presto-raptor-legacy/src/main/java/io/prestosql/plugin/raptor/legacy/storage/organization/ShardCompactor.java/ShardCompactor/next
class ShardCompactor:        @Override
        public Row next()
        {
            if (!hasNext()) {
                throw new NoSuchElementException();
            }

            Row row = extractRow(currentPage, currentPosition, columnTypes);
            currentPosition++;
            return row;
        }