Method project_batch

datafusion/datasource-parquet/src/push_decoder.rs:218–238

(&self, batch: &RecordBatch)

    }

    fn project_batch(&self, batch: &RecordBatch) -> Result<RecordBatch> {
        let mut batch = self.projector.project_batch(batch)?;
        if self.replace_schema {
            // Ensure the output batch has the expected schema.
            // This handles things like schema level and field level metadata, which may not be present
            // in the physical file schema.
            // It is also possible for nullability to differ; some writers create files with
            // OPTIONAL fields even when there are no nulls in the data.
            // In these cases it may make sense for the logical schema to be `NOT NULL`.
            // RecordBatch::try_new_with_options checks that if the schema is NOT NULL
            // the array cannot contain nulls, amongst other checks.
            let (_stream_schema, arrays, num_rows) = batch.into_parts();
            let options = RecordBatchOptions::new().with_row_count(Some(num_rows));
            batch = RecordBatch::try_new_with_options(
                Arc::clone(&self.output_schema),
                arrays,
                &options,
            )?;
        }
        Ok(batch)
    }
}