Question

I have a poco that needs to be mapped to another poco in a high traffic system. I intend to map these objects together in a simple mapper similar to this:

public class a 
{
    public int MyValue { get;set; }
    public string YAV { get; set; }
}

public class B
{
    public int aTestValue { get;set; }
    public string YetAnotherValue { get; set; }
}

public class Mapper 
{
    public static B MapIt(A a)
    {
        return new B { aTestValue = a.MyValue, YetAnotherValue = a.YAV };
    }
}

How much does a mapping like this really affect performance? Ignore the fact that we’ll have to write a mapping for all our types and just focus on the performance lost doing the actual mapping.

Answer 1

From our experience, the overhead won’t be much. I tested this recently by retrieving 75,000 rows of data using Linq to SQL and then mapping the L2S entities to POCO entities using mapping code we wrote. The cost of doing this was amazing small. If I recall correctly, it was something like 75 to 100 Ms to map 75K rows.