【RedisCluster】redis-cluster mget測試

測試用例：

@Test
    void redisMgetTest(){
        List<String> list=new ArrayList();
        list.add("lcc");
        list.add("ccl");
        list.add("clc");
        List<Object> res=redisTemplate.opsForValue().multiGet(list);
        for (Object o:res){
            System.out.println(o);
        }
    }

 執行結果：

 

還是能跑的，調試看一下是怎么玩的吧

 

先判斷是否在同一個slot，如果是的話估計就和standalone一樣，如果不是交給

org.springframework.data.redis.connection.ClusterCommandExecutor#executeMultiKeyCommand：

/**
	 * Run {@link MultiKeyClusterCommandCallback} with on a curated set of nodes serving one or more keys.
	 *
	 * @param cmd must not be {@literal null}.
	 * @return never {@literal null}.
	 * @throws ClusterCommandExecutionFailureException
	 */
	public <S, T> MultiNodeResult<T> executeMultiKeyCommand(MultiKeyClusterCommandCallback<S, T> cmd,
			Iterable<byte[]> keys) {

		Map<RedisClusterNode, PositionalKeys> nodeKeyMap = new HashMap<>();

		int index = 0;
　　　　　　　　　　//聚合每個node下面所有的key
		for (byte[] key : keys) {
			for (RedisClusterNode node : getClusterTopology().getKeyServingNodes(key)) {
				nodeKeyMap.computeIfAbsent(node, val -> PositionalKeys.empty()).append(PositionalKey.of(key, index++));
			}
		}

　　　　　　　　　　//用並行的方式請求各個redis-server
		Map<NodeExecution, Future<NodeResult<T>>> futures = new LinkedHashMap<>();
		for (Entry<RedisClusterNode, PositionalKeys> entry : nodeKeyMap.entrySet()) {

			if (entry.getKey().isMaster()) {
				for (PositionalKey key : entry.getValue()) {
					futures.put(new NodeExecution(entry.getKey(), key),
							executor.submit(() -> executeMultiKeyCommandOnSingleNode(cmd, entry.getKey(), key.getBytes())));
				}
			}
		}

		return collectResults(futures);
	}

 可以看到這里的實現方式是我們上篇文章提到的並行I/O請求的方式，而不是hash_tag(不是很理解這個)