我们可以知道，broker的消息完全顺序地存储在commitLog上，且每条消息的大小不一致，如果我们根据不同的主题查，或者根据消息id查找都要遍历整个commitLog文件，那肯定是不合理的。(要提一下，消息的一个主题topic，在一个broker上可以分成多个消息队列，默认是4个，也就是消息队列是基于topic+broker)，所以RocketMQ采用了ConsumerQueue文件存储定长的索引数据(20字节，8字节commitLog偏移量+4字节消息长度size+4字节tagHashCode)；采用了index文件存储id对应的消息的offset。
DefaultMessageStore的ReputMessageService服务专门解决这个问题，我们重点看下。ReputMessageService的启动在DefaultMessageStore的启动中。
@Override
public void run() {
DefaultMessageStore.log.info(this.getServiceName() + " service started");
while (!this.isStopped()) {
try {
Thread.sleep(1);
this.doReput();
} catch (Exception e) {
DefaultMessageStore.log.warn(this.getServiceName() + " service has exception. ", e);
}
}
DefaultMessageStore.log.info(this.getServiceName() + " service end");
} private void doReput() {
for (boolean doNext = true; this.isCommitLogAvailable() && doNext; ) {
if (DefaultMessageStore.this.getMessageStoreConfig().isDuplicationEnable()
&& this.reputFromOffset >= DefaultMessageStore.this.getConfirmOffset()) {
break;
}
SelectMappedBufferResult result = DefaultMessageStore.this.commitLog.getData(reputFromOffset);
if (result != null) {
try {
this.reputFromOffset = result.getStartOffset();
for (int readSize = 0; readSize < result.getSize() && doNext; ) {
DispatchRequest dispatchRequest =
DefaultMessageStore.this.commitLog.checkMessageAndReturnSize(result.getByteBuffer(), false, false);
int size = dispatchRequest.getMsgSize();
if (dispatchRequest.isSuccess()) {
if (size > 0) {
DefaultMessageStore.this.doDispatch(dispatchRequest);
if (BrokerRole.SLAVE != DefaultMessageStore.this.getMessageStoreConfig().getBrokerRole()
&& DefaultMessageStore.this.brokerConfig.isLongPollingEnable()) {
DefaultMessageStore.this.messageArrivingListener.arriving(dispatchRequest.getTopic(),
dispatchRequest.getQueueId(), dispatchRequest.getConsumeQueueOffset() + 1,
dispatchRequest.getTagsCode(), dispatchRequest.getStoreTimestamp(),
dispatchRequest.getBitMap(), dispatchRequest.getPropertiesMap());
}
this.reputFromOffset += size;
readSize += size;
if (DefaultMessageStore.this.getMessageStoreConfig().getBrokerRole() == BrokerRole.SLAVE) {
DefaultMessageStore.this.storeStatsService
.getSinglePutMessageTopicTimesTotal(dispatchRequest.getTopic()).incrementAndGet();
DefaultMessageStore.this.storeStatsService
.getSinglePutMessageTopicSizeTotal(dispatchRequest.getTopic())
.addAndGet(dispatchRequest.getMsgSize());
}
} else if (size == 0) {
this.reputFromOffset = DefaultMessageStore.this.commitLog.rollNextFile(this.reputFromOffset);
readSize = result.getSize();
}
} else if (!dispatchRequest.isSuccess()) {
if (size > 0) {
log.error("[BUG]read total count not equals msg total size. reputFromOffset={}", reputFromOffset);
this.reputFromOffset += size;
} else {
doNext = false;
if (DefaultMessageStore.this.brokerConfig.getBrokerId() == MixAll.MASTER_ID) {
log.error("[BUG]the master dispatch message to consume queue error, COMMITLOG OFFSET: {}",
this.reputFromOffset);
this.reputFromOffset += result.getSize() - readSize;
}
}
}
}
} finally {
result.release();
}
} else {
doNext = false;
}
}
} public SelectMappedBufferResult getData(final long offset, final boolean returnFirstOnNotFound) {
int mappedFileSize = this.defaultMessageStore.getMessageStoreConfig().getMapedFileSizeCommitLog();
MappedFile mappedFile = this.mappedFileQueue.findMappedFileByOffset(offset, returnFirstOnNotFound);
