Java Code Examples for org.apache.rocketmq.remoting.protocol.RemotingCommand#createResponseCommand()

private RemotingCommand getConsumerRunningInfo(ChannelHandlerContext ctx,
        RemotingCommand request) throws RemotingCommandException {
        final RemotingCommand response = RemotingCommand.createResponseCommand(null);
        final GetConsumerRunningInfoRequestHeader requestHeader =
            (GetConsumerRunningInfoRequestHeader) request.decodeCommandCustomHeader(GetConsumerRunningInfoRequestHeader.class);

//        获取消费者的运行信息=》
        ConsumerRunningInfo consumerRunningInfo = this.mqClientFactory.consumerRunningInfo(requestHeader.getConsumerGroup());
        if (null != consumerRunningInfo) {
            if (requestHeader.isJstackEnable()) {
                Map<Thread, StackTraceElement[]> map = Thread.getAllStackTraces();
//                获取所有的线程堆栈信息
                String jstack = UtilAll.jstack(map);
                consumerRunningInfo.setJstack(jstack);
            }

            response.setCode(ResponseCode.SUCCESS);
            response.setBody(consumerRunningInfo.encode());
        } else {
            response.setCode(ResponseCode.SYSTEM_ERROR);
            response.setRemark(String.format("The Consumer Group <%s> not exist in this consumer", requestHeader.getConsumerGroup()));
        }

        return response;
    }
 

private RemotingCommand getConsumerRunningInfo(ChannelHandlerContext ctx, RemotingCommand request) throws RemotingCommandException {
    final RemotingCommand response = RemotingCommand.createResponseCommand(null);
    final GetConsumerRunningInfoRequestHeader requestHeader =
        (GetConsumerRunningInfoRequestHeader) request.decodeCommandCustomHeader(GetConsumerRunningInfoRequestHeader.class);

    ConsumerRunningInfo consumerRunningInfo = this.mqClientFactory.consumerRunningInfo(requestHeader.getConsumerGroup());
    if (null != consumerRunningInfo) {
        if (requestHeader.isJstackEnable()) {
            Map<Thread, StackTraceElement[]> map = Thread.getAllStackTraces();
            String jstack = UtilAll.jstack(map);
            consumerRunningInfo.setJstack(jstack);
        }

        response.setCode(ResponseCode.SUCCESS);
        response.setBody(consumerRunningInfo.encode());
    } else {
        response.setCode(ResponseCode.SYSTEM_ERROR);
        response.setRemark(String.format("The Consumer Group <%s> not exist in this consumer", requestHeader.getConsumerGroup()));
    }

    return response;
}
 

private RemotingCommand lockBatchMQ(ChannelHandlerContext ctx, RemotingCommand request) throws RemotingCommandException {
    final RemotingCommand response = RemotingCommand.createResponseCommand(null);
    LockBatchRequestBody requestBody = LockBatchRequestBody.decode(request.getBody(), LockBatchRequestBody.class);

    Set<MessageQueue> lockOKMQSet = this.brokerController.getRebalanceLockManager().tryLockBatch(//
        requestBody.getConsumerGroup(), //
        requestBody.getMqSet(), //
        requestBody.getClientId());

    LockBatchResponseBody responseBody = new LockBatchResponseBody();
    responseBody.setLockOKMQSet(lockOKMQSet);

    response.setBody(responseBody.encode());
    response.setCode(ResponseCode.SUCCESS);
    response.setRemark(null);
    return response;
}
 

private RemotingCommand registerMessageFilterClass(ChannelHandlerContext ctx, RemotingCommand request) throws RemotingCommandException {
    final RemotingCommand response = RemotingCommand.createResponseCommand(null);
    final RegisterMessageFilterClassRequestHeader requestHeader =
        (RegisterMessageFilterClassRequestHeader) request.decodeCommandCustomHeader(RegisterMessageFilterClassRequestHeader.class);

    try {
        boolean ok = this.filtersrvController.getFilterClassManager().registerFilterClass(requestHeader.getConsumerGroup(),
            requestHeader.getTopic(),
            requestHeader.getClassName(),
            requestHeader.getClassCRC(),
            request.getBody());
        if (!ok) {
            throw new Exception("registerFilterClass error");
        }
    } catch (Exception e) {
        response.setCode(ResponseCode.SYSTEM_ERROR);
        response.setRemark(RemotingHelper.exceptionSimpleDesc(e));
        return response;
    }

    response.setCode(ResponseCode.SUCCESS);
    response.setRemark(null);
    return response;
}
 

private RemotingCommand getBrokerConfig(ChannelHandlerContext ctx, RemotingCommand request) {

        final RemotingCommand response = RemotingCommand.createResponseCommand(GetBrokerConfigResponseHeader.class);
        final GetBrokerConfigResponseHeader responseHeader = (GetBrokerConfigResponseHeader) response.readCustomHeader();

        String content = this.brokerController.getConfiguration().getAllConfigsFormatString();
        if (content != null && content.length() > 0) {
            try {
                response.setBody(content.getBytes(MixAll.DEFAULT_CHARSET));
            } catch (UnsupportedEncodingException e) {
                log.error("", e);

                response.setCode(ResponseCode.SYSTEM_ERROR);
                response.setRemark("UnsupportedEncodingException " + e);
                return response;
            }
        }

        responseHeader.setVersion(this.brokerController.getConfiguration().getDataVersionJson());

        response.setCode(ResponseCode.SUCCESS);
        response.setRemark(null);
        return response;
    }
 

private RemotingCommand searchOffsetByTimestamp(ChannelHandlerContext ctx, RemotingCommand request) throws RemotingCommandException {
    final RemotingCommand response = RemotingCommand.createResponseCommand(SearchOffsetResponseHeader.class);
    final SearchOffsetResponseHeader responseHeader = (SearchOffsetResponseHeader) response.readCustomHeader();
    final SearchOffsetRequestHeader requestHeader =
        (SearchOffsetRequestHeader) request.decodeCommandCustomHeader(SearchOffsetRequestHeader.class);

    long offset = this.brokerController.getMessageStore().getOffsetInQueueByTime(requestHeader.getTopic(), requestHeader.getQueueId(),
        requestHeader.getTimestamp());

    responseHeader.setOffset(offset);

    response.setCode(ResponseCode.SUCCESS);
    response.setRemark(null);
    return response;
}
 

private RemotingCommand unlockBatchMQ(ChannelHandlerContext ctx,
    RemotingCommand request) throws RemotingCommandException {
    final RemotingCommand response = RemotingCommand.createResponseCommand(null);
    UnlockBatchRequestBody requestBody = UnlockBatchRequestBody.decode(request.getBody(), UnlockBatchRequestBody.class);

    this.brokerController.getRebalanceLockManager().unlockBatch(
        requestBody.getConsumerGroup(),
        requestBody.getMqSet(),
        requestBody.getClientId());

    response.setCode(ResponseCode.SUCCESS);
    response.setRemark(null);
    return response;
}
 

private RemotingCommand resumeCheckHalfMessage(ChannelHandlerContext ctx,
    RemotingCommand request)
    throws RemotingCommandException {
    final ResumeCheckHalfMessageRequestHeader requestHeader = (ResumeCheckHalfMessageRequestHeader) request
        .decodeCommandCustomHeader(ResumeCheckHalfMessageRequestHeader.class);
    final RemotingCommand response = RemotingCommand.createResponseCommand(null);
    SelectMappedBufferResult selectMappedBufferResult = null;
    try {
        MessageId messageId = MessageDecoder.decodeMessageId(requestHeader.getMsgId());
        selectMappedBufferResult = this.brokerController.getMessageStore()
            .selectOneMessageByOffset(messageId.getOffset());
        MessageExt msg = MessageDecoder.decode(selectMappedBufferResult.getByteBuffer());
        msg.putUserProperty(MessageConst.PROPERTY_TRANSACTION_CHECK_TIMES, String.valueOf(0));
        PutMessageResult putMessageResult = this.brokerController.getMessageStore()
            .putMessage(toMessageExtBrokerInner(msg));
        if (putMessageResult != null
            && putMessageResult.getPutMessageStatus() == PutMessageStatus.PUT_OK) {
            log.info(
                "Put message back to RMQ_SYS_TRANS_HALF_TOPIC. real topic={}",
                msg.getUserProperty(MessageConst.PROPERTY_REAL_TOPIC));
            response.setCode(ResponseCode.SUCCESS);
            response.setRemark(null);
        } else {
            log.error("Put message back to RMQ_SYS_TRANS_HALF_TOPIC failed.");
            response.setCode(ResponseCode.SYSTEM_ERROR);
            response.setRemark("Put message back to RMQ_SYS_TRANS_HALF_TOPIC failed.");
        }
    } catch (Exception e) {
        log.error("Exception was thrown when putting message back to RMQ_SYS_TRANS_HALF_TOPIC.");
        response.setCode(ResponseCode.SYSTEM_ERROR);
        response.setRemark("Exception was thrown when putting message back to RMQ_SYS_TRANS_HALF_TOPIC.");
    } finally {
        if (selectMappedBufferResult != null) {
            selectMappedBufferResult.release();
        }
    }
    return response;
}
 

