Added System.detached_parts Table Containing Information About Detached Parts of Mergetree Tables

Why it matters

This feature allows users to monitor and inspect detached parts of MergeTree tables, which are data parts no longer active in the main table but kept detached for operations such as manual intervention, backup, or troubleshooting. This helps in managing storage, understanding table state, and diagnosing data-related issues.

How to use it

Users can query the system.detached_parts table to retrieve metadata and details about detached parts in their MergeTree tables. Simply run a SELECT query on system.detached_parts to see relevant information.