Skip to content

Update RocketMQ.md #1260

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
Snailclimb merged 1 commit into from
Jun 30, 2021
+3 −1
Merged

Update RocketMQ.md #1260

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
4 changes: 3 additions & 1 deletion docs/system-design/distributed-system/message-queue/RocketMQ.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -200,6 +200,8 @@

因为我们刚刚画的仅仅是一个消费者组，我们知道在发布订阅模式中一般会涉及到多个消费者组，而每个消费者组在每个队列中的消费位置都是不同的。如果此时有多个消费者组，那么消息被一个消费者组消费完之后是不会删除的(因为其它消费者组也需要呀)，它仅仅是为每个消费者组维护一个 **消费位移(offset)** ，每次消费者组消费完会返回一个成功的响应，然后队列再把维护的消费位移加一，这样就不会出现刚刚消费过的消息再一次被消费了。

这里我有一个疑问：上面说【一个队列只会被一个消费者消费】下面说说【那么消息被一个消费者组消费完之后是不会删除的(因为其它消费者组也需要呀)】，讲不通啊，消息在不同队列上是重复的吗？

![](https://my-blog-to-use.oss-cn-beijing.aliyuncs.com/2019-11/16ef3857fefaa079.jpg)

可能你还有一个问题，**为什么一个主题中需要维护多个队列** ？
Expand Down Expand Up @@ -451,4 +453,4 @@ emmm，是不是有一点复杂🤣，看英文图片和英文文档的时候就

等等。。。

> 如果喜欢可以点赞哟👍👍👍。
> 如果喜欢可以点赞哟👍👍👍。