private RemotingCommand unlockBatchMQ(ChannelHandlerContext ctx,
    RemotingCommand request) throws RemotingCommandException {

    final RemotingCommand response = RemotingCommand.createResponseCommand(null);
    UnlockBatchRequestBody requestBody = UnlockBatchRequestBody.decode(request.getBody(), UnlockBatchRequestBody.class);

    this.brokerController.getRebalanceLockManager().unlockBatch(
        requestBody.getConsumerGroup(),
        requestBody.getMqSet(),
        requestBody.getClientId());

    response.setCode(ResponseCode.SUCCESS);
    response.setRemark(null);
    return response;
}
 

private RemotingCommand getTopicsByCluster(ChannelHandlerContext ctx,
    RemotingCommand request) throws RemotingCommandException {
    final RemotingCommand response = RemotingCommand.createResponseCommand(null);
    final GetTopicsByClusterRequestHeader requestHeader =
        (GetTopicsByClusterRequestHeader) request.decodeCommandCustomHeader(GetTopicsByClusterRequestHeader.class);

    byte[] body = this.namesrvController.getRouteInfoManager().getTopicsByCluster(requestHeader.getCluster());

    response.setBody(body);
    response.setCode(ResponseCode.SUCCESS);
    response.setRemark(null);
    return response;
}
 

private RemotingCommand checkPrepareMessage(MessageExt msgExt, EndTransactionRequestHeader requestHeader) {
    final RemotingCommand response = RemotingCommand.createResponseCommand(null);
    if (msgExt != null) {
        final String pgroupRead = msgExt.getProperty(MessageConst.PROPERTY_PRODUCER_GROUP);
        if (!pgroupRead.equals(requestHeader.getProducerGroup())) {
            response.setCode(ResponseCode.SYSTEM_ERROR);
            response.setRemark("The producer group wrong");
            return response;
        }

        if (msgExt.getQueueOffset() != requestHeader.getTranStateTableOffset()) {
            response.setCode(ResponseCode.SYSTEM_ERROR);
            response.setRemark("The transaction state table offset wrong");
            return response;
        }

        if (msgExt.getCommitLogOffset() != requestHeader.getCommitLogOffset()) {
            response.setCode(ResponseCode.SYSTEM_ERROR);
            response.setRemark("The commit log offset wrong");
            return response;
        }
    } else {
        response.setCode(ResponseCode.SYSTEM_ERROR);
        response.setRemark("Find prepared transaction message failed");
        return response;
    }
    response.setCode(ResponseCode.SUCCESS);
    return response;
}
 

private RemotingCommand getBrokerClusterInfo(ChannelHandlerContext ctx, RemotingCommand request) {
    final RemotingCommand response = RemotingCommand.createResponseCommand(null);

    byte[] content = this.namesrvController.getRouteInfoManager().getAllClusterInfo();
    response.setBody(content);

    response.setCode(ResponseCode.SUCCESS);
    response.setRemark(null);
    return response;
}
 

/**
 * Producer第一次发送时或者是每隔30S轮询
 * 获取指定Topic的TopicRouteData
 *
 * @param ctx
 * @param request
 * @return
 * @throws RemotingCommandException
 */
public RemotingCommand getRouteInfoByTopic(ChannelHandlerContext ctx, RemotingCommand request) throws RemotingCommandException {
    final RemotingCommand response = RemotingCommand.createResponseCommand(null);
    final GetRouteInfoRequestHeader requestHeader =
        (GetRouteInfoRequestHeader)request.decodeCommandCustomHeader(GetRouteInfoRequestHeader.class);

