BUG ： Consumers start slowly #3434
Description
It takes a long time for consumers to start to consume. max waiting time is ClientConfig#heartbeatBrokerInterval = 1000*30
(30s).
and in broker broker.log,you will find :
2021-10-27 11:29:03 WARN PullMessageThread_35 - The broker's subscription is not latest, group: test_order *
2021-10-27 11:29:03 WARN PullMessageThread_49 - The broker's subscription is not latest, group: test_order *
2021-10-27 11:29:03 WARN PullMessageThread_62 - The broker's subscription is not latest, group: test_order *
2021-10-27 11:29:03 WARN PullMessageThread_75 - The broker's subscription is not latest, group: test_order *
2021-10-27 11:29:04 WARN PullMessageThread_33 - The broker's subscription is not latest, group: test_order *
2021-10-27 11:29:04 WARN PullMessageThread_44 - The broker's subscription is not latest, group: test_order *
2021-10-27 11:29:04 WARN PullMessageThread_55 - The broker's subscription is not latest, group: test_order *
2021-10-27 11:29:04 WARN PullMessageThread_106 - The broker's subscription is not latest, group: test_order *
2021-10-27 11:29:04 WARN PullMessageThread_102 - The broker's subscription is not latest, group: test_order *
2021-10-27 11:29:05 WARN PullMessageThread_37 - The broker's subscription is not latest, group: test_order *
2021-10-27 11:29:05 WARN PullMessageThread_109 - The broker's subscription is not latest, group: test_order *
2021-10-27 11:29:05 WARN PullMessageThread_1 - The broker's subscription is not latest, group: test_order *
2021-10-27 11:29:05 WARN PullMessageThread_4 - The broker's subscription is not latest, group: test_order *
原因：
broker 中会比较 subscription 的版本号，这个版本号由客户端心跳上报。理论broker 的版本号和客户端是一致的。
在进行rebalance 时，如果rebalance 发生了变化（第一次启动会触发），就会更新本地的版本号，然后主动更新到broker。
RebalancePushImpl#83
// notify broker
this.getmQClientFactory().sendHeartbeatToAllBrokerWithLock();
理论上这样 客户端和broker 的版本号还是一样的。
但是在实际情况中，rebalance 完成后这时有可能心跳定时任务也在进行，这会导致获取 lockHeartbeat 锁失败。无法发送心跳。此时 broker 的版本号会小于客户端版本号。直到 下次心跳定时任务后，broker 版本号和本地一致，才能开始正常消费。