[I] [Bug] Fix Lite topic ack re-dispatching the event while holding the pop lock [rocketmq]

["f1amingo (via GitHub)" <gi...@apache.org>]

f1amingo opened a new issue, #11250:
URL: https://github.com/apache/rocketmq/issues/11250

   ### Before Creating the Bug Report
   
   - [x] I found a bug, not just asking a question.
   - [x] I have searched the GitHub Issues and Discussions and believe this is not a duplicate.
   - [x] I have confirmed this bug belongs to the current repository.
   
   ### Runtime platform environment
   
   OS: macOS / Linux
   
   ### RocketMQ version
   
   branch: develop
   
   ### JDK Version
   
   Oracle JDK 8
   
   ### Describe the Bug
   
   When a lite message is acked, the broker re-dispatches the lite topic to the consumer while still holding the pop lock of that lite topic. A pop that takes this event during that window cannot acquire the lock, so it skips the lite topic, and the event is already consumed and not re-queued. If no other notification comes for that lite topic, its remaining messages are not delivered.
   
   ### Steps to Reproduce
   
   1. A consumer pops a lite topic with several messages in FIFO order.
   2. The consumer acks the first message; the ack commits the offset and re-dispatches the lite topic while holding the pop lock.
   3. A pop running concurrently takes the re-dispatched event before the ack releases the lock, fails to acquire the lock and skips the lite topic.
   
   ### What Did You Expect to See?
   
   A pop triggered by the ack's re-dispatch can read the lite topic, and the remaining messages are delivered.
   
   ### What Did You See Instead?
   
   The re-dispatch happens while the lock is still held, so the triggered pop may fail to acquire the lock and the event is dropped.
   
   ### Additional Context
   
   Found by code review while investigating #11248. The dispatch decision needs the lock, but the dispatch itself does not.
   


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Re: [I] [Bug] Fix Lite topic ack re-dispatching the event while holding the pop lock [rocketmq]

["RongtongJin (via GitHub)" <gi...@apache.org>]

RongtongJin closed issue #11250: [Bug] Fix Lite topic ack re-dispatching the event while holding the pop lock
URL: https://github.com/apache/rocketmq/issues/11250


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