v.21.8New Feature

Add Reset Feature for Custom Settings to Default

Add an ability to reset a custom setting to default and remove it from the table's metadata. It allows rolling back the change without knowing the system/config's default. Closes #14449. #17769 (xjewer).
Added the ability to reset a custom setting to its default value and remove it from the table's metadata in ClickHouse.

Why it matters

This feature addresses the need to rollback a custom setting change on a table without requiring the user to know the system or configuration default value. It simplifies managing table settings by allowing users to revert changes cleanly and maintain accurate metadata.

How to use it

Users can reset a custom setting by using the appropriate command or interface that supports resetting custom table settings. Once reset, the setting will be removed from the table's metadata and revert to the system default automatically.