[GitHub] [rocketmq] yglovewms commented on pull request #3074: [ISSUES #3076] add the Dynamic flow control of Default DefaultMQPushConsumer,and give a sample

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yglovewms commented on pull request #3074:
URL: https://github.com/apache/rocketmq/pull/3074#issuecomment-868119157


   > 利用tcp滑动窗口的原理，为批量消费提供了一个动态窗口，可以根据阈值以及上下限，实时调整DefaultMQPushConsumer到broker拉取数据的间隔时间，根据与阈值比较每次加或减固定的步长，并为之提供了使用例子。
   > 
   > 如图：
   > ![SE77%D@L4K@JE(3}}98@M(U](https://user-images.githubusercontent.com/52808040/123279860-d8613200-d53a-11eb-88f5-5cee04ded1b7.png)
   > 允许堆积的最大值为2000，并设定其它参数。
   > ![M}CUX8Y_(M) H3P~X9KTNYM](https://user-images.githubusercontent.com/52808040/123279878-dc8d4f80-d53a-11eb-901f-d1a50875b4c7.png)
   > 每次有消息push到客户端，会判断是否到了用户设置的检验间隔时间，如果是，则采集数据动态调整拉取间隔。当堆积数量超过阈值，每次缩短拉取时间。
   > ![56AMTK%JSE2% 1R~~R@1%RJ](https://user-images.githubusercontent.com/52808040/123279897-e0b96d00-d53a-11eb-8402-a7285e00aec5.png)
   > 如果少于阈值，则增加。
   > 如果没有消息到达，则不做处理不影响拉取间隔。
   > 
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