日志重播分析

Hbase的日志重播分为启动时的日志重播与rs下线时的日志重播操作。

通过hbase.master.distributed.log.replay来控制日志的split是在region的reopen前执行还是reopen后执行

如果是true表示在reopen后执行,否则相反

Rs下线时的日志重播分析

master监听下线

master通过RegionServerTracker监听rs在zk上的节点，当节点被删除时(rs下线)。触发nodeDeleted

publicvoidnodeDeleted(Stringpath) {

if(path.startsWith(watcher.rsZNode)){

解析出zk中rs路径下的rs名称，并解析成ServerName实例。

StringserverName= ZKUtil.getNodeName(path);

....................此处部分日志打印信息没有显示

ServerNamesn= ServerName.parseServerName(serverName);

如果下线的rs在ServerManager的onlineServers中已经不包含，不做处理，

if(!serverManager.isServerOnline(sn)){

....................此处部分日志打印信息没有显示

return;

}

从RegionServerTracker.onlineServers列表中移出此rs

remove(sn);

执行ServerManager.expireServer进行下线处理

this.serverManager.expireServer(sn);

}

}

执行ServerManager.expireServer进行下线处理

publicsynchronizedvoidexpireServer(finalServerNameserverName){

....................此处部分代码没有显示

把rs添加到deadservers列表中。

this.deadservers.add(serverName);

从onlineServers列表中移出此rs

this.onlineServers.remove(serverName);

synchronized(onlineServers){

onlineServers.notifyAll();

}

从rsAdmins(对rs进行RPC调用的接口实现类)容器中移出此rs

this.rsAdmins.remove(serverName);

....................此处部分代码没有显示

检查此rs中是否包含meta的region，如果是，执行MetaServerShutdownHandler.否则执行ServerShutdownHandler

booleancarryingMeta=services.getAssignmentManager().isCarryingMeta(serverName);

if(carryingMeta){

this.services.getExecutorService().submit(newMetaServerShutdownHandler(this.master,

this.services,this.deadservers,serverName));

}else{

this.services.getExecutorService().submit(newServerShutdownHandler(this.master,

this.services,this.deadservers,serverName,true));

}

....................此处部分日志打印没有显示

}

MetaServerShutdownHandler.process方法处理流程:

publicvoidprocess()throwsIOException {

booleangotException=true;

try{

AssignmentManageram= this.services.getAssignmentManager();

try{

检查是否需要做hlog的split，生成此实例时，shouldSplitHlog的值为true

if(this.shouldSplitHlog){

LOG.info("Splittinghbase:meta logs for " +serverName);

检查hbase.master.distributed.log.replay配置是否设置为true,默认值为false

if(this.distributedLogReplay){

先对metaregion执行prepareLogReplay处理。

见MasterFileSystem.prepareLogReplay分析

Set<HRegionInfo>regions =newHashSet<HRegionInfo>();

regions.add(HRegionInfo.FIRST_META_REGIONINFO);

this.services.getMasterFileSystem().prepareLogReplay(serverName,regions);

}else{

否则在没有配置distributedLogReplay时，执行splitMetaLog对rs的日志进行split,等待split完成

见MasterFileSystem.splitMetaLog分析

this.services.getMasterFileSystem().splitMetaLog(serverName);

}

从AssignmentManager.RegionStates.lastAssignments中移出metaregion的分配。

am.getRegionStates().logSplit(HRegionInfo.FIRST_META_REGIONINFO);

}

}catch(IOExceptionioe){

....................此处部分代码没有显示

}

//Assign meta if we were carrying it.

//Check again: region may be assigned to other where because of RIT

//timeout

检查此server上还没有完成regionopen操作(regionInTransition还在)如果包含有metaregion,

if(am.isCarryingMeta(serverName)){

LOG.info("Server" + serverName+" was carrying META. Trying toassign.");

更新RegionStates中此region的状态为offline

从regionsInTransition中移出此region,

从serverHoldings中移出此server中metaregion的分配信息

从regionAssignments中移出此metaregion的分配信息

从regionsToReopen中移出此metaregion

从regionPlans中移出此metaregion

am.regionOffline(HRegionInfo.FIRST_META_REGIONINFO);

等待metaregion的分配,

通过hbase.catalog.verification.retries配置metaregion分配的重试次数,默认10次

通过hbase.catalog.verification.timeout配置每次分配重试的间隔时间,默认1000ms

verifyAndAssignMetaWithRetries();

如果meta在zk中的地址过期数据被删除,重新执行meta的分配,并等待meta分配完成

}elseif(!this.services.getCatalogTracker().isMetaLocationAvailable()){

//the meta location as per master is null. This could happen in casewhen meta assignment

//in previous run failed, while metaznodehas been updated to null. We should try to

//assign the meta again.

如果metaregion在zk中的地址没有注册的数据,执行metaregion的分配,并等待分配结束

通过hbase.catalog.verification.retries配置metaregion分配的重试次数,默认10次

通过hbase.catalog.verification.timeout配置每次分配重试的间隔时间,默认1000ms

verifyAndAssignMetaWithRetries();

}else{

LOG.info("METAhas been assigned to otherwhere, skip assigning.");

}

try{

如果distributedLogReplay配置为true,等待regionreplay的regionintranstion事务完成

也就是RegionStates.regionsInTransition中不在包含此metaregion的regionintransition

regionreplay的等待超时通过hbase.master.log.replay.wait.region.timeout配置，默认为15000ms

如果在超时的时间内没有完成regionintransition时，此方法返回false

if(this.shouldSplitHlog&&this.distributedLogReplay){

if(!am.waitOnRegionToClearRegionsInTransition(HRegionInfo.FIRST_META_REGIONINFO,

regionAssignmentWaitTimeout)){

....................此处部分代码没有显示

}

执行logsplit,并等待split完成,如果是distributedLogReplay时，

此时regionassign已经完成,开始spltlog

见MasterFileSystem.splitMetaLog分析

this.services.getMasterFileSystem().splitMetaLog(serverName);

