v.25.7New Feature

Read Iceberg data files by field ids

Read Iceberg data files by field ids. This improves compatibility with Iceberg: the fields can be renamed in the metadata while being mapped to the different names in the underlying Parquet files. This closes #83065. #83653 (Konstantin Vedernikov).
ClickHouse now supports reading Iceberg data files by field IDs, enabling better compatibility with Iceberg table metadata.

Why it matters

This feature addresses the issue where fields in Iceberg metadata can be renamed without affecting the underlying Parquet files. By using field IDs to map fields instead of relying solely on field names, it ensures accurate data reading and improves interoperability with Iceberg table formats.

How to use it

This improvement is automatically applied when reading Iceberg tables with ClickHouse. Users do not need to set any specific configuration; the reading process will internally map fields by their IDs to handle renamed columns correctly.