Performance difference between v1.8.3 and v1.9.1 about expressmapper HOT 2 OPEN

They aren't strictly like-for-like, take for example ExpressMapper vs AutoMapper; the AutoMapper registration is cfg.CreateMap<Foo, Foo>() whereas the ExpressMapper registration uses custom Member mappings e.g. .Member(foo => foo.Foos, foo => foo.Foos != null ? foo.Foos.Map<List<Foo>, List<Foo>>() : new List<Foo>()).

I tried running the tests and do get very high times for ExpressMapperComplexTypeMapper & ExpressMapperDeepMapper, however when removing the custom member mappings to make it a fair test with the others (and removing the assertions) I get the following results.

AutoMapperComplexTypeMapper 9.8261461
ExpressMapperComplexTypeMapper 143.674907

AutoMapperDeepMapper 1.4314013
ExpressMapperDeepMapper 133.096825

With custom member mappings removed:

AutoMapperComplexTypeMapper 10.4125455
ExpressMapperComplexTypeMapper 6.3748084

AutoMapperDeepMapper 1.3606325
ExpressMapperDeepMapper 1.9715963

It seems there is a performance issue but it looks isolated to custom member mappings.

from expressmapper.

Hi!

Thanks for the info!

I added the collection member mappings to create empty collections instead of leaving the properties null. For example in the Deep mapper test, if I map new Customer { Name = "Steve" } to a CustomerDto, the result object's Addresses and AddressesArray are both null with ExpressMapper, but populated with empty collections with AutoMapper and AgileMapper.

I may well have not done it in the best way - is there a better way you can suggest?

Cheers,

Steve

from expressmapper.