Features

Add Asynchronous Metrics for MergeTree Tables

Add asynchronous metrics on total amount of rows, bytes and parts in MergeTree tables. This fix #11714. #17639 (flynn).
Adds asynchronous metrics to report the total amount of rows, bytes, and parts in MergeTree tables.

Why it matters

This feature provides accurate, continuously updated metrics for MergeTree tables, solving the problem of lacking real-time insights into table size and composition. It helps users monitor their data more effectively and optimize resource usage.

How to use it

The metrics are collected asynchronously and available automatically when using MergeTree tables without additional configuration. Users can query these metrics through system tables or monitoring tools integrated with ClickHouse.