apache-kafka - 卡夫卡排序保证

Question

我正在浏览 kafka 文档并遇到了

Guarantees

At a high-level, Kafka gives the following guarantees:

Messages sent by a producer to a particular topic partition will be appended in the order they are sent. That is, if a record M1 is sent by the same producer as a record M2, and M1 is sent first, then M1 will have a lower offset than M2 and appear earlier in the log. A consumer instance sees records in the order they are stored in the log. For a topic with replication factor N, we will tolerate up to N-1 server failures without losing any records committed to the log.

我有几个问题。

是否总是保证 M1 的偏移量低于 M2 ？如果 M1 晚于 M2 重试怎么办？

我从各种文档中也了解到，订购是没有保障的，消费者必须自己处理。

Answer 1

即使只有一个分区，一种可能的情况是:

制作人发送 M1

制作人发送 M2

M1由于某些失败，在第一次尝试时没有被确认

M2已发货

M1在随后的尝试中交付。

避免这种情况的一种简单方法是通过生产者配置 max.in.flight.requests.per.connection=1 .

这当然会影响性能，因此应谨慎使用。