private long computeProjectionSize(List<OrcProto.Type> fileTypes,
          List<OrcProto.ColumnStatistics> stats, boolean[] fileIncluded) throws FileFormatException {
      // Exclude ORC <root> and ACID <row> struct elements to avoid full schema size estimation  
      final List<Integer> internalColIds;
      if (fileIncluded == null) {
        internalColIds = IntStream.range(1, fileTypes.size())
            .boxed().collect(Collectors.toList());
      } else {
        internalColIds = IntStream.range(1, fileTypes.size()).filter(i -> fileIncluded[i])
            .filter(i -> i != OrcRecordUpdater.ROW + 1 || isOriginal) 
            .boxed().collect(Collectors.toList());
      }
      return ReaderImpl.getRawDataSizeFromColIndices(internalColIds, fileTypes, stats);
    }
Divide the adjacent stripes in the file into input splits based on the
block size and the configured minimum and maximum sizes.
ql/src/java/org/apache/hadoop/hive/ql/io/orc/OrcInputFormat.java