    TopicRouteData topicRouteData = this.namesrvController.getRouteInfoManager().pickupTopicRouteData(requestHeader.getTopic());

    if (topicRouteData != null) {
        if (this.namesrvController.getNamesrvConfig().isOrderMessageEnable()) {
            String orderTopicConf =
                this.namesrvController.getKvConfigManager().getKVConfig(NamesrvUtil.NAMESPACE_ORDER_TOPIC_CONFIG,
                    requestHeader.getTopic());
            topicRouteData.setOrderTopicConf(orderTopicConf);
        }

        byte[] content = topicRouteData.encode();
        response.setBody(content);
        response.setCode(ResponseCode.SUCCESS);
        response.setRemark(null);
        return response;
    }

    response.setCode(ResponseCode.TOPIC_NOT_EXIST);
    response.setRemark("No topic route info in name server for the topic: " + requestHeader.getTopic()
        + FAQUrl.suggestTodo(FAQUrl.APPLY_TOPIC_URL));
    return response;
}
 

private RemotingCommand getHasUnitSubTopicList(ChannelHandlerContext ctx,
    RemotingCommand request) throws RemotingCommandException {
    final RemotingCommand response = RemotingCommand.createResponseCommand(null);

    byte[] body = this.namesrvController.getRouteInfoManager().getHasUnitSubTopicList();

    response.setBody(body);
    response.setCode(ResponseCode.SUCCESS);
    response.setRemark(null);
    return response;
}
 

@Override
public RemotingCommand getRouteInfoByTopic(ChannelHandlerContext ctx,
    RemotingCommand request) throws RemotingCommandException {
    final RemotingCommand response = RemotingCommand.createResponseCommand(null);
    final GetRouteInfoRequestHeader requestHeader =
        (GetRouteInfoRequestHeader) request.decodeCommandCustomHeader(GetRouteInfoRequestHeader.class);

    TopicRouteData topicRouteData = this.namesrvController.getRouteInfoManager().pickupTopicRouteData(requestHeader.getTopic());
    if (topicRouteData != null) {
        String orderTopicConf =
            this.namesrvController.getKvConfigManager().getKVConfig(NamesrvUtil.NAMESPACE_ORDER_TOPIC_CONFIG,
                requestHeader.getTopic());
        topicRouteData.setOrderTopicConf(orderTopicConf);
    } else {
        try {
            topicRouteData = adminExt.examineTopicRouteInfo(requestHeader.getTopic());
        } catch (Exception e) {
            log.info("get route info by topic from product environment failed. envName={},", productEnvName);
        }
    }

    if (topicRouteData != null) {
        byte[] content = topicRouteData.encode();
        response.setBody(content);
        response.setCode(ResponseCode.SUCCESS);
        response.setRemark(null);
        return response;
    }

    response.setCode(ResponseCode.TOPIC_NOT_EXIST);
    response.setRemark("No topic route info in name server for the topic: " + requestHeader.getTopic()
        + FAQUrl.suggestTodo(FAQUrl.APPLY_TOPIC_URL));
    return response;
}
 

/**
 * 发送最终的消息,就是把成功的消息发送原本属于他的topic和队列里
 * @param msgInner ;
 * @return ;
 */
private RemotingCommand sendFinalMessage(MessageExtBrokerInner msgInner) {

    final RemotingCommand response = RemotingCommand.createResponseCommand(null);
    final PutMessageResult putMessageResult = this.brokerController.getMessageStore().putMessage(msgInner);
    if (putMessageResult != null) {
        switch (putMessageResult.getPutMessageStatus()) {
            // Success
            case PUT_OK:
            case FLUSH_DISK_TIMEOUT:
            case FLUSH_SLAVE_TIMEOUT:
            case SLAVE_NOT_AVAILABLE:
                response.setCode(ResponseCode.SUCCESS);
                response.setRemark(null);
                break;
            // Failed
            case CREATE_MAPEDFILE_FAILED:
                response.setCode(ResponseCode.SYSTEM_ERROR);
                response.setRemark("Create mapped file failed.");
                break;
            case MESSAGE_ILLEGAL:
            case PROPERTIES_SIZE_EXCEEDED:
                response.setCode(ResponseCode.MESSAGE_ILLEGAL);
                response.setRemark("The message is illegal, maybe msg body or properties length not matched. msg body length limit 128k, msg properties length limit 32k.");
                break;
            case SERVICE_NOT_AVAILABLE:
                response.setCode(ResponseCode.SERVICE_NOT_AVAILABLE);
                response.setRemark("Service not available now.");
                break;
            case OS_PAGECACHE_BUSY:
                response.setCode(ResponseCode.SYSTEM_ERROR);
                response.setRemark("OS page cache busy, please try another machine");
                break;
            case UNKNOWN_ERROR:
                response.setCode(ResponseCode.SYSTEM_ERROR);
                response.setRemark("UNKNOWN_ERROR");
                break;
            default:
                response.setCode(ResponseCode.SYSTEM_ERROR);
                response.setRemark("UNKNOWN_ERROR DEFAULT");
                break;
        }
        return response;
    } else {
        response.setCode(ResponseCode.SYSTEM_ERROR);
        response.setRemark("store putMessage return null");
    }
    return response;
}
 

