Support alter delete mutations

Why it matters

This feature enables users to perform delete mutations on Iceberg tables stored in the merge-on-read format, addressing the limitation where such operations were previously unsupported. It improves data management flexibility and mutation capabilities for Iceberg integration in ClickHouse.

How to use it

Users can execute ALTER TABLE ... DELETE mutations on Iceberg tables configured with the merge-on-read format as they would on other supported table formats in ClickHouse. No additional configuration is required other than using Iceberg tables with the merge-on-read setting.