[ROCKETMQ-105] Implementation of consumerOffset and maxOffset are counter-intuitive

• Type: Wish
• Status: Closed
• Priority: Minor
• Resolution: Feedback Received
• Affects Version/s: 4.0.0-incubating
• Fix Version/s: 4.2.0
• Component/s: rocketmq-broker, rocketmq-client, rocketmq-store
• Assignee: Xinyu Zhou
• Reporter: Jaskey Lam
• Created: 16/Feb/17 09:59
• Updated: 13/Dec/17 12:26
• Resolved: 13/Dec/17 12:26

Description

This issue does not affect any functionalites, but it indeed is a problem for user to understand the principle of RocketMQ.

• ConsumerOffset:

User might consider `ConsumerOffset` is the offset where consumer has consumed. for example if CG1 have a consumer offset 100 of topicA-q1, I may propabaly consider message with offset 100 has been cosumed. But actully, it is not. The message with offset 100 is the next target offset to pull from.

• Max Offset

User might consider this is the offset of the latest message in a queue. But it is not, it is indicating that next offset when new message arrived.

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If possible , any of the below two things should be taken into consideration

1. the implementation should be changed to be closer to presentative judgment of human

2. rename the concept to clarify how it really implemented.