.NET Entity Framework Core 3.1 - Nlog leaking memory when :format=# when calling update on a big model and a db error occurs - entity-framework

Question

Happens in the save below:
context.Update(myBigObject);
await context.SaveChangesAsync(); -> Hangs here and RAM goes up until all the memory is finished
It only happens when a db error occurs ("String or binary data would be truncated" to be exact, meaning trying to stuff too large string in a field that's too small).
It happens when nlog config is:
${exception:format=#}
One "fix" is to change it to:
${exception:format=toString} -> But then I lose all the inner exception logging
See nlog docs on the difference between :format=# and :format=toString:
https://github.com/NLog/NLog/wiki/Exception-Layout-Renderer
It's happening to more people than me (see bottom comment) and happening in both Serilog and Nlog (so maby it's a EF Core thing):
https://github.com/dotnet/efcore/issues/24663#issuecomment-1349965403
Any idea how to fix without using :format=toString in nlog config?

Answer 1

NLog 4.7 allows you to override the reflection for a specific exception-type (Ex. Microsoft.EntityFrameworkCore.DbUpdateException) like this:
LogManager.Setup().SetupSerialization(s =>
s.RegisterObjectTransformation<Microsoft.EntityFrameworkCore.DbUpdateException>(ex => new {
Type = ex.GetType().ToString(),
Message = ex.Message,
StackTrace = ex.StackTrace,
Source = ex.Source,
InnerException = ex.InnerException,
})
);
See also: https://github.com/NLog/NLog/wiki/How-to-use-structured-logging#customize-object-reflection