public static List<FieldSchema> getFieldSchemasFromRowSchema(RowSchema row,
      String fieldPrefix) {
    List<ColumnInfo> c = row.getSignature();
    return getFieldSchemasFromColumnInfo(c, fieldPrefix);
  }
Convert the RowSchema to FieldSchema list.
ql/src/java/org/apache/hadoop/hive/ql/plan/PlanUtils.java