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聊聊 RocketMQ 的 Broker 源码

broker 的启动形式有点类似于 NameServer,都是服务类型的,跟 Consumer 差别比较大,

首先是org.apache.rocketmq.broker.BrokerStartup中的 main 函数,org.apache.rocketmq.broker.BrokerStartup#createBrokerController基本就是读取参数,这里差点把最核心的初始化给漏了,

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final BrokerController controller = new BrokerController(
brokerConfig,
nettyServerConfig,
nettyClientConfig,
messageStoreConfig);
// remember all configs to prevent discard
controller.getConfiguration().registerConfig(properties);

boolean initResult = controller.initialize();

前面是以 broker 配置,netty 的服务端和客户端配置,以及消息存储配置在实例化 BrokerController,然后就是初始化了

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public boolean initialize() throws CloneNotSupportedException {
boolean result = this.topicConfigManager.load();

result = result && this.consumerOffsetManager.load();
result = result && this.subscriptionGroupManager.load();
result = result && this.consumerFilterManager.load();

前面这些就是各个配置的 load 了,然后是个我认为比较重要的部分messageStore 的实例化,

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if (result) {
try {
this.messageStore =
new DefaultMessageStore(this.messageStoreConfig, this.brokerStatsManager, this.messageArrivingListener,
this.brokerConfig);
if (messageStoreConfig.isEnableDLegerCommitLog()) {
DLedgerRoleChangeHandler roleChangeHandler = new DLedgerRoleChangeHandler(this, (DefaultMessageStore) messageStore);
((DLedgerCommitLog)((DefaultMessageStore) messageStore).getCommitLog()).getdLedgerServer().getdLedgerLeaderElector().addRoleChangeHandler(roleChangeHandler);
}
this.brokerStats = new BrokerStats((DefaultMessageStore) this.messageStore);
//load plugin
MessageStorePluginContext context = new MessageStorePluginContext(messageStoreConfig, brokerStatsManager, messageArrivingListener, brokerConfig);
this.messageStore = MessageStoreFactory.build(context, this.messageStore);
this.messageStore.getDispatcherList().addFirst(new CommitLogDispatcherCalcBitMap(this.brokerConfig, this.consumerFilterManager));
} catch (IOException e) {
result = false;
log.error("Failed to initialize", e);
}
}

result = result && this.messageStore.load();

先是实例化,实例化构造函数里的代码比较重要,重点看一下

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public DefaultMessageStore(final MessageStoreConfig messageStoreConfig, final BrokerStatsManager brokerStatsManager,
final MessageArrivingListener messageArrivingListener, final BrokerConfig brokerConfig) throws IOException {
this.messageArrivingListener = messageArrivingListener;
this.brokerConfig = brokerConfig;
this.messageStoreConfig = messageStoreConfig;
this.brokerStatsManager = brokerStatsManager;
this.allocateMappedFileService = new AllocateMappedFileService(this);
if (messageStoreConfig.isEnableDLegerCommitLog()) {
this.commitLog = new DLedgerCommitLog(this);
} else {
this.commitLog = new CommitLog(this);
}
this.consumeQueueTable = new ConcurrentHashMap<>(32);

this.flushConsumeQueueService = new FlushConsumeQueueService();
this.cleanCommitLogService = new CleanCommitLogService();
this.cleanConsumeQueueService = new CleanConsumeQueueService();
this.storeStatsService = new StoreStatsService();
this.indexService = new IndexService(this);
if (!messageStoreConfig.isEnableDLegerCommitLog()) {
this.haService = new HAService(this);
} else {
this.haService = null;
}
this.reputMessageService = new ReputMessageService();

this.scheduleMessageService = new ScheduleMessageService(this);

this.transientStorePool = new TransientStorePool(messageStoreConfig);

if (messageStoreConfig.isTransientStorePoolEnable()) {
this.transientStorePool.init();
}

this.allocateMappedFileService.start();

this.indexService.start();

this.dispatcherList = new LinkedList<>();
this.dispatcherList.addLast(new CommitLogDispatcherBuildConsumeQueue());
this.dispatcherList.addLast(new CommitLogDispatcherBuildIndex());

File file = new File(StorePathConfigHelper.getLockFile(messageStoreConfig.getStorePathRootDir()));
MappedFile.ensureDirOK(file.getParent());
lockFile = new RandomAccessFile(file, "rw");
}

这里面有很多类,不过先把从构造函数里传进来的忽略下,接下来就是 AllocateMappedFileService 这个service,前面看过文章的可能会根据上面的代码猜到,这也是个 ServiceThread,如果是对RocketMQ 有所了解的可能从名字可以看出这个类是关于 RocketMQ 消息怎么落盘的,当需要创建MappedFile时(在MapedFileQueue.getLastMapedFile方法中),向该线程的requestQueue队列中放入AllocateRequest请求对象,该线程会在后台监听该队列,并在后台创建MapedFile对象,即同时创建了物理文件。然后是创建了 IndexService 服务线程,用来给创建索引;还有是FlushConsumeQueueService是将ConsumeQueue 刷入磁盘;CleanCommitLogService用来清理过期的 CommitLog,默认是 72 小时以上;CleanConsumeQueueService是将小于最新的 CommitLog 偏移量的 ConsumeQueue 清理掉;StoreStatsService是储存统计服务;HAService用于CommitLog 的主备同步;ScheduleMessageService用于定时消息;还有就是这个ReputMessageService非常重要,就是由它实现了将 CommitLog 以 topic+queue 纬度构建 ConsumeQueue,后面TransientStorePool是异步刷盘时的存储buffer,也可以从后面的判断中看出来

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public boolean isTransientStorePoolEnable() {
return transientStorePoolEnable && FlushDiskType.ASYNC_FLUSH == getFlushDiskType()
&& BrokerRole.SLAVE != getBrokerRole();
}

再然后就是启动两个服务线程,dispatcherList是为CommitLog文件转发请求,差不多这个初始化就这些内容。

然后回到外层,下面是主备切换的配置,然后是数据统计,接着是存储插件加载,然后是往转发器链表里再加一个过滤器

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if (messageStoreConfig.isEnableDLegerCommitLog()) {
DLedgerRoleChangeHandler roleChangeHandler = new DLedgerRoleChangeHandler(this, (DefaultMessageStore) messageStore);
((DLedgerCommitLog)((DefaultMessageStore) messageStore).getCommitLog()).getdLedgerServer().getdLedgerLeaderElector().addRoleChangeHandler(roleChangeHandler);
}
this.brokerStats = new BrokerStats((DefaultMessageStore) this.messageStore);
//load plugin
MessageStorePluginContext context = new MessageStorePluginContext(messageStoreConfig, brokerStatsManager, messageArrivingListener, brokerConfig);
this.messageStore = MessageStoreFactory.build(context, this.messageStore);
this.messageStore.getDispatcherList().addFirst(new CommitLogDispatcherCalcBitMap(this.brokerConfig, this.consumerFilterManager));

接下来就是org.apache.rocketmq.store.MessageStore#load的过程了,

1) 调用ScheduleMessageService.load方法,初始化延迟级别列表。将这些级别(”1s 5s 10s 30s 1m 2m 3m 4m 5m 6m 7m 8m 9m 10m 20m 30m 1h 2h”)的延时存入延迟级别delayLevelTable:ConcurrentHashMap<Integer /* level /, Long/ delay timeMillis */>变量中,例如1s的kv值为1:1000,5s的kv值为2:5000,key值依次类推;每个延迟级别即为一个队列。

2)调用CommitLog.load方法,在此方法中调用MapedFileQueue.load方法,将$HOME /store/commitlog目录下的所有文件加载到MapedFileQueue的List变量中;

3)调用DefaultMessageStore.loadConsumeQueue方法加载consumequeue文件数据到DefaultMessageStore.consumeQueueTable集合中。

初始化StoreCheckPoint对象,加载$HOME/store/checkpoint文件,该文件记录三个字段值,分别是物理队列消息时间戳、逻辑队列消息时间戳、索引队列消息时间戳。

调用IndexService.load方法加载$HOME/store/index目录下的文件。对该目录下的每个文件初始化一个IndexFile对象。然后调用IndexFile对象的load方法将IndexHeader加载到对象的变量中;再根据检查是否存在abort文件,若有存在abort文件,则表示Broker表示上次是异常退出的,则检查checkpoint的indexMsgTimestamp字段值是否小于IndexHeader的endTimestamp值,indexMsgTimestamp值表示最后刷盘的时间,若小于则表示在最后刷盘之后在该文件中还创建了索引,则要删除该Index文件,否则将该IndexFile对象放入indexFileList:ArrayList索引文件集合中。

然后调用org.apache.rocketmq.store.DefaultMessageStore#recover恢复,前面有根据boolean lastExitOK = !this.isTempFileExist();临时文件是否存在来判断上一次是否正常退出,根据这个状态来选择什么恢复策略

接下去是初始化 Netty 服务端,初始化发送消息线程池(sendMessageExecutor)、拉取消息线程池(pullMessageExecutor)、管理Broker线程池(adminBrokerExecutor)、客户端管理线程池(clientManageExecutor),注册事件处理器,包括发送消息事件处理器(SendMessageProcessor)、拉取消息事件处理器、查询消息事件处理器(QueryMessageProcessor,包括客户端的心跳事件、注销事件、获取消费者列表事件、更新更新和查询消费进度consumerOffset)、客户端管理事件处理器(ClientManageProcessor)、结束事务处理器(EndTransactionProcessor)、默认事件处理器(AdminBrokerProcessor),然后是定时任务

BrokerController.this.getBrokerStats().record(); 记录 Broker 状态

BrokerController.this.consumerOffsetManager.persist(); 持久化consumerOffset

BrokerController.this.consumerFilterManager.persist();持久化consumerFilter

BrokerController.this.protectBroker(); 保护 broker,消费慢,不让继续投递

BrokerController.this.printWaterMark(); 打印水位

log.info("dispatch behind commit log {} bytes", BrokerController.this.getMessageStore().dispatchBehindBytes()); 检查落后程度

BrokerController.this.brokerOuterAPI.fetchNameServerAddr(); 定时获取 nameserver

BrokerController.this.printMasterAndSlaveDiff(); 打印主从不一致

然后是 tsl,初始化事务消息,初始化 RPCHook

请把害怕打到公屏上🤦‍♂️,从线程池名字和调用的方法应该可以看出大部分的用途

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this.remotingServer = new NettyRemotingServer(this.nettyServerConfig, this.clientHousekeepingService);
NettyServerConfig fastConfig = (NettyServerConfig) this.nettyServerConfig.clone();
fastConfig.setListenPort(nettyServerConfig.getListenPort() - 2);
this.fastRemotingServer = new NettyRemotingServer(fastConfig, this.clientHousekeepingService);
this.sendMessageExecutor = new BrokerFixedThreadPoolExecutor(
this.brokerConfig.getSendMessageThreadPoolNums(),
this.brokerConfig.getSendMessageThreadPoolNums(),
1000 * 60,
TimeUnit.MILLISECONDS,
this.sendThreadPoolQueue,
new ThreadFactoryImpl("SendMessageThread_"));

this.pullMessageExecutor = new BrokerFixedThreadPoolExecutor(
this.brokerConfig.getPullMessageThreadPoolNums(),
this.brokerConfig.getPullMessageThreadPoolNums(),
1000 * 60,
TimeUnit.MILLISECONDS,
this.pullThreadPoolQueue,
new ThreadFactoryImpl("PullMessageThread_"));

this.replyMessageExecutor = new BrokerFixedThreadPoolExecutor(
this.brokerConfig.getProcessReplyMessageThreadPoolNums(),
this.brokerConfig.getProcessReplyMessageThreadPoolNums(),
1000 * 60,
TimeUnit.MILLISECONDS,
this.replyThreadPoolQueue,
new ThreadFactoryImpl("ProcessReplyMessageThread_"));

this.queryMessageExecutor = new BrokerFixedThreadPoolExecutor(
this.brokerConfig.getQueryMessageThreadPoolNums(),
this.brokerConfig.getQueryMessageThreadPoolNums(),
1000 * 60,
TimeUnit.MILLISECONDS,
this.queryThreadPoolQueue,
new ThreadFactoryImpl("QueryMessageThread_"));

this.adminBrokerExecutor =
Executors.newFixedThreadPool(this.brokerConfig.getAdminBrokerThreadPoolNums(), new ThreadFactoryImpl(
"AdminBrokerThread_"));

this.clientManageExecutor = new ThreadPoolExecutor(
this.brokerConfig.getClientManageThreadPoolNums(),
this.brokerConfig.getClientManageThreadPoolNums(),
1000 * 60,
TimeUnit.MILLISECONDS,
this.clientManagerThreadPoolQueue,
new ThreadFactoryImpl("ClientManageThread_"));