if (mappedFile != null) {
int pos = (int) (offset % mappedFileSize);
SelectMappedBufferResult result = mappedFile.selectMappedBuffer(pos);
return result;
}
return null;
} private final long startOffset;
private final ByteBuffer byteBuffer;
private int size;
private MappedFile mappedFile;根据pos与定位到的mappedFile，取出相应的数据存入byteBuffer，并将数据封装在SelectMappedBufferResult中返回。
然后调用了checkMessageAndReturnSize，解析读出的数据封装成DispatchRequest并返回。如果成功，且消息的大小大于0，那么调用doDispatch方法分发消息至consumequeue,index文件。
public void doDispatch(DispatchRequest req) {
for (CommitLogDispatcher dispatcher : this.dispatcherList) {
dispatcher.dispatch(req);
}
} this.dispatcherList = new LinkedList<>();
this.dispatcherList.addLast(new CommitLogDispatcherBuildConsumeQueue());
this.dispatcherList.addLast(new CommitLogDispatcherBuildIndex()); class CommitLogDispatcherBuildConsumeQueue implements CommitLogDispatcher {
@Override
public void dispatch(DispatchRequest request) {
final int tranType = MessageSysFlag.getTransactionValue(request.getSysFlag());
switch (tranType) {
case MessageSysFlag.TRANSACTION_NOT_TYPE:
case MessageSysFlag.TRANSACTION_COMMIT_TYPE:
DefaultMessageStore.this.putMessagePositionInfo(request);
break;
case MessageSysFlag.TRANSACTION_PREPARED_TYPE:
case MessageSysFlag.TRANSACTION_ROLLBACK_TYPE:
break;
}
}
} public void putMessagePositionInfo(DispatchRequest dispatchRequest) {
ConsumeQueue cq = this.findConsumeQueue(dispatchRequest.getTopic(), dispatchRequest.getQueueId());
cq.putMessagePositionInfoWrapper(dispatchRequest);
} public void putMessagePositionInfoWrapper(DispatchRequest request) {
final int maxRetries = 30;
boolean canWrite = this.defaultMessageStore.getRunningFlags().isCQWriteable();
for (int i = 0; i < maxRetries && canWrite; i++) {
long tagsCode = request.getTagsCode();
if (isExtWriteEnable()) {
ConsumeQueueExt.CqExtUnit cqExtUnit = new ConsumeQueueExt.CqExtUnit();
cqExtUnit.setFilterBitMap(request.getBitMap());
cqExtUnit.setMsgStoreTime(request.getStoreTimestamp());
cqExtUnit.setTagsCode(request.getTagsCode());
long extAddr = this.consumeQueueExt.put(cqExtUnit);
if (isExtAddr(extAddr)) {
tagsCode = extAddr;
} else {
log.warn("Save consume queue extend fail, So just save tagsCode! {}, topic:{}, queueId:{}, offset:{}", cqExtUnit,
topic, queueId, request.getCommitLogOffset());
}
}
boolean result = this.putMessagePositionInfo(request.getCommitLogOffset(),
request.getMsgSize(), tagsCode, request.getConsumeQueueOffset());
if (result) {
this.defaultMessageStore.getStoreCheckpoint().setLogicsMsgTimestamp(request.getStoreTimestamp());
return;
} else {
// XXX: warn and notify me
log.warn("[BUG]put commit log position info to " + topic + ":" + queueId + " " + request.getCommitLogOffset()
+ " failed, retry " + i + " times");
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
log.warn("", e);
}
}
}
// XXX: warn and notify me
log.error("[BUG]consume queue can not write, {} {}", this.topic, this.queueId);
this.defaultMessageStore.getRunningFlags().makeLogicsQueueError();
}
先判断ConsumerQueue是否可写，如果配置了消息队列的额外信息的可写，那么构造ConsumeQueueExt的内部类存储单元的CqExtUnit的实例，保存消息的bitMap、storeTime、TagsCode等信息，并加入到ConsumeQueueExt中管理。
通过putMessagePositionInfo方法，将消息写入到ConsumerQueue中的逻辑文件mappedFileQueue中。
private boolean putMessagePositionInfo(final long offset, final int size, final long tagsCode,
final long cqOffset) {
if (offset <= this.maxPhysicOffset) {
return true;
}
this.byteBufferIndex.flip();
this.byteBufferIndex.limit(CQ_STORE_UNIT_SIZE);
this.byteBufferIndex.putLong(offset);
this.byteBufferIndex.putInt(size);
this.byteBufferIndex.putLong(tagsCode);
final long expectLogicOffset = cqOffset * CQ_STORE_UNIT_SIZE;
MappedFile mappedFile = this.mappedFileQueue.getLastMappedFile(expectLogicOffset);
if (mappedFile != null) {
if (mappedFile.isFirstCreateInQueue() && cqOffset != 0 && mappedFile.getWrotePosition() == 0) {
this.minLogicOffset = expectLogicOffset;
this.mappedFileQueue.setFlushedWhere(expectLogicOffset);
this.mappedFileQueue.setCommittedWhere(expectLogicOffset);
this.fillPreBlank(mappedFile, expectLogicOffset);
log.info("fill pre blank space " + mappedFile.getFileName() + " " + expectLogicOffset + " "
+ mappedFile.getWrotePosition());
}
if (cqOffset != 0) {
long currentLogicOffset = mappedFile.getWrotePosition() + mappedFile.getFileFromOffset();
if (expectLogicOffset < currentLogicOffset) {
log.warn("Build consume queue repeatedly, expectLogicOffset: {} currentLogicOffset: {} Topic: {} QID: {} Diff: {}",
expectLogicOffset, currentLogicOffset, this.topic, this.queueId, expectLogicOffset - currentLogicOffset);
return true;
}
if (expectLogicOffset != currentLogicOffset) {
LOG_ERROR.warn(
"[BUG]logic queue order maybe wrong, expectLogicOffset: {} currentLogicOffset: {} Topic: {} QID: {} Diff: {}",
expectLogicOffset,
currentLogicOffset,
this.topic,
this.queueId,
expectLogicOffset - currentLogicOffset
);
}
}
this.maxPhysicOffset = offset;
return mappedFile.appendMessage(this.byteBufferIndex.array());
}
return false;
}先判断偏移量，如果小于maxPhysicOffset说明已经重复放过，那么返回成功。将信息(offset、size、tagCodes)存入到byteBuffer，并计算偏移量求出对应的MappedFile。如果mappedFile是第一个且队列位置非第一个且mappedFile未写入内容，那么在指定写入位置前面填充空白占位符。如果consumeQueue存储位置不合法，那么日志报错。然后将maxPhysicOffset更新为offset，并且调用appendMessage方法实际向ConsumerQueue的指定mappedFile写入20字节的数据。
如果上面步骤成功，那么将消息在ConsumerQuquq中的存储时间设为storeCheckpoint的logicMsg存储时间戳。否则sleep1s然后重试，知道超过重试次数或者成功。
找了下storePath 跟 queueDir
System.getProperty("user.home") + File.separator + "store" + File.separator + "consumequeue"
+ File.separator + topic + File.separator + queueId; public int getMapedFileSizeConsumeQueue() {
int factor = (int) Math.ceil(this.mapedFileSizeConsumeQueue / (ConsumeQueue.CQ_STORE_UNIT_SIZE * 1.0));
return (int) (factor * ConsumeQueue.CQ_STORE_UNIT_SIZE);
}30W记录，每条记录20字节。
再理一理，一个指定topic、指定queueId对应一个ConsumerQueue，ConsumerQueue管理着一个大小默认为mappedFileSize的mappedFileQueue可存储30W条记录。
下面我们来分析下CommitlogDispatcherBuildIndex
class CommitLogDispatcherBuildIndex implements CommitLogDispatcher {
@Override
public void dispatch(DispatchRequest request) {
if (DefaultMessageStore.this.messageStoreConfig.isMessageIndexEnable()) {
DefaultMessageStore.this.indexService.buildIndex(request);
}
}
} public void buildIndex(DispatchRequest req) {
IndexFile indexFile = retryGetAndCreateIndexFile();
if (indexFile != null) {
long endPhyOffset = indexFile.getEndPhyOffset();
DispatchRequest msg = req;
String topic = msg.getTopic();
String keys = msg.getKeys();
if (msg.getCommitLogOffset() < endPhyOffset) {
return;
}
final int tranType = MessageSysFlag.getTransactionValue(msg.getSysFlag());
switch (tranType) {
case MessageSysFlag.TRANSACTION_NOT_TYPE:
case MessageSysFlag.TRANSACTION_PREPARED_TYPE:
case MessageSysFlag.TRANSACTION_COMMIT_TYPE:
break;
case MessageSysFlag.TRANSACTION_ROLLBACK_TYPE:
return;
}
if (req.getUniqKey() != null) {
indexFile = putKey(indexFile, msg, buildKey(topic, req.getUniqKey()));
if (indexFile == null) {
log.error("putKey error commitlog {} uniqkey {}", req.getCommitLogOffset(), req.getUniqKey());
return;
}
}
if (keys != null && keys.length() > 0) {
String[] keyset = keys.split(MessageConst.KEY_SEPARATOR);
for (int i = 0; i < keyset.length; i++) {
String key = keyset[i];
if (key.length() > 0) {
indexFile = putKey(indexFile, msg, buildKey(topic, key));
if (indexFile == null) {
log.error("putKey error commitlog {} uniqkey {}", req.getCommitLogOffset(), req.getUniqKey());
return;
}
}
}
}
} else {
log.error("build index error, stop building index");
}
} public IndexFile retryGetAndCreateIndexFile() {
IndexFile indexFile = null;
for (int times = 0; null == indexFile && times < MAX_TRY_IDX_CREATE; times++) {
indexFile = this.getAndCreateLastIndexFile();
if (null != indexFile)
break;
try {
log.info("Tried to create index file " + times + " times");
Thread.sleep(1000);
} catch (InterruptedException e) {
log.error("Interrupted", e);
}
}
if (null == indexFile) {
this.defaultMessageStore.getAccessRights().makeIndexFileError();
log.error("Mark index file cannot build flag");
}
return indexFile;
}可以看到这个方法尝试多次(默认3次)调用getAndCreateLastIndexFile得到可以的indexFile。如果一次失败，等待1秒重试。若是都没得到、报错。
public IndexFile getAndCreateLastIndexFile() {
IndexFile indexFile = null;
IndexFile prevIndexFile = null;
long lastUpdateEndPhyOffset = 0;
long lastUpdateIndexTimestamp = 0;
{
this.readWriteLock.readLock().lock();
if (!this.indexFileList.isEmpty()) {
IndexFile tmp = this.indexFileList.get(this.indexFileList.size() - 1);
if (!tmp.isWriteFull()) {
indexFile = tmp;
} else {
lastUpdateEndPhyOffset = tmp.getEndPhyOffset();
lastUpdateIndexTimestamp = tmp.getEndTimestamp();
prevIndexFile = tmp;
}
}
this.readWriteLock.readLock().unlock();
}
if (indexFile == null) {
try {
String fileName =
this.storePath + File.separator
+ UtilAll.timeMillisToHumanString(System.currentTimeMillis());
indexFile =
new IndexFile(fileName, this.hashSlotNum, this.indexNum, lastUpdateEndPhyOffset,
lastUpdateIndexTimestamp);
this.readWriteLock.writeLock().lock();
this.indexFileList.add(indexFile);
} catch (Exception e) {
log.error("getLastIndexFile exception ", e);
} finally {
this.readWriteLock.writeLock().unlock();
}
if (indexFile != null) {
final IndexFile flushThisFile = prevIndexFile;
Thread flushThread = new Thread(new Runnable() {
@Override
public void run() {
IndexService.this.flush(flushThisFile);
}
}, "FlushIndexFileThread");
flushThread.setDaemon(true);
flushThread.start();
}
}
return indexFile;
}先加读锁，找到最后一个indexFile文件，看其是否满了，如果没满，那么返回该文件，否则重新创建新的indexFile文件，并且加写锁，将其新创建的indexFile加入到indexFileList方便管理，解锁。然后创建一个守护线程，负责把前一个indexFile文件刷新到硬盘中。
在得到了可写的indexFile之后，得到消息的topic跟keys，如果消息类型是TRANSACTION_ROLLBACK_TYPE那么到这里就直接返回了。先把消息的uniqKey进行putKey。我们先来看下什么是消息的key跟uinqKey
keys = propertiesMap.get(MessageConst.PROPERTY_KEYS);
uniqKey = propertiesMap.get(MessageConst.PROPERTY_UNIQ_CLIENT_MESSAGE_ID_KEYIDX);public static String createUniqID() {
StringBuilder sb = new StringBuilder(LEN * 2);
sb.append(FIX_STRING);
sb.append(UtilAll.bytes2string(createUniqIDBuffer()));
return sb.toString();
