消费者LAG在消费者群体中意味着什么

Question

我发现，当生产者尝试发送消息时，Kafka Consumer始终无法接收消息。当我检查kafka消费者时，看到了LAG值：

 docker run   --net=host   --rm <docker image> kafka-consumer-groups --zookeeper localhost:2181  --describe --group mgmt_testing

GROUP                          TOPIC    PARTITION   CURRENT-OFFSET  LOG-END-OFFSET    LAG             OWNER
mgmt_testing          mgmt_testing         0           44              44              0               mgmt_testing_aws-us-east-1-mr3-10-10-8-218-1561090200381-21858516-0
mgmt_testing          mgmt_testing          1          35              35              0               mgmt_testing_aws-us-east-1-mr3-10-10-8-218-1561090200381-21858516-0
mgmt_testing          mgmt_testing          2          39              39              0               mgmt_testing_aws-us-east-1-mr3-10-10-8-218-1561090200381-21858516-0
mgmt_testing          mgmt_testing          3          37              37              0               mgmt_testing_aws-us-east-1-mr3-10-10-8-218-1561090200381-21858516-0
mgmt_testing          mgmt_testing          4          25              38              13              mgmt_testing_aws-us-east-1-mr3-10-10-8-218-1561090200381-21858516-0
mgmt_testing          mgmt_testing          5          458             666             208             mgmt_testing_aws-us-east-1-mr3-10-10-8-218-1561090200381-21858516-0
mgmt_testing          mgmt_testing          6          808167          808181          14              mgmt_testing_aws-us-east-1-mr3-10-10-8-218-1561090200381-21858516-0
mgmt_testing          mgmt_testing          7          434028          434041          13              mgmt_testing_aws-us-east-1-mr3-10-10-8-218-1561090200381-21858516-0

LAG在这里是什么意思？难道这就是消费者无法接收消息的原因吗？

Answer 1

从本质上讲，滞后是在向Kafka代理发布消息与使用消息之间始终会有一些延迟的事实。 sematext的网站上有一个很好的描述：https://sematext.com/blog/kafka-consumer-lag-offsets-monitoring/