}

}catch(Exceptionex){

....................此处部分代码没有显示

}

gotException=false;

}finally{

if(gotException){

//If we had an exception, this.deadServers.finish will be skipped insuper.process()

this.deadServers.finish(serverName);

}

}

执行此rs中非metaregion的日志重播与regionassign，

见ServerShutdownHandler.process方法处理流程

super.process();

}

MasterFileSystem.prepareLogReplay分析

此方法在hbase.master.distributed.log.replay配置为true时,分执行此操作

publicvoidprepareLogReplay(ServerNameserverName,Set<HRegionInfo>regions)throwsIOException {

一些必要的检查,检查是否设置有日志的分布式replay模式,要进行分布式日志的region列表是否为空

if(!this.distributedLogReplay){

return;

}

//mark regions in recovering state

if(regions ==null||regions.isEmpty()){

return;

}

try{

通过SplitLogManager.markRegionsRecoveringInZK在/hbase/recovering-regions中添加region路径

this.splitLogManager.markRegionsRecoveringInZK(serverName,regions);

}catch(KeeperExceptione) {

thrownewIOException(e);

}

}

执行distributedLogReplay

voidmarkRegionsRecoveringInZK(finalServerNameserverName, Set<HRegionInfo>userRegions)

throwsKeeperException {

一些必要的检查,检查是否设置有日志的分布式replay模式,要进行分布式日志的region列表是否为空

if(userRegions==null|| !this.distributedLogReplay){

return;

}

try{

this.recoveringRegionLock.lock();

//mark that we're creating recoveringznodes

更新SplitLogManager中最后一次recoveringnode的时间为当前时间

this.lastRecoveringNodeCreationTime= EnvironmentEdgeManager.currentTimeMillis();

开始迭代执行要replay的每一个region,如果是metaregion,此时只有一个迭代

for(HRegionInforegion: userRegions){

StringregionEncodeName=region.getEncodedName();

得到hbase.splitlog.zk.retries配置的在zk中创建子路径的最大重试次数,默认为3

longretries =this.zkretries;

do{

在zookeeper.znode.recovering.regions配置的路径下生成一个通过regionname为名称的子路径

默认为/hbase/recovering-regions/region-name

StringnodePath= ZKUtil.joinZNode(watcher.recoveringRegionsZNode,regionEncodeName);

longlastRecordedFlushedSequenceId= -1;

try{

得到region中的最大的seqid,此seqid在ServerManager.flushedSequenceIdByRegion中存储,

记录着region中flush的最大的seqid

longlastSequenceId=this.master.getServerManager().getLastFlushedSequenceId(

regionEncodeName.getBytes());

....................此处部分代码没有显示

检查在zk中的recovering-regions中是否已经包含此region,

byte[]data =ZKUtil.getData(this.watcher,nodePath);

if(data ==null){

如果recovering-regions中还不包含此region的replay信息,

把region的最后一次flush的seqid写入到replay路径下

ZKUtil.createSetData(this.watcher,nodePath,

ZKUtil.positionToByteArray(lastSequenceId));

}else{

如果recovering-regions中已经包含有此region的replay信息,

得到上一次region的recovering的seqid,

如果上一次的seqid小于当前region的最后一次flush的seqid,更新zk中此region的replay的seqid为最新的seqid

否则不做修改(上一次flush的seqid比记录的flush的seqid更加的新)

lastRecordedFlushedSequenceId= SplitLogManager.parseLastFlushedSequenceIdFrom(data);

if(lastRecordedFlushedSequenceId<lastSequenceId){

//update last flushed sequence id in the region level

ZKUtil.setData(this.watcher,nodePath,ZKUtil.positionToByteArray(lastSequenceId));

}

}

//go one level deeper with server name

在recovering-regions/region-name下生成当前下线的server子路径

nodePath= ZKUtil.joinZNode(nodePath,serverName.getServerName());

如果当前region的flush的seqid小于上一次的recovering中replay的seqid,

(上一次flush的seqid比记录的flush的seqid更加的新),更新region的lastflush seqid为上一次的seqid

if(lastSequenceId<=lastRecordedFlushedSequenceId){

//the newly assigned RS failed even before any flush to the region

lastSequenceId=lastRecordedFlushedSequenceId;

}

在/hbase/recovering-regions/region-name/server-name路径下记录最后一次flush的seqid.

ZKUtil.createSetData(this.watcher,nodePath,

ZKUtil.regionSequenceIdsToByteArray(lastSequenceId,null));

....................此处部分代码没有显示

break;

}catch(KeeperExceptione) {

....................此处部分代码没有显示

}

}while((--retries)> 0 && (!this.stopper.isStopped()));

}

}finally{

this.recoveringRegionLock.unlock();

}

}

MasterFileSystem.splitMetaLog分析

splitMetaLog传入需要执行split操作的server(下线的server),方法去调用splitLog方法，

由于此时只针对metaregion的hlog时行split,因此在splitLog方法时传入META_FILTER来区分是否metasplit

publicvoidsplitLog(finalSet<ServerName>serverNames,PathFilterfilter)throwsIOException {

longsplitTime =0, splitLogSize= 0;

从/hbase/WALs的日志路径下得到通过下线的servers命名的所有日志路径,老版本中.logs目录

如：/hbase/WALs/server-name1

并把下线的server路径名称更新为/hbase/WALs/server-name1-splitting路径

List<Path>logDirs =getLogDirs(serverNames);

把下线的所有rsserver添加到SplitLogManager.deadWorkers中，

等待SplitLogManager.TimeoutMonitor线程定期去处理,

见SplitLogManager.TimeoutMonitor线程分析

splitLogManager.handleDeadWorkers(serverNames);

splitTime= EnvironmentEdgeManager.currentTimeMillis();

执行hlogsplit操作，见SplitLogManager.splitLogDistributed分析

splitLogSize=splitLogManager.splitLogDistributed(serverNames,logDirs,filter);

splitTime= EnvironmentEdgeManager.currentTimeMillis()-splitTime;

....................此处部分代码没有显示,监控信息

}

MasterFileSystem.splitLog分析

splitLog传入需要执行split操作的server(下线的server),方法去调用splitLog方法，

由于此时只针对非metaregion的hlog时行split,

因此在splitLog方法时传入NON_META_FILTER来区分是否非metasplit

publicvoidsplitLog(finalSet<ServerName>serverNames,PathFilterfilter)throwsIOException {

longsplitTime =0, splitLogSize= 0;

从/hbase/WALs的日志路径下得到通过下线的servers命名的所有日志路径,老版本中.logs目录

如：/hbase/WALs/server-name1

并把下线的server路径名称更新为/hbase/WALs/server-name1-splitting路径

List<Path>logDirs =getLogDirs(serverNames);

把下线的所有rsserver添加到SplitLogManager.deadWorkers中，

等待SplitLogManager.TimeoutMonitor线程定期去处理,

见SplitLogManager.TimeoutMonitor线程分析

splitLogManager.handleDeadWorkers(serverNames);

splitTime= EnvironmentEdgeManager.currentTimeMillis();

执行hlogsplit操作，见SplitLogManager.splitLogDistributed分析

splitLogSize=splitLogManager.splitLogDistributed(serverNames,logDirs,filter);

splitTime= EnvironmentEdgeManager.currentTimeMillis()-splitTime;

....................此处部分代码没有显示,监控信息

}

SplitLogManager.splitLogDistributed分析

此方法主要用于对serverhlog根据region进行split操作，生成splittask，并等待split完成。

publiclongsplitLogDistributed(finalSet<ServerName>serverNames,finalList<Path>logDirs,

PathFilterfilter)throwsIOException {

....................此处部分代码没有显示,监控信息,日志信息

得到/hbase/WALs/server-name-splitting下的所有日志文件,

如果传入的filter为META_FILTER,那么只获取.meta的hlog文件,否则获取全部hlog文件

FileStatus[]logfiles= getFileList(logDirs,filter);

....................此处部分代码没有显示,监控信息,日志信息

longtotalSize =0;

TaskBatchbatch= newTaskBatch();

BooleanisMetaRecovery= (filter==null)?null:false;

for(FileStatuslf: logfiles){

....................此处部分代码没有显示,监控信息,日志信息

totalSize+=lf.getLen();

得到日志文件路径去掉/hbase的部分名称，如/WALs/server-name-splitting/aaa.meta

StringpathToLog= FSUtils.removeRootPath(lf.getPath(),conf);

1.把hlog的全路径去掉/hbase部分通过URLEncoder.encode进行转码(/会被转换成%2F)

2.把hlog的全路径添加到zookeeper.znode.splitlog配置的路径下默认为splitWAL，作为其子路径存在。

3.在SplitLogManager.tasks中添加一个Task实例,key为2中zk生成的path，value为生成的Task实例,

设置Task的status为IN_PROGRESS，并把task的batch实例为上面生成的TaskBatch实例(batch),

把batch中的installed加一，表示增加一个批量执行的Task

4.根据hbase.splitlog.zk.retries配置的zk重试次数,默认为3，

生成SplitLogTask实例，设置其originServer为master的ServerName

设置其state为ZooKeeperProtos.SplitLogTask.State.UNASSIGNED

在zk中注册此地址,并把SplitLogTask写入到此zk的路径下。

5.regionserver中监听zk的splitWAL的路径，

见regionserver中处理splitlog

6.master中通过SplitLogManager.nodeDataChanged来监听rs中SplitLogTask的状态修改。

见SplitLogManager.nodeDataChanged分析

if(!enqueueSplitTask(pathToLog,batch)) {

thrownewIOException("duplicatelog split scheduled for " +lf.getPath());

}

}

等待split操作完成,

a.batch中所有的Task.status为TerminationStatus.IN_PROGRESS的task个数为0

b.splitWAL路径下的所有子路径的个数为0

c.每次迭代都需要等待batch被nodeDataChanged或者其它地方对batch进行notify

waitForSplittingCompletion(batch,status);

//remove recovering regions from ZK

if(filter ==MasterFileSystem.META_FILTER/* reference comparison */){

....................此处部分代码没有显示,日志信息

isMetaRecovery=true;

}

删除zk的recovering-regions下对应的region路径下传入的servers子路径

(如果region下所有的servers子路径不存在,直接删除region子路径)

如果isMetaRecovery等于true表示只删除metaregion的recovering路径

this.removeRecoveringRegionsFromZK(serverNames,isMetaRecovery);

如果有日志split出现错误,直接throwIOException

if(batch.done!=batch.installed){

batch.isDead=true;

....................此处部分代码没有显示,日志信息

thrownewIOException(msg);

}

for(PathlogDir:logDirs){

status.setStatus("Cleaningup log directory...");

try{

删除WALs目录下对应的server-name-splitting的日志文件。

if(fs.exists(logDir)&& !fs.delete(logDir,false)){

LOG.warn("Unableto delete log src dir. Ignoring. "+ logDir);

}

}catch(IOExceptionioe){

....................此处部分代码没有显示,日志信息

}

SplitLogCounters.tot_mgr_log_split_batch_success.incrementAndGet();

}

....................此处部分代码没有显示,监控信息,日志信息

returntotalSize;

}

ServerShutdownHandler.process方法处理流程:

