@Override
	public void delete(String id) {
		String metricMetaKey = bookkeepingKeyFor(id);
		super.delete(id);
		Set<String> otherKeys = setOperations.members(metricMetaKey);
		// Add metric-meta SET's key
		otherKeys.add(metricMetaKey);
		redisOperations.delete(otherKeys);
	}
Will convert a (possibly sparse) map whose keys are String versions of numbers between 0 and size, to an array.
spring-xd-analytics/src/main/java/org/springframework/xd/analytics/metrics/redis/RedisAggregateCounterRepository.java