lhotari opened a new issue, #23480: URL: https://github.com/apache/pulsar/issues/23480
### Search before asking - [X] I searched in the [issues](https://github.com/apache/pulsar/issues) and found nothing similar. ### Motivation Key_Shared subscriptions don't currently support negative acknowledgements (nack). Consumers can get stuck with Key_Shared subscriptions in all previous versions of Pulsar before 4.0.0. With Pulsar 4.0.0, the consumers will no longer get stuck due to using nacks. This has been addressed with [PIP-379: Key_Shared Draining Hashes for Improved Message Ordering](https://github.com/apache/pulsar/blob/master/pip/pip-379.md) improvements. However, in Pulsar 4.0.0, the nacked messages will get relivered after a delay without considering the ordering. There's a need to also preserve ordering when using nacks in Key_Shared subscriptions. ### Solution Make changes in the Pulsar broker and clients to hold back any further messages for a particular key when negative acknowledgement has been issued for a message. Messages should be held back until the original message gets redelivered. This might require changes in the Pulsar binary protocol. ### Alternatives _No response_ ### Anything else? _No response_ ### Are you willing to submit a PR? - [ ] I'm willing to submit a PR! -- 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: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
