SOCI bulk insert using vector

I am trying to insert data into mysql 5.6 db, trying to follow soci doc's example3.

Following code move's portions of record_data vector to record_data_temp and inserts them into db

    std::vector<std::string> record_data_temp;
    soci::statement st = (sql_imei.prepare << "INSERT INTO list_of_record_data VALUES(:record_data, " << id << ")", soci::use(record_data_temp));

    std::vector<std::string> record_data;
    #if TESTING_FILLER
    for (unsigned long i = 0; i < SIZE_LIMIT; ++i)
            record_data.push_back(std::to_string(i));
    #endif

    int partCount = std::stoi(argv[1]);
    record_data_temp.resize(partCount);
    auto v1_begin = record_data.begin();
    auto v1_end = v1_begin + partCount;
    int i=0;
    while(i < record_data.size())
    {
            std::move(v1_begin, v1_end, record_data_temp.begin());
            // To prevent extra elements in last iteration
            if ((i + partCount) > record_data.size())
                    record_data_temp.resize(record_data.size() % partCount);
            i += partCount;
            v1_begin = v1_end;
            if ((i + partCount) > record_data.size())
                    v1_end += record_data.size() % partCount;
            else
                    v1_end += partCount;
            #if DISPLAY_VEC
            std::cout << "NEWt";
            for(auto& str:record_data_temp)
                    std::cout << str << "t";
            std::cout << std::endl;
            #endif
            st.execute(true);
            std::cout << "updated :" << st.get_affected_rows() << std::endl;
    }

for record_data with elements 0,1,2,3,4,5,6,7,8,9 with portion as 3 (partCount) my program outputs

    NEW     0       1       2
    updated :3
    NEW     3       4       5
    updated :3
    NEW     6       7       8
    updated :3
    NEW     9
    updated :0

But incorrectly inserts in database

    mysql> SELECT * FROM list_of_record_data;
    +--------+-----+
    | msisdn | id  |
    +--------+-----+
    | 0      | 123 |
    | 1      | 123 |
    | 2      | 123 |
    | 0      | 123 |
    | 1      | 123 |
    | 2      | 123 |
    | 0      | 123 |
    | 1      | 123 |
    | 2      | 123 |
    | 0      | 123 |
    +--------+-----+
    10 rows in set (0.00 sec)

Where am I going wrong? I am using g++ (GCC) 5.2.0 on Red Hat Enterprise Linux Server release 6.6 (Santiago). The test performed with dummy data, actual record_data vector size will be over 50 million. Thanks for any help.