this.heartbeatExecutor = new BrokerFixedThreadPoolExecutor(
this.brokerConfig.getHeartbeatThreadPoolNums(),
this.brokerConfig.getHeartbeatThreadPoolNums(),
1000 * 60,
TimeUnit.MILLISECONDS,
this.heartbeatThreadPoolQueue,
new ThreadFactoryImpl("HeartbeatThread_", true));

this.endTransactionExecutor = new BrokerFixedThreadPoolExecutor(
this.brokerConfig.getEndTransactionThreadPoolNums(),
this.brokerConfig.getEndTransactionThreadPoolNums(),
1000 * 60,
TimeUnit.MILLISECONDS,
this.endTransactionThreadPoolQueue,
new ThreadFactoryImpl("EndTransactionThread_"));

this.consumerManageExecutor =
Executors.newFixedThreadPool(this.brokerConfig.getConsumerManageThreadPoolNums(), new ThreadFactoryImpl(
"ConsumerManageThread_"));

this.registerProcessor();

final long initialDelay = UtilAll.computeNextMorningTimeMillis() - System.currentTimeMillis();
final long period = 1000 * 60 * 60 * 24;
this.scheduledExecutorService.scheduleAtFixedRate(new Runnable() {
@Override
public void run() {
try {
BrokerController.this.getBrokerStats().record();
} catch (Throwable e) {
log.error("schedule record error.", e);
}
}
}, initialDelay, period, TimeUnit.MILLISECONDS);

this.scheduledExecutorService.scheduleAtFixedRate(new Runnable() {
@Override
public void run() {
try {
BrokerController.this.consumerOffsetManager.persist();
} catch (Throwable e) {
log.error("schedule persist consumerOffset error.", e);
}
}
}, 1000 * 10, this.brokerConfig.getFlushConsumerOffsetInterval(), TimeUnit.MILLISECONDS);

this.scheduledExecutorService.scheduleAtFixedRate(new Runnable() {
@Override
public void run() {
try {
BrokerController.this.consumerFilterManager.persist();
} catch (Throwable e) {
log.error("schedule persist consumer filter error.", e);
}
}
}, 1000 * 10, 1000 * 10, TimeUnit.MILLISECONDS);

this.scheduledExecutorService.scheduleAtFixedRate(new Runnable() {
@Override
public void run() {
try {
BrokerController.this.protectBroker();
} catch (Throwable e) {
log.error("protectBroker error.", e);
}
}
}, 3, 3, TimeUnit.MINUTES);

this.scheduledExecutorService.scheduleAtFixedRate(new Runnable() {
@Override
public void run() {
try {
BrokerController.this.printWaterMark();
} catch (Throwable e) {
log.error("printWaterMark error.", e);
}
}
}, 10, 1, TimeUnit.SECONDS);

this.scheduledExecutorService.scheduleAtFixedRate(new Runnable() {

@Override
public void run() {
try {
log.info("dispatch behind commit log {} bytes", BrokerController.this.getMessageStore().dispatchBehindBytes());
} catch (Throwable e) {
log.error("schedule dispatchBehindBytes error.", e);
}
}
}, 1000 * 10, 1000 * 60, TimeUnit.MILLISECONDS);

if (this.brokerConfig.getNamesrvAddr() != null) {
this.brokerOuterAPI.updateNameServerAddressList(this.brokerConfig.getNamesrvAddr());
log.info("Set user specified name server address: {}", this.brokerConfig.getNamesrvAddr());
} else if (this.brokerConfig.isFetchNamesrvAddrByAddressServer()) {
this.scheduledExecutorService.scheduleAtFixedRate(new Runnable() {

