问题描述
根据“将 Apache Kafka MirrorMaker 与事件中心配合使用”一文，成功配置了Mirror Maker来发送数据到Event Hub中。为什么只能成功运行一会(10分钟 ~ 2小时左右）就会出现Timeout Exception，然后Kafka MirrorMaker就会中断退出呢？
异常消息为：
[2022-05-25 14:29:21,683] INFO [Producer clientId=mirror_maker_producer] Proceeding to force close the producer since pending requests could not be completed within timeout 0 ms.
(org.apache.kafka.clients.producer.KafkaProducer)
[2022-05-25 14:29:21,683] DEBUG [Producer clientId=mirror_maker_producer] Kafka producer has been closed (org.apache.kafka.clients.producer.KafkaProducer)
[2022-05-25 14:29:21,683] ERROR Error when sending message to topic xxxxxxxxxxxx with key: 16 bytes, value: 875 bytes with error:
(org.apache.kafka.clients.producer.internals.ErrorLoggingCallback)
org.apache.kafka.common.errors.TimeoutException: Expiring 18 record(s) for xxxxxxxxxxxx-4: 79823 ms has passed since last append
[2022-05-25 14:29:21,683] INFO Closing producer due to send failure. (kafka.tools.MirrorMaker$)
[2022-05-25 14:29:21,683] INFO [Producer clientId=mirror_maker_producer] Closing the Kafka producer with timeoutMillis = 0 ms. (org.apache.kafka.clients.producer.KafkaProducer)
[2022-05-25 14:29:21,683] INFO [Producer clientId=mirror_maker_producer] Proceeding to force close the producer since pending requests could not be completed within timeout 0 ms.
(org.apache.kafka.clients.producer.KafkaProducer)
[2022-05-25 14:29:21,683] DEBUG [Producer clientId=mirror_maker_producer] Kafka producer has been closed (org.apache.kafka.clients.producer.KafkaProducer)
[2022-05-25 14:29:21,683] ERROR Error when sending message to topic xxxxxxxxxxxx with key: 16 bytes, value: 875 bytes with error:
(org.apache.kafka.clients.producer.internals.ErrorLoggingCallback)
org.apache.kafka.common.errors.TimeoutException: Expiring 18 record(s) for xxxxxxxxxxxx-4: 79823 ms has passed since last append
[2022-05-25 14:29:21,683] INFO Closing producer due to send failure. (kafka.tools.MirrorMaker$)
[2022-05-25 14:29:21,683] INFO [Producer clientId=mirror_maker_producer] Closing the Kafka producer with timeoutMillis = 0 ms. (org.apache.kafka.clients.producer.KafkaProducer)
问题解析
根据错误消息 " Expiring 18 record(s) for xxxxxxxxxxxx-4: 79823 ms has passed since last append " 在网上进行搜索，对发生问题的解释有：
1) Stack Overflow上的解释：https://stackoverflow.com/questions/56807188/how-to-fix-kafka-common-errors-timeoutexception-expiring-1-records-xxx-ms-has
The error indicates that some records are put into the queue at a faster rate than they can be sent from the client.
错误表示Mirror Maker中消息进入Queue中的速度快于从当前客户端发送到服务端的速度（服务端是 Event Hub)
When your Producer sends messages, they are stored in buffer (before sending them to the target broker) and the records are grouped together into batches in order to increase throughput. When a new record is added to the batch, it must be sent within a -configurable- time window which is controlled by
request.timeout.ms(the default is set to 30 seconds). If the batch is in the queue for longer time, aTimeoutExceptionis thrown and the batch records will then be removed from the queue and won't be delivered to the broker.当Mirror Maker(生产者)发送消息时，它们被存储在缓冲区中（在将它们发送到目标代理之前），并且记录被分组到一起以增加吞吐量。 将新记录添加到批次时，它必须在由 request.timeout.ms 控制的时间窗口内发送（默认设置为 30 秒）。 如果批处理在队列中的时间较长，则会引发 TimeoutException，然后批处理记录将从队列中删除并且不会传递给代理。
Increasing the value of
request.timeout.msshould do the trick for you.增加 request.timeout.ms 的值应该可以解决问题。
2) 博客园解释：https://blog.csdn.net/weixin_43432984/article/details/109180842
当每一批消息满了（batch.size）且 requestTimeoutMs < (now - this.lastAppendTime)) 这一批消息就会被标记为过期且不会放到 RecordAccumulator 中（不会再次重试发送）
调大batch.size 参数和request.timeout.ms 参数可解决问题
3) 为什么一出现异常就马上停止运行呢？
因为Mirror Maker的配置参数，abort.on.send.failure 默认为true，决定生产者写入失败时的处理机制就是Abort，终止发送。
从 maybeExpire 函数的源码中发现异常消息产生的根源：
所以根据以上的信息，只需要修改 batch.size 和 request.timeout.ms 参数即可。
**修改前：**
request.timeout.ms = 60000
batch.size = 16384
**修改后：**
request.timeout.ms=180000
batch.size=50000
使用修改后的参数运行Mirror Maker，发送数据到Azure Event Hub正常，连续运行2天没见Timeout 异常。问题解决！
参考资料
记一次Kafka Producer TimeoutException排查：https://blog.csdn.net/weixin_43432984/article/details/109180842
How to fix kafka.common.errors.TimeoutException: Expiring 1 record(s) xxx ms has passed since batch creation plus linger time：https://stackoverflow.com/questions/56807188/how-to-fix-kafka-common-errors-timeoutexception-expiring-1-records-xxx-ms-has
将 Apache Kafka MirrorMaker 与事件中心配合使用：https://docs.azure.cn/zh-cn/event-hubs/event-hubs-kafka-mirror-maker-tutorial
kafka-mirror-maker.sh脚本: https://blog.csdn.net/qq_41154944/article/details/108282641
当在复杂的环境中面临问题，格物之道需：浊而静之徐清，安以动之徐生。 云中，恰是如此!
分类: 【Azure 事件中心】
标签: Azure Developer, 事件中心 Azure Event Hub, Kafka Mirror Maker, Expiring 18 record(s) for, xxxxxxx: 79823 ms has passed since last append, Timeout Exception:
