您可以使用开源C++ CSV解析器库rapidCsv读取文件，然后使用MultithreadedTableWriter将数据写入分区表。下面是一个例子：

#include "MultithreadedTableWriter.h"
#include "DolphinDB.h"
#include "Util.h"
#include "rapidcsv.h"
#include <string>
#include <vector>
#include <thread>

using namespace std;
using namespace dolphindb;

Constant *createDateTime(string str) {
    int year, month, day, hour, minute, second;
    year = atoi(str.substr(0, 4).c_str());
    month = atoi(str.substr(5, 2).c_str());
    day = atoi(str.substr(8, 2).c_str());
    hour = atoi(str.substr(11, 2).c_str());
    minute = atoi(str.substr(14, 2).c_str());
    second = atoi(str.substr(17, 2).c_str());
    return Util::createDateTime(year, month, day, hour, minute, second);
}

int main(int argc, char *argv[]) {
    DBConnection::initialize();
    DBConnection conn;
    string host = "127.0.0.1";
    int port = 8848;
    string userId = "admin";
    string password = "123456";

    string path = "d:/data/devices_big/devices_big_readings.csv";

    try {
        vector<COMPRESS_METHOD> compress;
        compress.push_back(COMPRESS_DELTA);
        compress.push_back(COMPRESS_LZ4);
        compress.push_back(COMPRESS_DELTA);
        compress.push_back(COMPRESS_LZ4);
        compress.push_back(COMPRESS_LZ4);
        compress.push_back(COMPRESS_LZ4);
        compress.push_back(COMPRESS_LZ4);
        compress.push_back(COMPRESS_LZ4);
        compress.push_back(COMPRESS_LZ4);
        compress.push_back(COMPRESS_DELTA);
        compress.push_back(COMPRESS_DELTA);
        compress.push_back(COMPRESS_LZ4);
        compress.push_back(COMPRESS_LZ4);

        MultithreadedTableWriter writer("127.0.0.1", 8848, "admin", "123456", "dfs://iot", "readings",
            false, false, NULL, 10000, 1, 10, "device_id", &compress);

        rapidcsv::Document doc(path, rapidcsv::LabelParams(-1, -1));
        std::vector<string> time = doc.GetColumn<string>(0);
        std::vector<string> device_id = doc.GetColumn<string>(1);
        std::vector<int> battery_level = doc.GetColumn<int>(2);
        std::vector<string> battery_status = doc.GetColumn<string>(3);
        std::vector<double> battery_temperature = doc.GetColumn<double>(4);
        std::vector<string> bssid = doc.GetColumn<string>(5);
        std::vector<double> cpu_avg_1min = doc.GetColumn<double>(6);
        std::vector<double> cpu_avg_5min = doc.GetColumn<double>(7);
        std::vector<double> cpu_avg_15min = doc.GetColumn<double>(8);
        std::vector<long long> mem_free = doc.GetColumn<long long>(9);
        std::vector<long long> mem_used = doc.GetColumn<long long>(10);
        std::vector<int> rssi = doc.GetColumn<int>(11);
        std::vector<string> ssid = doc.GetColumn<string>(12);

        int rowNum = time.size();

        ErrorCodeInfo errorInfo;

        long long startTime = Util::getEpochTime();
        
        for (int i = 0; i < rowNum; i++) {
            if (writer.insert(errorInfo, 
                createDateTime(time[i]),
                device_id[i],
                battery_level[i],
                battery_status[i],
                battery_temperature[i],
                bssid[i],
                cpu_avg_1min[i],
                cpu_avg_5min[i],
                cpu_avg_15min[i],
                mem_free[i],
                mem_used[i],
                (short)rssi[i],
                ssid[i]
                ) == false) {
                //This part will not be executed.
                cout << "insert failed: " << errorInfo.errorInfo << endl;
                break;
            }
                
        }
        // Check the current status of MTW
        MultithreadedTableWriter::Status status;
        writer.getStatus(status);
        if (status.hasError()) {
            cout << "error in writing: " << status.errorInfo << endl;
        }
        writer.waitForThreadCompletion();
        // Check whether the tasks have been completed
        writer.getStatus(status);
        if (status.hasError()) {
            cout << "error after write complete: " << status.errorInfo << endl;
            // Obtain unwritten data
            std::vector<std::vector<ConstantSP>*> unwrittenData;
            writer.getUnwrittenData(unwrittenData);
            cout << "unwriterdata length " << unwrittenData.size() << endl;
        }
                     
        cout << "Insert Time " << Util::getEpochTime() - startTime << " ms" << endl;
        //Check the final result
        cout << conn.run("select count(*) from pt")->getString() << endl;

    }
    catch (std::exception &e) {
        cerr << "Failed to insert table, with exception: " << e.what() << endl;
    }
}