com.alibaba.rocketmq.client.exception.MQClientException: Send [1] times, still failed, cost [696094]ms, Topic: TopicTest, BrokersSent: [broker-b, null]See https://github.com/alibaba/RocketMQ/issues/50 for further details.    at com.alibaba.rocketmq.client.impl.producer.DefaultMQProducerImpl.sendDefaultImpl(DefaultMQProducerImpl.java:578)    at com.alibaba.rocketmq.client.impl.producer.DefaultMQProducerImpl.send(DefaultMQProducerImpl.java:1031)    at com.alibaba.rocketmq.client.impl.producer.DefaultMQProducerImpl.send(DefaultMQProducerImpl.java:1025)    at com.alibaba.rocketmq.client.producer.DefaultMQProducer.send(DefaultMQProducer.java:95)

 

关键代码片段

final long maxTimeout = this.defaultMQProducer.getSendMsgTimeout() + 1000;        final long beginTimestamp = System.currentTimeMillis();        long endTimestamp = beginTimestamp;        TopicPublishInfo topicPublishInfo = this.tryToFindTopicPublishInfo(msg.getTopic());        if (topicPublishInfo != null && topicPublishInfo.ok()) {            MessageQueue mq = null;            Exception exception = null;            SendResult sendResult = null;            int timesTotal = 1 + this.defaultMQProducer.getRetryTimesWhenSendFailed();            int times = 0;            String[] brokersSent = new String[timesTotal];            for (; times < timesTotal && (endTimestamp - beginTimestamp) < maxTimeout; times++) {                String lastBrokerName = null == mq ? null : mq.getBrokerName();                MessageQueue tmpmq = topicPublishInfo.selectOneMessageQueue(lastBrokerName);                if (tmpmq != null) {                    mq = tmpmq;                    brokersSent[times] = mq.getBrokerName();                    try {                        sendResult = this.sendKernelImpl(msg, mq, communicationMode, sendCallback, timeout);                        endTimestamp = System.currentTimeMillis();                        switch (communicationMode) {                        case ASYNC:                            return null;                        case ONEWAY:                            return null;                        case SYNC:                            if (sendResult.getSendStatus() != SendStatus.SEND_OK) {                                if (this.defaultMQProducer.isRetryAnotherBrokerWhenNotStoreOK()) {                                    continue;                                }                            }                            return sendResult;                        default:                            break;                        }                    }                    catch  ... //省略部分代码                }                else {                    break;                }            } // end of for            if (sendResult != null) {                return sendResult;            }            String info =                    String.format("Send [%d] times, still failed, cost [%d]ms, Topic: %s, BrokersSent: %s", //                        times, //                        (System.currentTimeMillis() - beginTimestamp), //                        msg.getTopic(),//                        Arrays.toString(brokersSent));            info += FAQUrl.suggestTodo(FAQUrl.SEND_MSG_FAILED);            throw new MQClientException(info, exception);        }

 

1. 循环几次发送几次

2. selectOneMessageQueue 返回与上一个broker不同名的broker

3. timesTotal  是brokersSent 数组

4. 某broker发送失败时，如果想要重试其他broker，需要把retryAnotherBrokerWhenNotStoreOK设置为true(默认为false)

5. 最大超时时间是在超时时间基础上增加1s（坑？）