private static String[] extractNeededColNames(
      List<OrcProto.Type> types, String columnNamesString, boolean[] include, boolean isOriginal) {
    return getSargColumnNames(columnNamesString.split(","), types, include, isOriginal);
  }
Take the configuration and figure out which columns we need to include.
@param readerSchema the types for the reader
@param conf the configuration
ql/src/java/org/apache/hadoop/hive/ql/io/orc/OrcInputFormat.java