[GitHub] [pulsar] codelipenghui commented on a change in pull request #10920: [broker] Fix issue where Key_Shared consumers could get stuck

[GitBox <gi...@apache.org>]

codelipenghui commented on a change in pull request #10920:
URL: https://github.com/apache/pulsar/pull/10920#discussion_r651021560



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File path: pulsar-broker/src/main/java/org/apache/pulsar/broker/service/persistent/PersistentStickyKeyDispatcherMultipleConsumers.java
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@@ -121,8 +121,14 @@ public synchronized void addConsumer(Consumer consumer) throws BrokerServiceExce
 
     @Override
     public synchronized void removeConsumer(Consumer consumer) throws BrokerServiceException {
-        super.removeConsumer(consumer);
+        // The consumer must be removed from the selector before calling the superclass removeConsumer method.
+        // In the superclass removeConsumer method, the pending acks that the consumer has are added to
+        // messagesToRedeliver. If the consumer has not been removed from the selector at this point,

Review comment:
       > If the consumer has not been removed from the selector at this point
   
   Looks like a race condition between sending messages to the consumer and remove the consumer from the selector?
   
   We have a `synchronized` to protect the `readEntriesComplete` and `removeConsumer`. How can this happen?




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