Method ReadOneRowGroup

cpp/src/parquet/arrow/reader.cc:1187–1200

  }

  static ::arrow::Future<RecordBatchGenerator> ReadOneRowGroup(
      ::arrow::internal::Executor* cpu_executor, std::shared_ptr<FileReaderImpl> self,
      const int row_group, const std::vector<int>& column_indices) {
    // Skips bound checks/pre-buffering, since we've done that already
    const int64_t batch_size = self->properties().batch_size();
    return self->DecodeRowGroups(self, {row_group}, column_indices, cpu_executor)
        .Then([batch_size](const std::shared_ptr<Table>& table)
                  -> ::arrow::Result<RecordBatchGenerator> {
          ::arrow::TableBatchReader table_reader(*table);
          table_reader.set_chunksize(batch_size);
          ARROW_ASSIGN_OR_RAISE(auto batches, table_reader.ToRecordBatches());
          return ::arrow::MakeVectorGenerator(std::move(batches));
        });
  }

  std::shared_ptr<FileReaderImpl> arrow_reader_;
  ::arrow::internal::Executor* cpu_executor_;