code: private void doIncrementHash(String key, String hashKey, long amount, String bookkeepingKey) {
  		long newValue = hashOperations.increment(key, hashKey, amount);
  		// TODO: the following test does not necessarily mean that the hash
  		// is new, just that the key inside that hash is new. So we end up
  		// calling add more than needed
  		if (newValue == amount) {
  			setOperations.add(bookkeepingKey, key);
  		}
  	}
docs: Internally increments the given hash key, keeping track of created hash for a given counter, so they can be
  cleaned up when needed.