redis之pipeline

redis之pipeline

When we have to send multiple commands, we can pack them together in one request and save connection overhead by using pipelines, it is essentially a network optimization. As long as the operations are mutually independent, we can take advantage of this technique:

Redis 是基于client-server的请求响应模型，一条命令的执行：

• 发送命令
• 命令排队
• 命令执行
• 接收返回结果

RTT - round trip time， 如果发送N次命令，等待上一条命令应答后再执行，这中间不仅仅多了RTT（Round Time Trip），而且还频繁的调用系统IO，发送网络请求。

pipeline只要是提升执行效率，减少网络IO。

jedis pipeline support

public void mdel(List<String> keys){
  Jedis jedis = new Jedis("127.0.0.1");
  // 创建Pipeline对象
  Pipeline pipeline = jedis.pipelined();
  for (String key : keys){
    // 组装命令
    pipeline.del(key);
  }
  // 执行命令
  pipeline.sync();
}

notes： redis 提供批量操作命令 mge，mset，同样实现缩减rtt的目的。

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https://redislabs.com/ebook/part-2-core-concepts/chapter-4-keeping-data-safe-and-ensuring-performance/4-5-non-transactional-pipelines/

https://redis.io/topics/pipelining