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Posted to commits@rocketmq.apache.org by aa...@apache.org on 2022/06/22 15:25:11 UTC
[rocketmq-clients] branch master updated: Docs: add docs about new message id (WiP) (#13)
This is an automated email from the ASF dual-hosted git repository.
aaronai pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/rocketmq-clients.git
The following commit(s) were added to refs/heads/master by this push:
new e58986d Docs: add docs about new message id (WiP) (#13)
e58986d is described below
commit e58986dc0112c1f1ead21c44847f87eafca9cae4
Author: Aaron Ai <ya...@gmail.com>
AuthorDate: Wed Jun 22 23:25:06 2022 +0800
Docs: add docs about new message id (WiP) (#13)
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docs/design.md | 3 +++
docs/message_id.md | 21 +++++++++++++++++++++
docs/observability.md | 0
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+# Design of RocketMQ clients
+
+As we know in
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+# Message Identifier
+
+Here is the new design for message identifier.
+
+## Background
+In the past, there are two types of implementation of message identifier.
+
+1. Message identifier based on the broker address and the offset in message queue, find in [MessageDecoder#createMessageId](https://github.com/apache/rocketmq/blob/release-4.9.3/common/src/main/java/org/apache/rocketmq/common/message/MessageDecoder.java#L62-L71)
+2. Message identifier based on the client IP and unix timestamp, find in [MessageClientIDSetter#createUniqID](https://github.com/apache/rocketmq/blob/release-4.9.3/common/src/main/java/org/apache/rocketmq/common/message/MessageClientIDSetter.java#L114-131)
+
+The first type of message identifier is purely based on server-side information, which makes each message stored on the broker absolutely unique. The second message identifier is purely based on client information.
+
+Both the two types of message identifier have their own shortcomings in the new context.
+
+For the first type, the new message identifier is not expected to be bound to the persistent information. Considering this scenario: a failure to send message triggers automatic retry, resulting in duplicate message. Since the two messages are exactly the same for client, they should have the same message identifier.
+
+As for the second type, the imperfect algorithm design is the greatest flaw. Specifically, when the client runs for more than a month, the probability of message id repetition will be greatly increased.
+
+## Detailed Design
+
+
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