ServerShutdownHandler的处理流程主要对非metaregion的下线处理，region的重新分配,日志split

publicvoidprocess()throws IOException {

booleanhasLogReplayWork=false;

finalServerNameserverName=this.serverName;

try{

....................此处部分代码没有显示

AssignmentManageram= services.getAssignmentManager();

if(isCarryingMeta()// hbase:meta

||!am.isFailoverCleanupDone()){

this.services.getServerManager().processDeadServer(serverName,this.shouldSplitHlog);

return;

}

....................此处部分代码没有显示

NavigableMap<HRegionInfo,Result>hris =null;

while(!this.server.isStopped()){

try{

从meta表中进行scan,扫描出当前下线的regionserver中所有的userregion列表。

this.server.getCatalogTracker().waitForMeta();

hris= MetaReader.getServerUserRegions(this.server.getCatalogTracker(),

this.serverName);

break;

}catch(InterruptedExceptione){

Thread.currentThread().interrupt();

thrownewIOException("Interrupted",e)

}catch(IOExceptionioe){

....................此处部分代码没有显示

}

}

if(this.server.isStopped()){

thrownewIOException("Serveris stopped");

}

try{

shouldSplitHlog在ServerShutdownHandler实例生成时默认为true

if(this.shouldSplitHlog){

LOG.info("Splittinglogs for " + serverName+" before assignment.");

检查hbase.master.distributed.log.replay配置是否设置为true,默认值为false

if(this.distributedLogReplay){

LOG.info("Markregions in recovery before assignment.");

Set<ServerName>serverNames=newHashSet<ServerName>();

serverNames.add(serverName);

如果设置有distributedLogReplay，执行logsplit的预处理,

见MasterFileSystem.prepareLogReplay分析

this.services.getMasterFileSystem().prepareLogReplay(serverNames);

}else{

如果没有设置distributedLogReplay，执行logsplit,并等待split完成

见MasterFileSystem.splitLog分析

this.services.getMasterFileSystem().splitLog(serverName);

}

从RegionStates.lastAssignments中移出此server对应的所有region分配信息

从RegionStates.processedServers中移出超出时间限制的

通过hbase.master.maximum.logsplit.keeptime配置的时间的server,默认为7200000ms(2hour)

am.getRegionStates().logSplit(serverName);

}else{

LOG.info("Skippinglog splitting for " + serverName);

}

}catch(IOExceptionioe){

resubmit(serverName,ioe);

}

....................此处部分代码没有显示

1.从AssignmentManager.regionPlans中移出包含此server的regionplan,

2.从regionStates.serverHoldings中得到此server所有的regionassign,

如果region的状态为online/splitting/merging,把region的状态设置为offline

并从regionsInTransition与regionAssignments移出这些个region.

如果region的状态为splitting/merging时，删除region在zk中region-in-transition的注册信息

3.从regionsInTransition中找到所有此server中transition的

状态为PENDING_OPEN/OPENING/FAILED_OPEN/FAILED_CLOSE/OFFLINE的region,并返回

4.根据3返回的在regionsInTransition中的region,删除region在zk中region-in-transition的注册信息

zk中的路径通过zookeeper.znode.unassigned进行配置。

5.注意：3中返回的region是当前下线的server在assignments中不包含的,

同时在regionInTransition又包含,也就是这些个region准备在当前下线的server上启动,

但此时这个server挂掉了。此方法的主要作用是删除掉当前下线server中正在做transition的region的zk信息,

把这些个region的状态设置为offline,等待下面的代码逻辑重新执行分配.

List<HRegionInfo>regionsInTransition=am.processServerShutdown(serverName);

....................此处部分代码没有显示

把上面得到的正在做transition的regions添加到待分配的region列表中

List<HRegionInfo>toAssignRegions=newArrayList<HRegionInfo>();

toAssignRegions.addAll(regionsInTransition);

//Iterate regions that were on this server and assign them

if(hris !=null){

RegionStatesregionStates=am.getRegionStates();

迭代从meta表中得到的所有当前下线server的userregion,

for(Map.Entry<HRegionInfo,Result>e:hris.entrySet()){

HRegionInfohri= e.getKey();

如果此region在transition中已经包含,重新迭代下一次

if(regionsInTransition.contains(hri)){

continue;

}

StringencodedName=hri.getEncodedName();

Locklock =am.acquireRegionLock(encodedName);

try{

RegionStaterit= regionStates.getRegionTransitionState(hri);

检查region所在的table是否被删除/是否是disable的table,如果不是执行如下流程

if(processDeadRegion(hri,e.getValue(),am,server.getCatalogTracker())){

ServerNameaddressFromAM=regionStates.getRegionServerOfRegion(hri);

if(addressFromAM!=null&& !addressFromAM.equals(this.serverName)){

....................此处部分代码没有显示

continue;

}

if(rit !=null){

if(rit.getServerName()!=null&& !rit.isOnServer(serverName)){

....................此处部分代码没有显示

continue;

}

try{

....................此处部分代码没有显示

删除region在zk中region-in-transition的注册信息,zk中的路径通过zookeeper.znode.unassigned进行配置,

并更新region的状态为offline

ZKAssign.deleteNodeFailSilent(services.getZooKeeper(),hri);

regionStates.updateRegionState(hri,State.OFFLINE);

}catch(KeeperExceptionke) {

this.server.abort("UnexpectedZK exception deleting unassigned node "+ hri, ke);

return;

}

}elseif(regionStates.isRegionInState(

hri,State.SPLITTING_NEW,State.MERGING_NEW)){

如果region的状态是准备split或者准备merge时，重新设置region状态为offline

regionStates.regionOffline(hri);

}

添加此region到待分配的region列表中

toAssignRegions.add(hri);