/**
 * 更新或者创建topic
 * @param ctx ;
 * @param request ;
 * @return ;
 * @throws RemotingCommandException ;
 */
private synchronized RemotingCommand updateAndCreateTopic(ChannelHandlerContext ctx,
    RemotingCommand request) throws RemotingCommandException {

    final RemotingCommand response = RemotingCommand.createResponseCommand(null);
    final CreateTopicRequestHeader requestHeader =
        (CreateTopicRequestHeader) request.decodeCommandCustomHeader(CreateTopicRequestHeader.class);

    log.info("updateAndCreateTopic called by {}", RemotingHelper.parseChannelRemoteAddr(ctx.channel()));

    //和系统topic冲突。BrokerClusterName
    if (requestHeader.getTopic().equals(this.brokerController.getBrokerConfig().getBrokerClusterName())) {
        String errorMsg = "the topic[" + requestHeader.getTopic() + "] is conflict with system reserved words.";
        log.warn(errorMsg);
        response.setCode(ResponseCode.SYSTEM_ERROR);
        response.setRemark(errorMsg);
        return response;
    }

    try {
        response.setCode(ResponseCode.SUCCESS);
        response.setOpaque(request.getOpaque());
        response.markResponseType();
        response.setRemark(null);
        ctx.writeAndFlush(response);
    } catch (Exception e) {
        log.error("Failed to produce a proper response", e);
    }

    TopicConfig topicConfig = new TopicConfig(requestHeader.getTopic());
    topicConfig.setReadQueueNums(requestHeader.getReadQueueNums());
    topicConfig.setWriteQueueNums(requestHeader.getWriteQueueNums());
    topicConfig.setTopicFilterType(requestHeader.getTopicFilterTypeEnum());
    topicConfig.setPerm(requestHeader.getPerm());
    topicConfig.setTopicSysFlag(requestHeader.getTopicSysFlag() == null ? 0 : requestHeader.getTopicSysFlag());

    this.brokerController.getTopicConfigManager().updateTopicConfig(topicConfig);

    this.brokerController.registerIncrementBrokerData(topicConfig,this.brokerController.getTopicConfigManager().getDataVersion());

    return null;
}
 

/**
 * 查询消费者偏移量
 * @param ctx ctx
 * @param request request
 * @return ;
 * @throws RemotingCommandException ;
 */
private RemotingCommand queryConsumerOffset(ChannelHandlerContext ctx, RemotingCommand request)
    throws RemotingCommandException {

    final RemotingCommand response =
        RemotingCommand.createResponseCommand(QueryConsumerOffsetResponseHeader.class);

    final QueryConsumerOffsetResponseHeader responseHeader =
        (QueryConsumerOffsetResponseHeader) response.readCustomHeader();
    final QueryConsumerOffsetRequestHeader requestHeader =
        (QueryConsumerOffsetRequestHeader) request
            .decodeCommandCustomHeader(QueryConsumerOffsetRequestHeader.class);

    long offset =
        this.brokerController.getConsumerOffsetManager().queryOffset(
            requestHeader.getConsumerGroup(), requestHeader.getTopic(), requestHeader.getQueueId());

    //大于0直接返回
    if (offset >= 0) {
        responseHeader.setOffset(offset);
        response.setCode(ResponseCode.SUCCESS);
        response.setRemark(null);
    } else {
        //最小的偏移量从getMinOffsetInQueue取
        long minOffset =
            this.brokerController.getMessageStore().getMinOffsetInQueue(requestHeader.getTopic(),
                requestHeader.getQueueId());
        //如果minOffset小于0并且内存里也查不到
        if (minOffset <= 0
            && !this.brokerController.getMessageStore().checkInDiskByConsumeOffset(
            requestHeader.getTopic(), requestHeader.getQueueId(), 0)) {

            responseHeader.setOffset(0L);
            response.setCode(ResponseCode.SUCCESS);
            response.setRemark(null);
        } else {
            response.setCode(ResponseCode.QUERY_NOT_FOUND);
            response.setRemark("Not found, V3_0_6_SNAPSHOT maybe this group consumer boot first");
        }
    }

