I have a blocking time in the automapper ProjectTo in .NET Framework App

[KanAtGodo]

I have some mysterious blocking time apparently in the mapper's ProjectTo method which I can't reproduce locally (probably because of the load). It works fine but after a while (random) response time and thread count spike.

Web App is in .NET Framework 4.8 and Automapper version is 10.1.1

This is what I saw in the profiler:

Mapping in question is very simple:

items = context.Extras .Where(r => ...) .ProjectTo<ExtraDTO>(mapper.ConfigurationProvider, x => x.VehicleExtra) .ToList();

And mapping definition:

CreateMap<Extra, ExtraDTO>() .ForMember(dest => dest.VehicleRental, opt => opt.Ignore()) .ForMember(dest => dest.VehicleExtra, opt => opt.ExplicitExpansion());

What caught my eye is that this is called in a loop for the problematic requests, maybe around 100 times or so. I know that this should be refactored so I have one call, but this block never happened before and this was not changed.

Any ideas why this might be happening? We are using Automapper for a while and this never happened.

[lbargaoanu]

You need an SQL profiler.

[KanAtGodo]

Can you elaborate a bit more plese? Why is there a block on accessing ConcurrentDictionary when Automapper does GetMapExpression if there is a database issue?

[lbargaoanu]

A repro would help. Make a gist that we can execute and see fail.

[lbargaoanu]

Probably unrelated, but check this https://github.com/AutoMapper/AutoMapper/pull/3473/files#r658618557.

[KanAtGodo]

Thanks a lot! We actually do have an inheritance between these models. Do you know if this is also the case in the lower versions of the Automapper, we were using v7 before this?

[lbargaoanu]

No, just AM 10.1.1., but it seems to me you have no idea what the problem actually is :) So, I'd check the SQL if I were you.