}elseif(rit !=null){

region所在的table现在是disable的table,设置region状态为offline,

a.如果region在zk中的eventType为M_ZK_REGION_CLOSING/RS_ZK_REGION_CLOSED,从zk中删除此region的路径

zk中region-in-transition的注册信息,zk中的路径通过zookeeper.znode.unassigned进行配置

b.如果region在zk中的eventtype为RS_ZK_REGION_CLOSED/M_ZK_REGION_OFFLINE，从zk中删除此region的路径

if(rit.isPendingCloseOrClosing()

&&am.getZKTable().isDisablingOrDisabledTable(hri.getTable())){

....................此处部分代码没有显示

regionStates.updateRegionState(hri,State.OFFLINE);

am.deleteClosingOrClosedNode(hri,rit.getServerName());

am.offlineDisabledRegion(hri);

}else{

LOG.warn("THISSHOULD NOT HAPPEN: unexpected region in transition "

+rit+ " not to be assigned by SSH ofserver " +serverName);

}

}

}finally{

lock.unlock();

}

}

}

try{

执行region的批量assign操作

am.assign(toAssignRegions);

}catch(InterruptedExceptionie){

LOG.error("Caught" + ie+ " during round-robinassignment");

thrownewIOException(ie);

}

if(this.shouldSplitHlog&&this.distributedLogReplay){

//wait for region assignment completes

for(HRegionInfohri: toAssignRegions){

try{

此处只能是distributedLogReplay设置为true时，因为这时rs中不做logreplay,

distributedLogReplay设置为true时,region下不存在recovered.edits路径,因此openregion时replay不会执行,

所以此时等待region的open完成是可行的。等待每一个region的assign完成,

也就是assign时的RegionInTransition在RegionStates.regionsInTransition的处理完成(列表中不包含此region)

或者说等待分配的超时时间hbase.master.log.replay.wait.region.timeout过期,默认15000ms

在assign时会在zk中的region-in-transition注册一个region地址,等待rs处理,

此方法会不停止的迭代,直接timeout或者regionsInTransition中移出此region的transition,

每次迭代会让regionstates处于wait状态，等待AssignmentManager.nodeDataChanged/nodeDeleted对其notify

完成后通过AssignmentManager中的相关nodeDataChanged处理事件方法对regionsInTransition更新，

通过nodeDeleted处理事件对regionsInTransition移出

if(!am.waitOnRegionToClearRegionsInTransition(hri,regionAssignmentWaitTimeout)){

//Wait here is to avoid log replay hits current dead server and incur aRPC timeout

//when replay happens before region assignment completes.

LOG.warn("Region" + hri.getEncodedName()

+"didn't complete assignment in time");

}

}catch(InterruptedExceptionie){

thrownewInterruptedIOException("Caught" + ie

+"during waitOnRegionToClearRegionsInTransition");

}

}

//submit logReplay work

如果设置distributedLogReplay为true，此时regionassign完成,执行logsplit,并等待split完成

见MasterFileSystem.splitLog分析

this.services.getExecutorService().submit(

newLogReplayHandler(this.server,this.services,this.deadServers,this.serverName));

hasLogReplayWork=true;

}

}finally{

this.deadServers.finish(serverName);

}

if(!hasLogReplayWork){

LOG.info("Finishedprocessing of shutdown of " +serverName);

}

}

regionserver中处理splitlog

regionserver中通过regionserver启动时启动的SplitLogWorker线程,

通过其的run方法监听master在zk中生成splitWAL，一但master在zk中注册splitWAL路径成功,

执行taskLoop方法默认5s进行一次splitlog的检查(线程等待,timeout为5000ms),

通过nodeChildrenChanged来监听zk中splitWAL子路径的修改,并notify此线程,

通过nodeDataChanged来更新每一个SplitLogTask的状态更新，

publicvoidrun(){

try{

....................此处部分代码没有显示

//wait for master to create the splitLogZnode

intres = -1;

while(res == -1&& !exitWorker){

try{

监听master对zk中splitWAL的注册

res= ZKUtil.checkExists(watcher,watcher.splitLogZNode);

}catch(KeeperExceptione) {

//ignore

LOG.warn("Exceptionwhen checking for " +watcher.splitLogZNode +" ... retrying",e);

}

if(res == -1){

try{

....................此处部分代码没有显示

Thread.sleep(1000);

}catch(InterruptedExceptione){

....................此处部分代码没有显示

exitWorker=true;

break;

}

}

}

if(!exitWorker){

定期检查并启动执行splithlog的处理

taskLoop();

}

}catch(Throwablet){

....................此处部分代码没有显示

}finally{

LOG.info("SplitLogWorker" + this.serverName+" exiting");

}

}

检查并执行splithlog

privatevoidtaskLoop(){

while(!exitWorker){

intseq_start =taskReadySeq;

得到所有的需要进行logsplit的servername的路径

List<String>paths =getTaskList();

if(paths ==null){

LOG.warn("Couldnot get tasks, did someone remove "+

this.watcher.splitLogZNode+" ... worker thread exiting.");

return;

}

//pick metawalfirstly

首先定义一个先执行的servernamehlog split的路径值,默认为随机取一个下标

如果要split的server中包含有meta的region，那么先从meta的server开始执行

intoffset =(int)(Math.random()*paths.size());

for(inti = 0; i< paths.size();i ++){

if(HLogUtil.isMetaFile(paths.get(i))){

offset=i;

break;

}

}

intnumTasks =paths.size();

for(inti = 0; i< numTasks;i++) {

计算执行顺序,从offset开始执行,如：paths.size()=6,offset=5,那么执行顺序为501234

intidx = (i+ offset) %paths.size();

