public static int getPositionFromInternalName(String internalName) {
    Pattern internalPattern = Pattern.compile("_col([0-9]+)");
    Matcher m = internalPattern.matcher(internalName);
    if (!m.matches()){
      return -1;
    } else {
      return Integer.parseInt(m.group(1));
    }
  }
@return the user name set in hadoop.job.ugi param or the current user from System
@throws IOException
common/src/java/org/apache/hadoop/hive/conf/HiveConf.java