}
static {
LEN = 4 + 2 + 4 + 4 + 2;
ByteBuffer tempBuffer = ByteBuffer.allocate(10);
tempBuffer.position(2);
tempBuffer.putInt(UtilAll.getPid());
tempBuffer.position(0);
try {
tempBuffer.put(UtilAll.getIP());
} catch (Exception e) {
tempBuffer.put(createFakeIP());
}
tempBuffer.position(6);
tempBuffer.putInt(MessageClientIDSetter.class.getClassLoader().hashCode());
FIX_STRING = UtilAll.bytes2string(tempBuffer.array());
setStartTime(System.currentTimeMillis());
COUNTER = new AtomicInteger(0);
}
private static byte[] createUniqIDBuffer() {
ByteBuffer buffer = ByteBuffer.allocate(4 + 2);
long current = System.currentTimeMillis();
if (current >= nextStartTime) {
setStartTime(current);
}
buffer.position(0);
buffer.putInt((int) (System.currentTimeMillis() - startTime));
buffer.putShort((short) COUNTER.getAndIncrement());
return buffer.array();
}可以看到uniqKey的组成由FIX_STRING(10bit)+currentTime(4bit)+count(2bit)，FIX_STRING由ip、pid、classLoader的hashCode组成。整个用于标记消息的唯一性。
继续回到IndexServer的buildIndex()方法中。
private String buildKey(final String topic, final String key) {
return topic + "#" + key;
}buildKey无非在key之前加topic+"#"。
将uniqKey进行putKey
private IndexFile putKey(IndexFile indexFile, DispatchRequest msg, String idxKey) {
for (boolean ok = indexFile.putKey(idxKey, msg.getCommitLogOffset(), msg.getStoreTimestamp()); !ok; ) {
log.warn("Index file [" + indexFile.getFileName() + "] is full, trying to create another one");
indexFile = retryGetAndCreateIndexFile();
if (null == indexFile) {
return null;
}
ok = indexFile.putKey(idxKey, msg.getCommitLogOffset(), msg.getStoreTimestamp());
}
return indexFile;
} public boolean putKey(final String key, final long phyOffset, final long storeTimestamp) {
if (this.indexHeader.getIndexCount() < this.indexNum) {
int keyHash = indexKeyHashMethod(key);
int slotPos = keyHash % this.hashSlotNum;
int absSlotPos = IndexHeader.INDEX_HEADER_SIZE + slotPos * hashSlotSize;
FileLock fileLock = null;
try {
// fileLock = this.fileChannel.lock(absSlotPos, hashSlotSize,
// false);
int slotValue = this.mappedByteBuffer.getInt(absSlotPos);
if (slotValue <= invalidIndex || slotValue > this.indexHeader.getIndexCount()) {
slotValue = invalidIndex;
}
long timeDiff = storeTimestamp - this.indexHeader.getBeginTimestamp();
timeDiff = timeDiff / 1000;
if (this.indexHeader.getBeginTimestamp() <= 0) {
timeDiff = 0;
} else if (timeDiff > Integer.MAX_VALUE) {
timeDiff = Integer.MAX_VALUE;
} else if (timeDiff < 0) {
timeDiff = 0;
}
int absIndexPos =
IndexHeader.INDEX_HEADER_SIZE + this.hashSlotNum * hashSlotSize
+ this.indexHeader.getIndexCount() * indexSize;
this.mappedByteBuffer.putInt(absIndexPos, keyHash);
this.mappedByteBuffer.putLong(absIndexPos + 4, phyOffset);
this.mappedByteBuffer.putInt(absIndexPos + 4 + 8, (int) timeDiff);
this.mappedByteBuffer.putInt(absIndexPos + 4 + 8 + 4, slotValue);
this.mappedByteBuffer.putInt(absSlotPos, this.indexHeader.getIndexCount());
if (this.indexHeader.getIndexCount() <= 1) {
this.indexHeader.setBeginPhyOffset(phyOffset);
this.indexHeader.setBeginTimestamp(storeTimestamp);
}
this.indexHeader.incHashSlotCount();
this.indexHeader.incIndexCount();
this.indexHeader.setEndPhyOffset(phyOffset);
this.indexHeader.setEndTimestamp(storeTimestamp);
return true;
} catch (Exception e) {
log.error("putKey exception, Key: " + key + " KeyHashCode: " + key.hashCode(), e);
