public int getDataColumnCount() {
    return dataColumnCount;
  }
Return a batch with the specified number of columns and rows.
Only call this constructor directly for testing purposes.
Batch size should normally always be defaultSize.

@param numCols the number of columns to include in the batch
@param size  the number of rows to include in the batch
storage-api/src/java/org/apache/hadoop/hive/ql/exec/vector/VectorizedRowBatch.java