Support for ALTER TABLE PARTITION Query in MergeTree Tables

Why it matters

This feature enables users to replace or attach partitions in MergeTree tables, simplifying data management tasks such as partition reorganization, data recovery, or synchronization. It helps maintain table integrity and manage large datasets more efficiently.

How to use it

Users can apply the feature by executing the ALTER TABLE command with either the REPLACE PARTITION or ATTACH PARTITION clause on a MergeTree table, for example:

ALTER TABLE <table_name> REPLACE PARTITION <partition_value> FROM <source_table>

or

ALTER TABLE <table_name> ATTACH PARTITION <partition_value>