    return response;
}
 

private RemotingCommand queryConsumeTimeSpan(ChannelHandlerContext ctx,
    RemotingCommand request) throws RemotingCommandException {
    final RemotingCommand response = RemotingCommand.createResponseCommand(null);
    QueryConsumeTimeSpanRequestHeader requestHeader =
        (QueryConsumeTimeSpanRequestHeader) request.decodeCommandCustomHeader(QueryConsumeTimeSpanRequestHeader.class);

    final String topic = requestHeader.getTopic();
    TopicConfig topicConfig = this.brokerController.getTopicConfigManager().selectTopicConfig(topic);
    if (null == topicConfig) {
        response.setCode(ResponseCode.TOPIC_NOT_EXIST);
        response.setRemark("topic[" + topic + "] not exist");
        return response;
    }

    List<QueueTimeSpan> timeSpanSet = new ArrayList<QueueTimeSpan>();
    for (int i = 0; i < topicConfig.getWriteQueueNums(); i++) {
        QueueTimeSpan timeSpan = new QueueTimeSpan();
        MessageQueue mq = new MessageQueue();
        mq.setTopic(topic);
        mq.setBrokerName(this.brokerController.getBrokerConfig().getBrokerName());
        mq.setQueueId(i);
        timeSpan.setMessageQueue(mq);

        long minTime = this.brokerController.getMessageStore().getEarliestMessageTime(topic, i);
        timeSpan.setMinTimeStamp(minTime);

        long max = this.brokerController.getMessageStore().getMaxOffsetInQueue(topic, i);
        long maxTime = this.brokerController.getMessageStore().getMessageStoreTimeStamp(topic, i, max - 1);
        timeSpan.setMaxTimeStamp(maxTime);

        long consumeTime;
        long consumerOffset = this.brokerController.getConsumerOffsetManager().queryOffset(
            requestHeader.getGroup(), topic, i);
        if (consumerOffset > 0) {
            consumeTime = this.brokerController.getMessageStore().getMessageStoreTimeStamp(topic, i, consumerOffset - 1);
        } else {
            consumeTime = minTime;
        }
        timeSpan.setConsumeTimeStamp(consumeTime);

        long maxBrokerOffset = this.brokerController.getMessageStore().getMaxOffsetInQueue(requestHeader.getTopic(), i);
        if (consumerOffset < maxBrokerOffset) {
            long nextTime = this.brokerController.getMessageStore().getMessageStoreTimeStamp(topic, i, consumerOffset);
            timeSpan.setDelayTime(System.currentTimeMillis() - nextTime);
        }
        timeSpanSet.add(timeSpan);
    }

    QueryConsumeTimeSpanBody queryConsumeTimeSpanBody = new QueryConsumeTimeSpanBody();
    queryConsumeTimeSpanBody.setConsumeTimeSpanSet(timeSpanSet);
    response.setBody(queryConsumeTimeSpanBody.encode());
    response.setCode(ResponseCode.SUCCESS);
    response.setRemark(null);
    return response;
}
 

public RemotingCommand viewMessageById(ChannelHandlerContext ctx, RemotingCommand request)
        throws RemotingCommandException {
        final RemotingCommand response = RemotingCommand.createResponseCommand(null);
        final ViewMessageRequestHeader requestHeader =
            (ViewMessageRequestHeader) request.decodeCommandCustomHeader(ViewMessageRequestHeader.class);

        response.setOpaque(request.getOpaque());

//        按offste查询消息=》
        final SelectMappedBufferResult selectMappedBufferResult =
            this.brokerController.getMessageStore().selectOneMessageByOffset(requestHeader.getOffset());
        if (selectMappedBufferResult != null) {
            response.setCode(ResponseCode.SUCCESS);
            response.setRemark(null);

            try {
                FileRegion fileRegion =
                    new OneMessageTransfer(response.encodeHeader(selectMappedBufferResult.getSize()),
                        selectMappedBufferResult);
                ctx.channel().writeAndFlush(fileRegion).addListener(new ChannelFutureListener() {
                    @Override
                    public void operationComplete(ChannelFuture future) throws Exception {
                        selectMappedBufferResult.release();
                        if (!future.isSuccess()) {
                            log.error("Transfer one message from page cache failed, ", future.cause());
                        }
                    }
                });
            } catch (Throwable e) {
                log.error("", e);
                selectMappedBufferResult.release();
            }

            return null;
        } else {
            response.setCode(ResponseCode.SYSTEM_ERROR);
            response.setRemark("can not find message by the offset, " + requestHeader.getOffset());
        }

        return response;
    }