public void copyByValue(VectorizedRowBatch inBatch, int inBatchIndex, VectorizedRowBatch outBatch, int outBatchIndex) {
    for (CopyRow copyRow : subRowToBatchCopiersByValue) {
      copyRow.copy(inBatch, inBatchIndex, outBatch, outBatchIndex);
    }
  }
This class copies specified columns of a row from one VectorizedRowBatch to another.
ql/src/java/org/apache/hadoop/hive/ql/exec/vector/VectorCopyRow.java