//don't call ZKSplitLog.getNodeName() because that will lead to

//double encoding of the path name

每一个server最大同时执行splithlog的task个数通过hbase.regionserver.wal.max.splitters配置，默认为2

得到现在活着的所有的regionserver列表,根据要split的server个数,

平均下来后计算此server最多要执行多少个splttask,

最多同时执行个数不超过hbase.regionserver.wal.max.splitters配置,每次执行tasksInProgress值加一

if(this.calculateAvailableSplitters(numTasks)> 0) {

如果此server还有能力执行splithlog task，

更新zk中splitWAL中此servername(待split)的SplitLogTask为SplitLogTask.Owned,

并把当前执行split的rs更新到zk中。生成HLogSplitterHandler实例，并启动线程执行此处理程序

把tasksInProgress的正在处理的splittask的值加一,见HLogSplitterHandler.process流程分析

等待500-1000ms在重新执行下一次分配,这样能保证其它的rs也能分配到任务

注意：此部分逻辑第一次执行此方法时不会执行，因为第一次执行时zk中splitWAL路径下可能为空,

直接进入下面部分，让此线程进入wait状态，等待nodeChildrenChanged来进行notify

grabTask(ZKUtil.joinZNode(watcher.splitLogZNode,paths.get(idx)));

}else{

LOG.debug("Currentregion server " + this.serverName+" has "

+this.tasksInProgress.get()+" tasks in progress and can'ttake more.");

break;

}

if(exitWorker){

return;

}

}

SplitLogCounters.tot_wkr_task_grabing.incrementAndGet();

synchronized(taskReadyLock){

此次任务执行完成，zk中splitWAL在任务执行到此时还没有更新的rs下线被注册进来

while(seq_start==taskReadySeq){

try{

线程进行等待状态，等待nodeChildrenChanged来进行notify

taskReadyLock.wait(checkInterval);

if(this.server!=null){

//check to see if we have stale recovering regions in our internalmemory state

如果是设置有distributedLogReplay模式，此时在regionopen后才开始执行splitlog,

那么得到要进行splitlog的region列表。迭代每一个region，

从recovering-regions中检查是否此region需要splitlog,

如果recovering-regions中不存在此region,从rs中的recoveringRegions列表中移出此region

并设置此Hregion的recovering的值为false.

开始回到taskLoop方法的顶部，重新对这部分region进行splitlog

Map<String,HRegion>recoveringRegions=this.server.getRecoveringRegions();

if(!recoveringRegions.isEmpty()){

//Make a local copy to prevent ConcurrentModificationException whenother threads

//modify recoveringRegions

List<String>tmpCopy =newArrayList<String>(recoveringRegions.keySet());

for(Stringregion: tmpCopy){

StringnodePath= ZKUtil.joinZNode(this.watcher.recoveringRegionsZNode,region);

try{

if(ZKUtil.checkExists(this.watcher,nodePath)== -1) {

HRegionr= recoveringRegions.remove(region);

if(r != null){

r.setRecovering(false);

}

LOG.debug("Markrecovering region:" + region+" up.");

}else{

....................此处部分代码没有显示

break;

}

}catch(KeeperExceptione) {

....................此处部分代码没有显示

break;

}

}

}

}

}catch(InterruptedExceptione){

....................此处部分代码没有显示

exitWorker=true;

return;

}

}

}

}

}

HlogSplitterHandler.process处理流程分析

HlogSplitterHandler是具体对hlog进行处理的handler,通过其传入的TaskExecutor.exec方法执行,

TaskExecutor是在SplitLogWorker实例生成时在构造方法中生成的一个匿名实现类,

publicHLogSplitterHandler(finalServerserver,String curTask,

finalMutableIntcurTaskZKVersion,

CancelableProgressablereporter,

AtomicIntegerinProgressTasks,TaskExecutorsplitTaskExecutor){

设置EventType为RS_LOG_REPLAY

super(server,EventType.RS_LOG_REPLAY);

this.curTask=curTask;

this.wal= ZKSplitLog.getFileName(curTask);

this.reporter=reporter;

this.inProgressTasks=inProgressTasks;

把regionserver中执行splitlog的task的值加一,表示占用一个执行位置

this.inProgressTasks.incrementAndGet();

this.serverName=server.getServerName();

this.zkw=server.getZooKeeper();

this.curTaskZKVersion=curTaskZKVersion;

见SplitLogWorker的构造方法最后一个参数

this.splitTaskExecutor=splitTaskExecutor;

}

publicvoidprocess()throws IOException {

longstartTime =System.currentTimeMillis();

try{

执行splitlog的处理程序,见下面的SplitLogTaskExecutor.exec处理分析，并得到流程执行的返回状态

Statusstatus =this.splitTaskExecutor.exec(wal,reporter);

switch(status) {

caseDONE:

成功结束，调用endTask结束任务，

设置zk中splitWAL路径的servername中SplitLogTask的状态为SplitLogTask.Done

endTask(zkw,newSplitLogTask.Done(this.serverName),

SplitLogCounters.tot_wkr_task_done,curTask,curTaskZKVersion.intValue());

break;

casePREEMPTED:

如果splittask是一个抢占的资源,不做处理

SplitLogCounters.tot_wkr_preempt_task.incrementAndGet();

LOG.warn("taskexecution prempted " + wal);

break;

caseERR:

执行过程错误，调用endTask结束任务,

设置zk中splitWAL路径的servername中SplitLogTask的状态为SplitLogTask.Err

if(server!=null&& !server.isStopped()){

endTask(zkw,newSplitLogTask.Err(this.serverName),

SplitLogCounters.tot_wkr_task_err,curTask,curTaskZKVersion.intValue());

break;

}

//if the RS is exiting then there is probably a tons of stuff

//that can go wrong. Resign instead of signaling error.

