fix: add more comment
@@ -344,7 +344,9 @@ impl DataBlock {
}
// If use_field_default_vals[i].is_some(), then DataBlock.column[i] = num_rows * DataField.default_value().
- // else, DataBlock.column[i] = chuck.columns[i].
+ // else, DataBlock.column[i] = chuck.column.
+ // For example, Schema.field is [a,b,c] and use_field_default_vals is [Some(), None, Some()],
+ // then the return block column will be [a.default_value()*num_rows, chunk.column[0], c.default_value()*num_rows].
pub fn create_with_schema_from_chunk<A: AsRef<dyn Array>>(
schema: &DataSchemaRef,
chuck: &ArrowChunk<A>,
