fransguelinckx opened a new issue #9940: URL: https://github.com/apache/pulsar/issues/9940
**Describe the bug** Messages can get consumed out of order with key_shared subscriptions and small receiverQueueSize **To Reproduce** Steps to reproduce the behavior: * A producer that produces a relatively high load of messages with different keys. Crucial to have related messages with the same message key in a specific order. * Partitioned topic on which the messages are produced. * A lot of key_shared subscriptions on the topic and several consumers within every single subscription. * Consumption of messages is synchronous and also should take some time. * Consumers have a receiverQueueSize of 1. **Expected behavior** I expect messages with the same key to be processed in the correct order by the same consumer. **Additional context** This issue was already discussed on [Slack](https://apache-pulsar.slack.com/archives/C5Z4T36F7/p1615199642267000) and @codelipenghui asked me to create this issue to track the problem. ---------------------------------------------------------------- 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. For queries about this service, please contact Infrastructure at: [email protected]
