prune_parquet_metadata trims each retained footer down to the projected and predicate columns, shrinking the metadata that Polars Cloud serializes to workers. It matches columns by name.
In Iceberg, columns are identified by field ID, which is stable across renames. If a column mapping exists, we don't do the pruning, because this means that there were column renames.
This popped up as a followup in #29295
prune_parquet_metadata trims each retained footer down to the projected and predicate columns, shrinking the metadata that Polars Cloud serializes to workers. It matches columns by name.
In Iceberg, columns are identified by field ID, which is stable across renames. If a column mapping exists, we don't do the pruning, because this means that there were column renames.
This popped up as a followup in #29295