@Override
public void run() {
try {
BrokerController.this.brokerOuterAPI.fetchNameServerAddr();
} catch (Throwable e) {
log.error("ScheduledTask fetchNameServerAddr exception", e);
}
}
}, 1000 * 10, 1000 * 60 * 2, TimeUnit.MILLISECONDS);
}

if (!messageStoreConfig.isEnableDLegerCommitLog()) {
if (BrokerRole.SLAVE == this.messageStoreConfig.getBrokerRole()) {
if (this.messageStoreConfig.getHaMasterAddress() != null && this.messageStoreConfig.getHaMasterAddress().length() >= 6) {
this.messageStore.updateHaMasterAddress(this.messageStoreConfig.getHaMasterAddress());
this.updateMasterHAServerAddrPeriodically = false;
} else {
this.updateMasterHAServerAddrPeriodically = true;
}
} else {
this.scheduledExecutorService.scheduleAtFixedRate(new Runnable() {
@Override
public void run() {
try {
BrokerController.this.printMasterAndSlaveDiff();
} catch (Throwable e) {
log.error("schedule printMasterAndSlaveDiff error.", e);
}
}
}, 1000 * 10, 1000 * 60, TimeUnit.MILLISECONDS);
}
}

if (TlsSystemConfig.tlsMode != TlsMode.DISABLED) {
// Register a listener to reload SslContext
try {
fileWatchService = new FileWatchService(
new String[] {
TlsSystemConfig.tlsServerCertPath,
TlsSystemConfig.tlsServerKeyPath,
TlsSystemConfig.tlsServerTrustCertPath
},
new FileWatchService.Listener() {
boolean certChanged, keyChanged = false;

@Override
public void onChanged(String path) {
if (path.equals(TlsSystemConfig.tlsServerTrustCertPath)) {
log.info("The trust certificate changed, reload the ssl context");
reloadServerSslContext();
}
if (path.equals(TlsSystemConfig.tlsServerCertPath)) {
certChanged = true;
}
if (path.equals(TlsSystemConfig.tlsServerKeyPath)) {
keyChanged = true;
}
if (certChanged && keyChanged) {
log.info("The certificate and private key changed, reload the ssl context");
certChanged = keyChanged = false;
reloadServerSslContext();
}
}

private void reloadServerSslContext() {
((NettyRemotingServer) remotingServer).loadSslContext();
((NettyRemotingServer) fastRemotingServer).loadSslContext();
}
});
} catch (Exception e) {
log.warn("FileWatchService created error, can't load the certificate dynamically");
}
}
initialTransaction();
initialAcl();
initialRpcHooks();
}
return result;

Broker 启动过程

贴代码

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public void start() throws Exception {
if (this.messageStore != null) {
this.messageStore.start();
}

if (this.remotingServer != null) {
this.remotingServer.start();
}

if (this.fastRemotingServer != null) {
this.fastRemotingServer.start();
}

if (this.fileWatchService != null) {
this.fileWatchService.start();
}

if (this.brokerOuterAPI != null) {
this.brokerOuterAPI.start();
}

if (this.pullRequestHoldService != null) {
this.pullRequestHoldService.start();
}

if (this.clientHousekeepingService != null) {
this.clientHousekeepingService.start();
}

if (this.filterServerManager != null) {
this.filterServerManager.start();
}

if (!messageStoreConfig.isEnableDLegerCommitLog()) {
startProcessorByHa(messageStoreConfig.getBrokerRole());
handleSlaveSynchronize(messageStoreConfig.getBrokerRole());
this.registerBrokerAll(true, false, true);
}

this.scheduledExecutorService.scheduleAtFixedRate(new Runnable() {

@Override
public void run() {
try {
BrokerController.this.registerBrokerAll(true, false, brokerConfig.isForceRegister());
} catch (Throwable e) {
log.error("registerBrokerAll Exception", e);
}
}
}, 1000 * 10, Math.max(10000, Math.min(brokerConfig.getRegisterNameServerPeriod(), 60000)), TimeUnit.MILLISECONDS);

if (this.brokerStatsManager != null) {
this.brokerStatsManager.start();
}

if (this.brokerFastFailure != null) {
this.brokerFastFailure.start();
}


}

首先是启动messageStore,调用 start 方法,这里面又调用了一些代码

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public void start() throws Exception {

lock = lockFile.getChannel().tryLock(0, 1, false);
if (lock == null || lock.isShared() || !lock.isValid()) {
throw new RuntimeException("Lock failed,MQ already started");
}

