public MemtableUnfilteredPartitionIterator makePartitionIterator(
      final ColumnFilter columnFilter, final DataRange dataRange, final boolean isForThrift) {
    AbstractBounds<PartitionPosition> keyRange = dataRange.keyRange();

    boolean startIsMin = keyRange.left.isMinimum();
    boolean stopIsMin = keyRange.right.isMinimum();

    boolean isBound = keyRange instanceof Bounds;
    boolean includeStart = isBound || keyRange instanceof IncludingExcludingBounds;
    boolean includeStop = isBound || keyRange instanceof Range;
    Map<PartitionPosition, AtomicBTreePartition> subMap;
    if (startIsMin)
      subMap = stopIsMin ? partitions : partitions.headMap(keyRange.right, includeStop);
    else
      subMap =
          stopIsMin
              ? partitions.tailMap(keyRange.left, includeStart)
              : partitions.subMap(keyRange.left, includeStart, keyRange.right, includeStop);

    int minLocalDeletionTime = Integer.MAX_VALUE;

    // avoid iterating over the memtable if we purge all tombstones
    if (cfs.getCompactionStrategyManager().onlyPurgeRepairedTombstones())
      minLocalDeletionTime = findMinLocalDeletionTime(subMap.entrySet().iterator());

    final Iterator<Map.Entry<PartitionPosition, AtomicBTreePartition>> iter =
        subMap.entrySet().iterator();

    return new MemtableUnfilteredPartitionIterator(
        cfs, iter, isForThrift, minLocalDeletionTime, columnFilter, dataRange);
  }
 public UnfilteredRowIterator next() {
   Map.Entry<PartitionPosition, AtomicBTreePartition> entry = iter.next();
   // Actual stored key should be true DecoratedKey
   assert entry.getKey() instanceof DecoratedKey;
   DecoratedKey key = (DecoratedKey) entry.getKey();
   ClusteringIndexFilter filter = dataRange.clusteringIndexFilter(key);
   return filter.getUnfilteredRowIterator(columnFilter, entry.getValue());
 }