efcore: Instead of just throwing, this common error hangs and causes a memory / CPU spike.

File a bug

In Production, a very normal String or binary data would be truncated error brought down our entire server, which is an Azure Service S2 with only 1.5g memory. To my surprise, I reproduced this on my local machine, and it seems that instead of just throwing an exception, it hangs. I was able to observe the iisprocess consuming a few gigs of memory before the exception finally throws.

In Production, it eventually timed out. The resources were not released and the server remained close to 100% utilization.

I tried updating to the latest EF, although I was already on 5.0.1 - no luck.

Any idea why this is happening and how I could avoid it?

Include your code

            // other fields removed for clarity
            var user = new User()
            {
                PhoneOffice = "intentionally long field; this field is varchar(12)"
            };

            Db.User.Add(user);
            Db.SaveChanges();

Include stack traces

Include the full exception message and stack trace for any exception you encounter.

Use triple-tick fences for stack traces. For example:

String or binary data would be truncated. The statement has been terminated.
   at Microsoft.EntityFrameworkCore.Update.ReaderModificationCommandBatch.Execute(IRelationalConnection connection)
   at Microsoft.EntityFrameworkCore.Update.Internal.BatchExecutor.Execute(IEnumerable`1 commandBatches, IRelationalConnection connection)
   at Microsoft.EntityFrameworkCore.Storage.RelationalDatabase.SaveChanges(IList`1 entries)
   at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.StateManager.SaveChanges(IList`1 entriesToSave)
   at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.StateManager.SaveChanges(DbContext _, Boolean acceptAllChangesOnSuccess)
   at Microsoft.EntityFrameworkCore.SqlServer.Storage.Internal.SqlServerExecutionStrategy.Execute[TState,TResult](TState state, Func`3 operation, Func`3 verifySucceeded)
   at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.StateManager.SaveChanges(Boolean acceptAllChangesOnSuccess)
   at Microsoft.EntityFrameworkCore.DbContext.SaveChanges(Boolean acceptAllChangesOnSuccess)
   at Microsoft.EntityFrameworkCore.DbContext.SaveChanges()
   at Keystone.Web.Controllers.AdminUser.Models.UserCreator.CreateKeystoneUser(String auth0UserId) in D:\Dev\Kinetiq\Keystone\Dev\Keystone.Web\Controllers\AdminUser\Models\UserCreator.cs:line 120
   at Keystone.Web.Controllers.AdminUser.Models.UserCreator.CreateNew(UserVM model) in D:\Dev\Kinetiq\Keystone\Dev\Keystone.Web\Controllers\AdminUser\Models\UserCreator.cs:line 51
   at Keystone.Web.Controllers.AdminUser.AdminUserController.Create(UserVM model) in D:\Dev\Kinetiq\Keystone\Dev\Keystone.Web\Controllers\AdminUser\AdminUserController.cs:line 95
   at Microsoft.AspNetCore.Mvc.Infrastructure.ActionMethodExecutor.SyncActionResultExecutor.Execute(IActionResultTypeMapper mapper, ObjectMethodExecutor executor, Object controller, Object[] arguments)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.<<InvokeActionMethodAsync>g__Logged|12_1>d.MoveNext()

Include provider and version information

EF Core version: 5.0.1 and 5.0.2 Database provider: Microsoft.EntityFrameworkCore.SqlServer Target framework: net5.0 Operating system: Windows 10, and Azure Service IDE: Visual Studio 2019 16.8.4