private ParquetMetadata readFooterFromFile(final Path file, final FileSystem fs,
      final FileStatus stat, MetadataFilter filter) throws IOException {
    InputFile inputFile = new InputFile() {
      @Override
      public SeekableInputStream newStream() throws IOException {
        return HadoopStreams.wrap(fs.open(file));
      }
      @Override
      public long getLength() {
        return stat.getLen();
      }
    };
    return ParquetFileReader.readFooter(inputFile, filter);
  }
The total number of rows this RecordReader will eventually read. The sum of the
rows of all the row groups.
ql/src/java/org/apache/hadoop/hive/ql/io/parquet/vector/VectorizedParquetRecordReader.java