private String getColumnNames(final String columnTypes) {
    StringBuilder columnNames = new StringBuilder();

    /* Construct a string of column names based on the number of column types */
    List<TypeInfo> columnTypesList = TypeInfoUtils.getTypeInfosFromTypeString(columnTypes);
    for (int i=0; i < columnTypesList.size(); i++) {
      if (i > 0) {
        columnNames.append(",");
      }
      columnNames.append("c" + i);
    }

    return columnNames.toString();
  }
We use LazySimpleSerDe to generate our testing rows.
itests/hive-jmh/src/main/java/org/apache/hive/benchmark/storage/ColumnarStorageBench.java