public UnsafeExternalRowSorter(

      StructType schema,

      Ordering<InternalRow> ordering,

      PrefixComparator prefixComparator,

      PrefixComputer prefixComputer,

      long pageSizeBytes) throws IOException {

    this.schema = schema;

    this.prefixComputer = prefixComputer;

    final SparkEnv sparkEnv = SparkEnv.get();

    final TaskContext taskContext = TaskContext.get();

    sorter = UnsafeExternalSorter.create(

      taskContext.taskMemoryManager(),

      sparkEnv.blockManager(),

      taskContext,

      new RowComparator(ordering, schema.length()),

      prefixComparator,

      pageSizeBytes

    );

  }