} finally {
if (fileLock != null) {
try {
fileLock.release();
} catch (IOException e) {
log.error("Failed to release the lock", e);
}
}
}
} else {
log.warn("Over index file capacity: index count = " + this.indexHeader.getIndexCount()
+ "; index max num = " + this.indexNum);
}
return false;
}如果目前index file存储的条目数小于允许的条目数，则存入当前文件中，如果超出，则返回false说明indexfile文件写满。得到key的hashCode再%hashSlotNum定位到key的相应hashSlot位置，再通过IndexHeader.INDEX_HEADER_SIZE + slotPos * hashSlotSize计算出其对应的bit位置。读取key所在hashslot下标处的值slotValue(4个字节)，如果小于0或超过当前包含的indexCount，则设置为0；计算消息的存储时间与当前IndexFile存放的最小时间差额timeDiff；然后根据当前存入的index的数目，计算出当前的index该存放的位置下标absIndexPos=IndexHeader.INDEX_HEADER_SIZE+this.hashSlotNum*hashSlotSize+ this.indexHeader.getIndexCount() * indexSize，其不过是indexHeadSize+hashSlotsSize+当前index偏移量。
然后在absIndexPos开始存入当前消息的数据，(KeyHash(4字节)、phyOffset(8字节)、时间差timeDiff(4字节)、slotValue(4个字节，这个表示key的相同hashCode的上一条消息的偏移量IndexCount))，然后在absSlotPos位置写下当前消息的IndexCount。最后更新IndexFile头部相关字段，比如最小时间，当前最大时间等。
然后遍历keys的每个key，调用putKey。此时保存到内存映射文件中，并没有执行刷盘操作。
整个流程到这里告一段落。
想必读putKey方法时，我们已经看出了indexFile的数据结构。
IndexFileHeader : beginTimestamp(8字节) + endTimestamp(8字节) + beginOffset(8字节) + endOffset(8字节) + hashCodeCount(4字节) + indexCount(4字节)
indexFile ： IndexFileHeader + 500W个HashSlot + N个Index(每个20字节)
我们看下从indexFile取数据操作
public void selectPhyOffset(final List<Long> phyOffsets, final String key, final int maxNum,
final long begin, final long end, boolean lock) {
if (this.mappedFile.hold()) {
int keyHash = indexKeyHashMethod(key);
int slotPos = keyHash % this.hashSlotNum;
int absSlotPos = IndexHeader.INDEX_HEADER_SIZE + slotPos * hashSlotSize;
FileLock fileLock = null;
try {
if (lock) {
// fileLock = this.fileChannel.lock(absSlotPos,
// hashSlotSize, true);
}
int slotValue = this.mappedByteBuffer.getInt(absSlotPos);
// if (fileLock != null) {
// fileLock.release();
// fileLock = null;
// }
if (slotValue <= invalidIndex || slotValue > this.indexHeader.getIndexCount()
|| this.indexHeader.getIndexCount() <= 1) {
} else {
for (int nextIndexToRead = slotValue; ; ) {
if (phyOffsets.size() >= maxNum) {
break;
}
int absIndexPos =
IndexHeader.INDEX_HEADER_SIZE + this.hashSlotNum * hashSlotSize
+ nextIndexToRead * indexSize;
int keyHashRead = this.mappedByteBuffer.getInt(absIndexPos);
long phyOffsetRead = this.mappedByteBuffer.getLong(absIndexPos + 4);
long timeDiff = (long) this.mappedByteBuffer.getInt(absIndexPos + 4 + 8);
int prevIndexRead = this.mappedByteBuffer.getInt(absIndexPos + 4 + 8 + 4);
if (timeDiff < 0) {
break;
}
timeDiff *= 1000L;
long timeRead = this.indexHeader.getBeginTimestamp() + timeDiff;
boolean timeMatched = (timeRead >= begin) && (timeRead <= end);
if (keyHash == keyHashRead && timeMatched) {
phyOffsets.add(phyOffsetRead);
}
if (prevIndexRead <= invalidIndex
|| prevIndexRead > this.indexHeader.getIndexCount()
|| prevIndexRead == nextIndexToRead || timeRead < begin) {
break;
}
nextIndexToRead = prevIndexRead;
}
}
} catch (Exception e) {
log.error("selectPhyOffset exception ", e);
} finally {
if (fileLock != null) {
try {
fileLock.release();
} catch (IOException e) {
log.error("Failed to release the lock", e);
}
}
this.mappedFile.release();
}
}
}运行过程中，消息从生产者客户端发来，broker接收后，消息发送到commitlog文件存储后，ReputMessageService线程会同步将消息转发到Logic消息队列（ConsumeQueue）、index文件(IndexFile)。形成索引，方便消费者查找。