[GitHub] [rocketmq] cserwen commented on issue #3443: [POP] PopReviveService will consume reviveTopic repeatedly when use pop model to consume.

[GitBox <gi...@apache.org>]

cserwen commented on issue #3443:
URL: https://github.com/apache/rocketmq/issues/3443#issuecomment-957036448


   > In order to prevent the message from being lost. Revive topic queue Offset update needs to pass ck msg. Revive topic contains both ck msg and ack msg. If the offset is updated directly by the number of Revive topic queue messages, there is a possibility of message loss. For example, some ck msgs are not confirmed by ack msg. , And without sending the retry topic, the offset of the receive topic is updated directly. There is a possibility of repetition of ack msg due to the network or other reasons. The message corresponding to ack has been acked, and ack will be consumed repeatedly, but it has no effect. These ack msg will not be consumed repeatedly when the new ck msg is updated.
   
   @odbozhou Thanks for the explanation, but I have two questions:
   
   - The offset was updated after putting messages into retry topic. Is it possible to fail putting msgs?
   - Even if the above example happens, updating the offset by the ck msgs and updating it by the number of Revive topic queue messages are the same, because the ck msgs will be consumed only once. So I think updating the consume offset by the number of msgs directly will be better.


-- 
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.

To unsubscribe, e-mail: dev-unsubscribe@rocketmq.apache.org

For queries about this service, please contact Infrastructure at:
users@infra.apache.org