C# .Net6 repository pattern performace impact on server resources-CodePudding

I would like to know what the performance difference is between these 2 ways of inserting data into a database.

The performance difference i am talking about is standard usage of server resources and not the speed at which data is inserted into the database.

In the first example i am adding a log into a database, but the object is first being set to a local variable.

public class LogService : ILogService
{
    private readonly IUnitOfWork _unitOfWork;
    private readonly IMapper _mapper;

    public LogService(IUnitOfWork unitOfWork, IMapper mapper)
    {
        _unitOfWork = unitOfWork;
        _mapper = mapper;
    }

    public async Task AddLog(LogViewModel data)
    {
        var log = _mapper.Map<Log>(data);

        _unitOfWork.Logs.Add(log);

        await _unitOfWork.Complete();
    }
}

in the second example the function does the same thing but does not make use of a local variable.

public class LogService : ILogService
{
    private readonly IUnitOfWork _unitOfWork;
    private readonly IMapper _mapper;

    public LogService(IUnitOfWork unitOfWork, IMapper mapper)
    {
        _unitOfWork = unitOfWork;
        _mapper = mapper;
    }

    public async Task AddLog(LogViewModel data)
    {
        _unitOfWork.Logs.Add(_mapper.Map<Log>(data));

        await _unitOfWork.Complete();
    }
}

I know that the second approach is less code, but is there an actual difference in resources that are being used by first declaring a local variable?

CodePudding user response：

Absolutely no difference. Zero. Nada. Even the generated byte code is probably 100% identical.

Local variables are pointers that exist on a stack. Arguments to method calls are points that are pushed to the stack. Notice the similarity?

If you think there is a difference, dump the byte code (of a release build, not a debug build) and compare it. If you still don't believe it, run a benchmark or profile your application.

What's more: the database access is thousands of times slower than doing anything in-memory (Latency Numbers Every Programmer Should Know):

L2 cache reference                           7   ns     14x L1 cache
Main memory reference                      100   ns
Round trip within same datacenter      500,000   ns     500 us