TGIP_CN_025：Apache Pulsar 问答专场

1 .TGIP-CN 025 Pulsar Q&A Penghui Li & Xiaolong Ran 

2 .Features and bug fixes A. Add ability to specify the subscription init position for functions #789 B. Fix IndexOutOfBoundsException in the Key_Shared subscription when dispatch batch message to consumers #802 C. Support set max consumers per subscription on the topic level #800 D. Support set max consumers on the topic level #796 E. Support set message key in pulsar-perf #798 F. Support key based message batching in the CPP Client #799 G. Transaction message ack abort on subscriptions #7979 4 9 8 6 3 1 

3 .Data deletion in Pulsar Topic Ledger - 2 (open) Ledger - 1 (closed) Ledger - 0 (closed) Fragment F - 1 F - 0 Fragment E-3 E-2 E-1 E-0 E-3 E-2 E-1 E-0 E-3 E-2 E-1 E-0 

4 .Data deletion in Pulsar Current active in the topic Removed from the topic Ledger - 2 (open) LedgerTopic - 1 (closed) Ledger - 0 (closed) Not removed from the topic 

5 .Data deletion in Pulsar 

6 .Data deletion in Pulsar 

7 .Data deletion in Pulsar L-0 E-0 L-1 E-0 L-2 E-0 L-0 E-0 L-0 E-0 L-1 E-0 L-1 E-1 Checkpoint L-1 E-0 L-1 E-1 L-1 E-2 L-1 E-1 L-2 E-0 L-0 E-1 L-2 E-0 Journal Entry Log - 0 Index DB Entry Log - 1 

8 .Data deletion in Pulsar minorCompactionThreshold=0. majorCompactionThreshold=0. minorCompactionInterval=360 majorCompactionInterval=86400 0 5 2 

9 .Question 1 最近刚刚接触pulsar项⽬，之前⼀直关注confluence的kafka项⽬，对pulsar很感兴趣。⽤ pulsar对数据做永久保存怎么样，是否是个好主意？我看到对接presto时候是直接去bookie⾥⾯ 取历史数据，那么当做批处理的存储层也可以吧，会对broker的消息吞吐产⽣影响么？ 

10 .Question 2 最请问有没有pulsar性能压测的指导，不知道咋测试pulsar的性能，求⼤佬指导指导，谢谢！ https://github.com/apache/pulsar/tree/master/pulsar-testclient https://github.com/openmessaging/openmessaging-benchmark 

11 .Question 3 通过bookkeeper shell metaformat 操作后，是不是整个bookie集群的元数据都格式化了？ ⽽不是单个bookie节点。然后broker消费不了数据（⽣产没问题），异常ERROR org.apache.pulsar.broker.service.persistent.PersistentDispatcherMultipleC onsumers - [persistent://public/default/topic_aep_order / aep_order_consumer_group] Error reading entries at 110260:190 : No such ledger exists, Read Type Normal - Retrying to read in 55.281 seconds。请问 这种情况怎么快速恢复？topic⽐较多 

12 .Question 4 Pulsar 如何保证 Bookie 节点的负载均衡呢 ⽐如原来有三个 Bookie 节点, 现新加了⼀个 bookie节点, 在写⼊数据时会提⾼新加 Bookie 节点的选中率来实现均衡吗 

13 .Question 5 要验证pulsar⽀持百万级topic数量，请问各位有什么建议吗？需要多少个租户/名称空间？创建 百万topic后，如何判断集群的稳定性？ 

14 .Question 6 ⼤家有尝试过在function中动态创建topic，并根据不同参数指定不同分区数的经验么？除了⽤ pulsar-admin，还有其他便利的⽅式么？现在在function中有啥姿势可以尝试？之前我再 issue上提了，但回复是⽤pulsar-admin接⼝。觉得有点重，不知道有没有更便捷的⽅式？ 

15 .Question 7 请问下，新增了⼏个functionWorker 节点，怎么让任务做⼀次 rebalance ？ https://github.com/apache/pulsar/pull/7388 https://github.com/apache/pulsar/pull/7449 

16 .扫码⼊群！ Pulsar 中国社区等你加⼊ 添加好友后，回复“进群”即可 

17 .Thanks