presto-main/src/main/java/io/prestosql/operator/SortedPositionLinks.java/PositionComparator/PositionComparator
class PositionComparator:        PositionComparator(PagesHashStrategy pagesHashStrategy, LongArrayList addresses)
        {
            this.pagesHashStrategy = pagesHashStrategy;
            this.addresses = addresses;
        }