int blockSize = (int) DefaultConfiguration.getDefaultConfiguration().getMemoryInBytes(Property.TABLE_FILE_BLOCK_SIZE);
Writer small = new RFile.Writer(new CachableBlockFile.Writer(fs, new Path(smallName), "gz", conf), blockSize);
small.startDefaultLocalityGroup();
Writer large = new RFile.Writer(new CachableBlockFile.Writer(fs, new Path(largeName), "gz", conf), blockSize);
large.startDefaultLocalityGroup();
iter.seek(new Range(), new ArrayList<ByteSequence>(), false);
while (iter.hasTop()) {
Key key = iter.getTopKey();
Value value = iter.getTopValue();