presto-raptor-legacy/src/main/java/io/prestosql/plugin/raptor/legacy/storage/organization/ShardCompactor.java/ShardCompactor/isNullOrEmptyPage
class ShardCompactor:    private static boolean isNullOrEmptyPage(Page nextPage)
    {
        return nextPage == null || nextPage.getPositionCount() == 0;
    }