mq消息消费，broker选址

PullRequest.MessageQueue.BrokerName

根据PullRequest.MessageQueue得到brokerId，默认0或者用缓存中的suggest，每次消息拉取后会更新sugestBrokerId到缓存,

BorkerName+brokerId在缓存（brokerAddrTable）中找到broker的地址

PullRequest在每20s的重平衡加入，MessageQueue是从NameServer取得的topic的订阅信息中拿到

消息发送：

1.TopicPublishInfo.MessageQueue

2.MessageQueue.brokerName

3.private final ConcurrentMap<String/* Broker Name */, HashMap<Long/* brokerId */, String/* address */>> brokerAddrTable =

new ConcurrentHashMap<String, HashMap<Long, String>>();

brokerAddrTable.get(brokerName).get(0)

 

看下发送时如何负载均衡的，可以看到如果发生重试（lastBrokerName 不为null）优先选上次失败的brokerName。否则逐个轮询