[GitHub] [pulsar] aloyszhang opened a new issue #11825: Consumer may receive duplicated message after seek if AcknowledgmentAtBatchIndexLevelEnabled

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

aloyszhang opened a new issue #11825:
URL: https://github.com/apache/pulsar/issues/11825


   **Describe the bug**
   If AcknowledgmentAtBatchIndexLevelEnabled, consumer may receive duplicated messages after seek to batchIndex.
   
   **To Reproduce**
   Steps to reproduce the behavior:
   1. Create producer and enable batch
   2. send some message and pick one BatchMessageId 
   3. create consumer and seek to the BatchMessageId
   4. consumer may receive duplicated messages whose MessageId is  less than BatchMessageId
   
   **Expected behavior**
   Seek at batchIndex should be take effect.
   
   **Additional context**
   Consumer sends a seek request at BatchMessageId, broker processes this request in two step:
   1. disconnect the current consumer, broker sends CommandCloseConsumer response to consumer
   2. resets cursor and sends CommandSuccess response
   
   
   For consumer:
   1. On CommandCloseConsumer, consumer closes the connection and will try re-connect after a backoff time(default is 100ms). After re-connected, consumer will `clearReceiverQueue` and get the `startMessageId` which is used for filter out the messages before the seeked messageId.
   ```java
    if (duringSeek.compareAndSet(true, false)) {
               return seekMessageId;
           } else if (subscriptionMode == SubscriptionMode.Durable) {
               return startMessageId;
           }
   ```
   
   2. On CommandSuccess，  consumer will set the `seekMessageId` to the seek messageId and `duringSeek` to true.
   
   If re-connect happends before consumer receives CommandSuccess, then `startMessageId` will be not updated by `seekMessageId`, which will cause message duplication.
   
   


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[GitHub] [pulsar] codelipenghui closed issue #11825: Consumer may receive duplicated message after seek if AcknowledgmentAtBatchIndexLevelEnabled

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

codelipenghui closed issue #11825:
URL: https://github.com/apache/pulsar/issues/11825


   


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