January 2018
Beginner to intermediate
234 pages
7h 8m
Chinese
Content preview from Kafka权威指南
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.
Kafka
消费者——从
Kafka
读取数据
｜
61
重试异步提交
我们可以使用一个单调递增的序列号来维护异步提交的顺序。在每次提交偏
移量之后或在回调里提交偏移量时递增序列号。在进行重试前，先检查回调
的序列号和即将提交的偏移量是否相等，如果相等，说明没有新的提交，那
么可以安全地进行重试。如果序列号比较大，说明有一个新的提交已经发送
出去了，应该停止重试。
4.6.4
同步和异步组合提交
一般情况下，针对偶尔出现的提交失败，不进行重试不会有太大问题，因为如果提交失败
是因为临时问题导致的，那么后续的提交总会有成功的。但如果这是发生在关闭消费者或
再均衡前的最后一次提交，就要确保能够提交成功。
因此，在消费者关闭前一般会组合使用
commitAsync()
和
commitSync()
。它们的工作原理
如下（后面讲到再均衡监听器时，我们会讨论如何在发生再均衡前提交偏移量）
:
try {
while (true) {
ConsumerRecords<String, String> records = consumer.poll(100);
for (ConsumerRecord<String, String> record : records) {
System.out.println("topic = %s, partition = %s, offset = %d,
customer = %s, country = %s\n",
record.topic(), record.partition(), ...
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
and much more.
Read now
Unlock full access
More than 5,000 organizations count on O’Reilly
O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.