同时，还会将消息原来要发送到的目标Topic和队列信息存储到消息的属性中。相关源码如下所示：

org.apache.rocketmq.store.CommitLog#asyncPutMessage

public CompletableFuture<PutMessageResult> asyncPutMessage(final MessageExtBrokerInner msg) {
    // Set the storage time
    msg.setStoreTimestamp(System.currentTimeMillis());
    // Set the message body BODY CRC (consider the most appropriate setting
    // on the client)
    msg.setBodyCRC(UtilAll.crc32(msg.getBody()));
    // Back to Results
    AppendMessageResult result = null;

    StoreStatsService storeStatsService = this.defaultMessageStore.getStoreStatsService();

    String topic = msg.getTopic();
    int queueId = msg.getQueueId();

    final int tranType = MessageSysFlag.getTransactionValue(msg.getSysFlag());
    if (tranType == MessageSysFlag.TRANSACTION_NOT_TYPE
            || tranType == MessageSysFlag.TRANSACTION_COMMIT_TYPE) {
        // Delay Delivery
        if (msg.getDelayTimeLevel() > 0) {
            if (msg.getDelayTimeLevel() > this.defaultMessageStore.getScheduleMessageService().getMaxDelayLevel()) {
                msg.setDelayTimeLevel(this.defaultMessageStore.getScheduleMessageService().getMaxDelayLevel());
            }

            topic = TopicValidator.RMQ_SYS_SCHEDULE_TOPIC;
            queueId = ScheduleMessageService.delayLevel2QueueId(msg.getDelayTimeLevel());

            // Backup real topic, queueId
            MessageAccessor.putProperty(msg, MessageConst.PROPERTY_REAL_TOPIC, msg.getTopic());
            MessageAccessor.putProperty(msg, MessageConst.PROPERTY_REAL_QUEUE_ID, String.valueOf(msg.getQueueId()));
            msg.setPropertiesString(MessageDecoder.messageProperties2String(msg.getProperties()));

            msg.setTopic(topic);
            msg.setQueueId(queueId);
        }
    }

    InetSocketAddress bornSocketAddress = (InetSocketAddress) msg.getBornHost();
    if (bornSocketAddress.getAddress() instanceof Inet6Address) {
        msg.setBornHostV6Flag();
    }

    InetSocketAddress storeSocketAddress = (InetSocketAddress) msg.getStoreHost();
    if (storeSocketAddress.getAddress() instanceof Inet6Address) {
        msg.setStoreHostAddressV6Flag();
    }

    PutMessageThreadLocal putMessageThreadLocal = this.putMessageThreadLocal.get();
    PutMessageResult encodeResult = putMessageThreadLocal.getEncoder().encode(msg);
    if (encodeResult != null) {
        return CompletableFuture.completedFuture(encodeResult);
    }
    msg.setEncodedBuff(putMessageThreadLocal.getEncoder().encoderBuffer);
    PutMessageContext putMessageContext = new PutMessageContext(generateKey(putMessageThreadLocal.getKeyBuilder(), msg));

    long elapsedTimeInLock = 0;
    MappedFile unlockMappedFile = null;

    putMessageLock.lock(); //spin or ReentrantLock ,depending on store config
    try {
        MappedFile mappedFile = this.mappedFileQueue.getLastMappedFile();
        long beginLockTimestamp = this.defaultMessageStore.getSystemClock().now();
        this.beginTimeInLock = beginLockTimestamp;

        // Here settings are stored timestamp, in order to ensure an orderly
        // global
        msg.setStoreTimestamp(beginLockTimestamp);

        if (null == mappedFile || mappedFile.isFull()) {
            mappedFile = this.mappedFileQueue.getLastMappedFile(0); // Mark: NewFile may be cause noise
        }
        if (null == mappedFile) {
            log.error("create mapped file1 error, topic: " + msg.getTopic() + " clientAddr: " + msg.getBornHostString());
            beginTimeInLock = 0;
            return CompletableFuture.completedFuture(new PutMessageResult(PutMessageStatus.CREATE_MAPEDFILE_FAILED, null));
        }

        result = mappedFile.appendMessage(msg, this.appendMessageCallback, putMessageContext);
        switch (result.getStatus()) {
            case PUT_OK:
                break;
            case END_OF_FILE:
                unlockMappedFile = mappedFile;
                // Create a new file, re-write the message
                mappedFile = this.mappedFileQueue.getLastMappedFile(0);
                if (null == mappedFile) {
                    // XXX: warn and notify me
                    log.error("create mapped file2 error, topic: " + msg.getTopic() + " clientAddr: " + msg.getBornHostString());
                    beginTimeInLock = 0;
                    return CompletableFuture.completedFuture(new PutMessageResult(PutMessageStatus.CREATE_MAPEDFILE_FAILED, result));
                }
                result = mappedFile.appendMessage(msg, this.appendMessageCallback, putMessageContext);
                break;
            case MESSAGE_SIZE_EXCEEDED:
            case PROPERTIES_SIZE_EXCEEDED:
                beginTimeInLock = 0;
                return CompletableFuture.completedFuture(new PutMessageResult(PutMessageStatus.MESSAGE_ILLEGAL, result));
            case UNKNOWN_ERROR:
                beginTimeInLock = 0;
                return CompletableFuture.completedFuture(new PutMessageResult(PutMessageStatus.UNKNOWN_ERROR, result));
            default:
                beginTimeInLock = 0;
                return CompletableFuture.completedFuture(new PutMessageResult(PutMessageStatus.UNKNOWN_ERROR, result));
        }

        elapsedTimeInLock = this.defaultMessageStore.getSystemClock().now() - beginLockTimestamp;
        beginTimeInLock = 0;
    } finally {
        putMessageLock.unlock();
    }

    if (elapsedTimeInLock > 500) {
        log.warn("[NOTIFYME]putMessage in lock cost time(ms)={}, bodyLength={} AppendMessageResult={}", elapsedTimeInLock, msg.getBody().length, result);
    }

    if (null != unlockMappedFile && this.defaultMessageStore.getMessageStoreConfig().isWarmMapedFileEnable()) {
        this.defaultMessageStore.unlockMappedFile(unlockMappedFile);
    }

    PutMessageResult putMessageResult = new PutMessageResult(PutMessageStatus.PUT_OK, result);

    // Statistics
    storeStatsService.getSinglePutMessageTopicTimesTotal(msg.getTopic()).add(1);
    storeStatsService.getSinglePutMessageTopicSizeTotal(topic).add(result.getWroteBytes());

    CompletableFuture<PutMessageStatus> flushResultFuture = submitFlushRequest(result, msg);
    CompletableFuture<PutMessageStatus> replicaResultFuture = submitReplicaRequest(result, msg);
    return flushResultFuture.thenCombine(replicaResultFuture, (flushStatus, replicaStatus) -> {
        if (flushStatus != PutMessageStatus.PUT_OK) {
            putMessageResult.setPutMessageStatus(flushStatus);
        }
        if (replicaStatus != PutMessageStatus.PUT_OK) {
            putMessageResult.setPutMessageStatus(replicaStatus);
            if (replicaStatus == PutMessageStatus.FLUSH_SLAVE_TIMEOUT) {
                log.error("do sync transfer other node, wait return, but failed, topic: {} tags: {} client address: {}",
                        msg.getTopic(), msg.getTags(), msg.getBornHostNameString());
            }
        }
        return putMessageResult;
    });
}