[GitHub] [rocketmq-externals] ferrirW commented on issue #66: rocketmq-cpp/producer/tryToCompressMessage没有判断msg是否被压缩过

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ferrirW commented on issue #66:
URL: https://github.com/apache/rocketmq-externals/issues/66#issuecomment-1105247718

   > 看了下bugfix的代码[apache/rocketmq#294](https://github.com/apache/rocketmq/pull/294)，不太理解DefaultMQProducerImpl.sendKernelImpl在异步发送逻辑单独resetbody的原因，在大的try,catch,finally中不是已经resetbody，在异步发送的callback回调里再次使用改msg，应该不会是压缩后的吧
   
   https://github.com/apache/rocketmq/pull/294 解决的问题恰好与 @kelly6 的问题相反
   
   异步发送时 finally 重新赋值的时机并不确定，有很大概率是在第一次发送结束前就完成了 finally 中的赋值，因此在内部重试前 msg.body 大概率已经被重新赋值过，而 onExceptionImpl 中的重试逻辑 MQClientAPIImpl.sendMessageAsync 不会再对数据进行压缩，简言之，在异步发送的情况下，如果调用 onExceptionImpl 内部的重试，有很大概率发送的是无压缩的数据
   
   注释也阐明了这一点
   //If msg body was compressed, msgbody should be reset using prevBody.
   //Clone new message using commpressed message body and recover origin massage.
   
   
   
   
   
   
   
   


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