[GitHub] suclogger commented on issue #296: Not found the consumer group consume stats, because return offset table is empty, maybe the consumer not consume any message

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suclogger commented on issue #296: Not found the consumer group consume stats, because return offset table is empty, maybe the consumer not consume any message
URL: https://github.com/apache/rocketmq/issues/296#issuecomment-384214293
 
 
   I've been encountering the same problem while try to trace consume status of broadcast messages.
   As is shown in the source code `DefaultMQPushConsumerImpl`:
   
   ```java
   ...
   if (MessageModel.CLUSTERING == this.defaultMQPushConsumer.getMessageModel()) {
               commitOffsetValue = this.offsetStore.readOffset(pullRequest.getMessageQueue(), ReadOffsetType.READ_FROM_MEMORY);
               if (commitOffsetValue > 0) {
                   commitOffsetEnable = true;
               }
           }
   ...
           int sysFlag = PullSysFlag.buildSysFlag(
               commitOffsetEnable, // commitOffset
               true, // suspend
               subExpression != null, // subscription
               classFilter // class filter
           );
   ...
   ```
   When consumeMode is set to broadcast, commit log is not recorded and so not submit to the broker, so if you can't find consume status afterward.
   
   I assume that this is a design failure.
   
   Originally offset is recorded by consumer-group in broker, but under broadcast mode, every client within the same consumer-group has it's own offset. And that makes it impossible to record consume status for broadcast message.
   
   Would @vongosling explain the design and if it is planed to be fixed?
   

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