将二进制存档反序列化为std :: map时，为什么会出现空间开销

this is my program:

这是我的计划：

void loadB(map<unsigned int,myParam> & myParams)
{
    std::ifstream ifs("/tmp/all_params", std::ios::in | std::ios::binary);
    if( ifs.good() ){
        try{
            boost::archive::binary_iarchive ia(ifs);
            ia >> myParams;

            ifs.close();
        }catch(boost::archive::archive_exception& ex){
            syslog(LOG_NOTICE, "Archive Exception during deserializing params");
        }
    }else{  }
}
void loadB(map<