lockFile.getChannel().write(ByteBuffer.wrap("lock".getBytes()));
lockFile.getChannel().force(true);
{
/**
* 1. Make sure the fast-forward messages to be truncated during the recovering according to the max physical offset of the commitlog;
* 2. DLedger committedPos may be missing, so the maxPhysicalPosInLogicQueue maybe bigger that maxOffset returned by DLedgerCommitLog, just let it go;
* 3. Calculate the reput offset according to the consume queue;
* 4. Make sure the fall-behind messages to be dispatched before starting the commitlog, especially when the broker role are automatically changed.
*/
long maxPhysicalPosInLogicQueue = commitLog.getMinOffset();
for (ConcurrentMap<Integer, ConsumeQueue> maps : this.consumeQueueTable.values()) {
for (ConsumeQueue logic : maps.values()) {
if (logic.getMaxPhysicOffset() > maxPhysicalPosInLogicQueue) {
maxPhysicalPosInLogicQueue = logic.getMaxPhysicOffset();
}
}
}
if (maxPhysicalPosInLogicQueue < 0) {
maxPhysicalPosInLogicQueue = 0;
}
if (maxPhysicalPosInLogicQueue < this.commitLog.getMinOffset()) {
maxPhysicalPosInLogicQueue = this.commitLog.getMinOffset();
/**
* This happens in following conditions:
* 1. If someone removes all the consumequeue files or the disk get damaged.
* 2. Launch a new broker, and copy the commitlog from other brokers.
*
* All the conditions has the same in common that the maxPhysicalPosInLogicQueue should be 0.
* If the maxPhysicalPosInLogicQueue is gt 0, there maybe something wrong.
*/
log.warn("[TooSmallCqOffset] maxPhysicalPosInLogicQueue={} clMinOffset={}", maxPhysicalPosInLogicQueue, this.commitLog.getMinOffset());
}
log.info("[SetReputOffset] maxPhysicalPosInLogicQueue={} clMinOffset={} clMaxOffset={} clConfirmedOffset={}",
maxPhysicalPosInLogicQueue, this.commitLog.getMinOffset(), this.commitLog.getMaxOffset(), this.commitLog.getConfirmOffset());
this.reputMessageService.setReputFromOffset(maxPhysicalPosInLogicQueue);
this.reputMessageService.start();

/**
* 1. Finish dispatching the messages fall behind, then to start other services.
* 2. DLedger committedPos may be missing, so here just require dispatchBehindBytes <= 0
*/
while (true) {
if (dispatchBehindBytes() <= 0) {
break;
}
Thread.sleep(1000);
log.info("Try to finish doing reput the messages fall behind during the starting, reputOffset={} maxOffset={} behind={}", this.reputMessageService.getReputFromOffset(), this.getMaxPhyOffset(), this.dispatchBehindBytes());
}
this.recoverTopicQueueTable();
}

if (!messageStoreConfig.isEnableDLegerCommitLog()) {
this.haService.start();
this.handleScheduleMessageService(messageStoreConfig.getBrokerRole());
}

this.flushConsumeQueueService.start();
this.commitLog.start();
this.storeStatsService.start();

this.createTempFile();
this.addScheduleTask();
this.shutdown = false;
}

调用DefaultMessageStore.start方法启动DefaultMessageStore对象中的一些服务线程。

  1. 启动ReputMessageService服务线程
  2. 启动FlushConsumeQueueService服务线程;
  3. 调用CommitLog.start方法,启动CommitLog对象中的FlushCommitLogService线程服务,若是同步刷盘(SYNC_FLUSH)则是启动GroupCommitService线程服务;若是异步刷盘(ASYNC_FLUSH)则是启动FlushRealTimeService线程服务;
  4. 启动StoreStatsService线程服务;
  5. 启动定时清理任务

然后是启动ClientHousekeepingService的 netty 服务端和客户端,然后是启动fileWatchService证书服务,接着启动BrokerOuterAPI中的NettyRemotingClient,即建立与NameServer的链接,用于自身Broker与其他模块的RPC功能调用;包括获取NameServer的地址、注册Broker、注销Broker、获取Topic配置、获取消息进度信息、获取订阅关系等RPC功能,然后是PullRequestHoldService服务线程,这个就是实现长轮询的,然后启动管家ClientHousekeepingService服务,负责扫描不活跃的生产者,消费者和 filter,启动FilterServerManager 过滤器服务管理,然后启动定时任务调用org.apache.rocketmq.broker.BrokerController#registerBrokerAll向所有 nameserver 注册 broker,最后是按需开启org.apache.rocketmq.store.stats.BrokerStatsManager和org.apache.rocketmq.broker.latency.BrokerFastFailure,基本上启动过程就完成了

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