//$FALL-THROUGH$

caseRESIGNED:

如果资源的task执行被放弃,调用endTask结束任务,

设置zk中splitWAL路径的servername中SplitLogTask的状态为SplitLogTask.Resigned

if(server!=null&&server.isStopped()){

LOG.info("taskexecution interrupted because worker is exiting "+ curTask);

}

endTask(zkw,newSplitLogTask.Resigned(this.serverName),

SplitLogCounters.tot_wkr_task_resigned,curTask,curTaskZKVersion.intValue());

break;

}

}finally{

LOG.info("worker" + serverName+" done with task "+curTask +" in "

+ (System.currentTimeMillis()-startTime)+"ms");

把regionserver中的splitlog task的值减一，表示有一个空闲的位置

this.inProgressTasks.decrementAndGet();

}

}

SplitLogTaskExecutor.exec处理分析:

publicStatusexec(Stringfilename,CancelableProgressablep) {

Pathrootdir;

FileSystemfs;

try{

rootdir=FSUtils.getRootDir(conf);

fs=rootdir.getFileSystem(conf);

}catch(IOExceptione){

LOG.warn("couldnot find root dir or fs", e);

如果得到hdfs中/hbase目录出错或生成/hbase的FileSystem出错时,返回RESIGNED(放弃)

returnStatus.RESIGNED;

}

//TODOhave to correctly figure out when log splitting has been

//interrupted or has encountered a transient error and when it has

//encountered a bad non-retry-able persistent error.

Try{

执行splitlog操作，生成一个SplitLogFile实例，并执行其splitLogFile方法，

方法执行返回trueor false,执行过程中定期向zk中此hlogreplay的路径发送心跳，如果心跳发送失败返回false

发送心跳的间隔通过hbase.splitlog.report.period配置，默认为hbase.splitlog.manager.timeout(120000)/3

发送心跳其实就是定期在zk中重新注册此servername,并得到上一次注册的version,

如果上一次version小于1表示PREEMPTED（此server有资源抢占）

1.通过hbase.regionserver.hlog.splitlog.buffersize配置读取源hlog的buffer大小，默认为128*1024*1024

2.通过hbase.regionserver.hlog.splitlog.writer.threads配置OutputSink的写入线程个数

3.配置hbase.regionserver.wal.logreplay.batch.size，默认为64

4.如果distributedLogReplay设置为true,生成的OutputSink为HLogSplitter.LogReplayOutputSink/

否则生成HLogSplitter.LogRecoveredEditsOutputSink实例

5.通过hbase.hlog.split.skip.errors配置是否跳过spliterror,默认为false

6.通过hbase.splitlog.report.interval.loglines配置每次读取的行数，默认为1024

读取过程中如果hlog的entity的seqid小于region中的seqid或者cocovering-regions中存储的seqid,continue.

数据在output时，根据regionname，在regionname下创建一个recovered.edits目录，并写入hlog数据到此目录下

具体请参见HLogSplitter.splitLogFile方法源代码。

if(!HLogSplitter.splitLogFile(rootdir,fs.getFileStatus(newPath(rootdir,filename)),

fs,conf,p,sequenceIdChecker,watcher)) {

此server有资源抢占,主要是在zk上定期注册此server对hlog的split

returnStatus.PREEMPTED;

}

}catch(InterruptedIOExceptioniioe){

LOG.warn("logsplitting of " + filename+" interrupted, resigning",iioe);

returnStatus.RESIGNED;

}catch(IOExceptione){

Throwablecause= e.getCause();

if(einstanceofRetriesExhaustedException

&& (causeinstanceofNotServingRegionException

||causeinstanceofConnectException

||causeinstanceofSocketTimeoutException)) {

LOG.warn("logreplaying of " + filename+" can't connect to the targetregionserver, "

+"resigning",e);

returnStatus.RESIGNED;

}elseif(causeinstanceofInterruptedException) {

LOG.warn("logsplitting of " + filename+" interrupted, resigning",e);

returnStatus.RESIGNED;

}elseif(causeinstanceofKeeperException){

LOG.warn("logsplitting of " + filename+" hit ZooKeeper issue,resigning",e);

returnStatus.RESIGNED;

}

LOG.warn("logsplitting of " + filename+" failed, returning error",e);

returnStatus.ERR;

}

returnStatus.DONE;

}

}

SplogLogWorker.nodeDataChanged方法中监听到zk的状态修改时,如果状态不是如下状态是,调用stopTask结束线程

Stringtaskpath= currentTask;

if(taskpath!=null&&taskpath.equals(path)){

//have to compare data. cannot compare version because then there

//will be race with attemptToOwnTask()

//cannot just check whether the node has been transitioned to

//UNASSIGNED because by the time this worker sets the data watch

//the node might have made two transitions - from owned by this

//worker to unassigned to owned by another worker

if(!slt.isOwned(this.serverName)&&

!slt.isDone(this.serverName)&&

!slt.isErr(this.serverName)&&

!slt.isResigned(this.serverName)){

LOG.info("task" + taskpath+" preempted from "+

serverName+", current task state and owner="+slt.toString());

stopTask();

}

}

结束线程的执行过程

voidstopTask() {

LOG.info("Sendinginterrupt to stop the worker thread");

worker.interrupt();//TODOinterrupt often gets swallowed, do what else?

