[GitHub] [pulsar] Shawyeok commented on issue #15445: CPU usage 100% when use Key_Shared

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

Shawyeok commented on issue #15445:
URL: https://github.com/apache/pulsar/issues/15445#issuecomment-1118334156

   > When use Key_Shared, if one consumer consume slowly and others are normal, MessageRedeliveryController#messagesToRedeliver will keep growing and could be very large.
   
   Additional context:
   The slow consumer will ends with zero availablePermits, and message positions will be recorded in `MessageRedeliveryController#messagesToRedeliver`, when none of the whole batch of messages sent to consumer, `isDispatcherStuckOnReplays` will be marked.
   https://github.com/apache/pulsar/blob/2b2e0c50183c71e954f5c6e8bfcd7e36130279a5/pulsar-broker/src/main/java/org/apache/pulsar/broker/service/persistent/PersistentStickyKeyDispatcherMultipleConsumers.java#L310-L330
   
   Next time call `getMessagesToReplayNow` in readMoreEntries, it'll returns empty, then it'll read next batch of messages by cursor, therefor more message positions will be recorded.
   https://github.com/apache/pulsar/blob/2b2e0c50183c71e954f5c6e8bfcd7e36130279a5/pulsar-broker/src/main/java/org/apache/pulsar/broker/service/persistent/PersistentStickyKeyDispatcherMultipleConsumers.java#L436-L446
   https://github.com/apache/pulsar/blob/2b2e0c50183c71e954f5c6e8bfcd7e36130279a5/pulsar-broker/src/main/java/org/apache/pulsar/broker/service/persistent/PersistentStickyKeyDispatcherMultipleConsumers.java#L310-L330


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