@Override
 public List<UnderReplicatedBlock> findByLevel(int level, int offset, int count)
     throws StorageException {
   HopsSession session = connector.obtainSession();
   HopsQueryBuilder qb = session.getQueryBuilder();
   HopsQueryDomainType<UnderReplicatedBlocksDTO> dobj =
       qb.createQueryDefinition(UnderReplicatedBlocksDTO.class);
   HopsPredicate pred = dobj.get("level").equal(dobj.param("level"));
   dobj.where(pred);
   HopsQuery<UnderReplicatedBlocksDTO> query = session.createQuery(dobj);
   query.setParameter("level", level);
   query.setOrdering(Query.Ordering.ASCENDING, "level", "timestamp");
   query.setLimits(offset, count);
   return createUrBlockList(query.getResultList());
 }