Send [1] times, still failed

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？）