}

SplitLogManager.nodeDataChanged流程分析

regionserver中执行splitlog操作，并根据执行情况修改zk中splitWAL中SplitLogTask的状态。

SplitLogManager.nodeDataChanged在master端对zk中splitWAL进行监听，

从tasks列表中找到对应修改的task,把task的状态从IN_PROGRESS修改为SUCCESS,

设置task对应的TaskBatch的done或error的值加一。调用TaskBatch.notify方法叫醒线程的等待。

在waitForSplittingCompletion方法中会每执行一次检查把TaskBatch.wait，因此需要对其做notify

Regionopen数据重播分析

HregionServer.openRegion-->OpenRegionHandler.process-->openRegion-->

Hregion.openRegion-->生成HRegion实例，并调用实例的r.openHRegion(reporter)-->initialize

-->initializeRegionInternals-->initializeRegionStores-->replayRecoveredEditsIfAny

注意：日志重播时传入的每一个store中最大的seqid是不包含blukload的hfile的seqid，

而regionopen时得到并计算nextsequence id的所有store中最大的seqid是包含blukload的hfile的seqid

protectedlongreplayRecoveredEditsIfAny(finalPathregiondir,

Map<byte[],Long>maxSeqIdInStores,

finalCancelableProgressablereporter,finalMonitoredTaskstatus)

throwsUnsupportedEncodingException, IOException {

取出所有的store中flush到磁盘上的所有store中最小的一个seqid

longminSeqIdForTheRegion= -1;

for(LongmaxSeqIdInStore:maxSeqIdInStores.values()){

if(maxSeqIdInStore<minSeqIdForTheRegion||minSeqIdForTheRegion== -1) {

minSeqIdForTheRegion=maxSeqIdInStore;

}

}

longseqid =minSeqIdForTheRegion;

FileSystemfs =this.fs.getFileSystem();

取出region目录下recovered.edits子路径下所有的文件，但不包含结尾是.temp的文件,并根据文件名称排序返回

hlog在region下的文件名称是此文件对应的最大seqid,也就是按seqid从小到大排序。

NavigableSet<Path>files =HLogUtil.getSplitEditFilesSorted(fs,regiondir);

if(LOG.isDebugEnabled()){

LOG.debug("Found" + (files==null? 0 :files.size())

+"recovered edits file(s) under " +regiondir);

}

没有需要重播的日志文件，直接返回当前所有的store中最小的seqid,如果是表示不需要进行replay

if(files ==null||files.isEmpty())returnseqid;

for(Pathedits:files) {

检查日志文件是否存在

if(edits ==null|| !fs.exists(edits)){

LOG.warn("Nullor non-existent edits file: " +edits);

continue;

}

检查文件大小是否为空，如果是空文件直接删除,如果是表示不需要进行replay

if(isZeroLengthThenDelete(fs,edits))continue;

longmaxSeqId =Long.MAX_VALUE;

StringfileName= edits.getName();

检查此文件中最大的seqid是否小于region是所有store中最小的seqid,如果是表示此文件不需要进行replay

maxSeqId= Math.abs(Long.parseLong(fileName));

if(maxSeqId<=minSeqIdForTheRegion){

if(LOG.isDebugEnabled()){

Stringmsg= "Maximum sequenceid for this logis " +maxSeqId

+"and minimum sequenceid for the region is "+minSeqIdForTheRegion

+",skipped the whole file, path=" +edits;

LOG.debug(msg);

}

continue;

}

try{

得到replay的edits中每一个kv,并根据kv得到对应的store,

如果kv中的seqid小于store中最大的seqid，此kv不需要replay,

否则把kv添加到store中，得到添加的kvsize,把size添加到：

a.RegionServerAccounting.replayEditsPerRegion中对应的region的大小中，

表示此region中replay的memory使用情况

b.RegionServerAccounting.atomicGlobalMemstoreSize中，表示全局的memstore使用情况

c.添加到此region的memstore中，HRegion.memstoreSize,表示当前region的memory使用情况

d.检查memstore是否达到flush的值，通过hbase.hregion.memstore.flush.size配置，默认1024*1024*128L

如果达到memstore的flush值，对memstore进行flush

f.返回最新的seqid

seqid=replayRecoveredEdits(edits,maxSeqIdInStores,reporter);

}catch(IOExceptione){

出现replay错误，检查hbase.hregion.edits.replay.skip.errors是否配置为true

老版本使用hbase.skip.errors进行配置，默认值为false,表示不跳过error

booleanskipErrors=conf.getBoolean(

HConstants.HREGION_EDITS_REPLAY_SKIP_ERRORS,

conf.getBoolean(

"hbase.skip.errors",

HConstants.DEFAULT_HREGION_EDITS_REPLAY_SKIP_ERRORS));

if(conf.get("hbase.skip.errors")!=null){

LOG.warn(

"Theproperty 'hbase.skip.errors' has been deprecated. Please use "+

HConstants.HREGION_EDITS_REPLAY_SKIP_ERRORS+" instead.");

}

如果配置有跳过replayerror，把此edits文件重命名为editsname.systime,并remove到region的根目录下

if(skipErrors){

Pathp= HLogUtil.moveAsideBadEditsFile(fs,edits);

LOG.error(HConstants.HREGION_EDITS_REPLAY_SKIP_ERRORS

+"=trueso continuing. Renamed " +edits+

"as " +p,e);

}else{

throwe;

}

}

}

//The edits size added into rsAccounting during this replaying will not

//be required any more. So just clear it.

把RegionServerAccounting.replayEditsPerRegion中此region对应的replaykvsize清空

if(this.rsAccounting!=null){

this.rsAccounting.clearRegionReplayEditsSize(this.getRegionName());

}

如果进行了replay,那么当前replay后的seqid一定是大于原来的store的seqid，强制对region进行flush

if(seqid >minSeqIdForTheRegion){

//Then we added some edits to memory. Flush and cleanup split editfiles.

internalFlushcache(null,seqid,status);

}

//Now delete the content of recovered edits. We're done w/ them.

删除region下所有的recovered.edits下的文件

for(Pathfile:files) {

if(!fs.delete(file,false)){

LOG.error("Faileddelete of " + file);

}else{

LOG.debug("Deletedrecovered.edits file=" + file);

}

}

returnseqid;

}

distributedLogReplay为true的日志重播

通过hbase.master.distributed.log.replay配置的值为true时，在splitLog时，

生成HLogSplitter实例时OutputSink的实现会选择HLogSplitter.LogReplayOutputSink，

此实现不经过recovered.edits目录，直接把数据replay到region中。具体实现请查看相关源代码