presto-main/src/main/java/io/prestosql/operator/PagesRTreeIndex.java/PagesRTreeIndex/isJoinPositionEligible
class PagesRTreeIndex:    @Override
    public boolean isJoinPositionEligible(int joinPosition, int probePosition, Page probe)
    {
        return filterFunction == null || filterFunction.filter(joinPosition, probePosition, probe);
    }