ASP.NET Core 6+EF Core 6随机抛出事务关联异常求助

约45天前，我将一个基于.NET 5的项目升级到了.NET 6，该项目包含8个网站，均使用ASP.NET Core 6和Entity Framework Core 6，所有网站通过共享配置流程从AWS Parameter Store获取配置。

升级后，随机出现如下异常：

The specified transaction is not associated with the current connection. Only transactions associated with the current connection may be used.

立即重试请求通常能解决问题，但并非每次都有效。我记得在.NET 5、ASP.NET Core 5和Entity Framework Core 5环境下从未出现此类问题，不确定如何解决。以下是我的EF配置代码，是否有人能发现可能的原因？5到6版本间代码并未大幅改动……

public static IServiceCollection AddApplicationDbContextPool(
    this IServiceCollection services,
    IConfig config,
    int poolSize = 1024) {
    if (config is null) {
        throw new ArgumentNullException(nameof(config));
    }

    services.AddDbContextPool<ApplicationContext>(
        _ => {
            _.UseSqlServer(config.DefaultConnection,
                           __ => {
                               __.UseNetTopologySuite();

                               if (!config.IsDevelopment) {
                                   return;
                               }

                               __.CommandTimeout(int.MaxValue);
                           });

            if (!config.IsDevelopment) {
                return;
            }

            _.EnableDetailedErrors()
             .EnableSensitiveDataLogging();
        }, poolSize);

    services.AddDbContextPool<SerilogContext>(
        _ => {
            _.UseSqlServer(config.SerilogConnection,
                           __ => {
                               __.UseNetTopologySuite();// may be unnecessary, but keeping until I verify.

                               if (!config.IsDevelopment) {
                                   return;
                               }

                               __.CommandTimeout(int.MaxValue);
                           });

            if (!config.IsDevelopment) {
                return;
            }

            _.EnableDetailedErrors()
             .EnableSensitiveDataLogging();
        });

    NtsGeometryServices.Instance = new NtsGeometryServices(
        NetTopologySuite.Geometries.Implementation.CoordinateArraySequenceFactory.Instance,
        new PrecisionModel(1000d),
        4326,
        GeometryOverlay.NG,
        new CoordinateEqualityComparer()
    );

    return services;
}

后端数据库为SQL Server 2019。升级时更换了数据库服务器，新实例配置更优、硬件性能更强，但我怀疑问题出在应用与数据库的交互而非数据库本身。

其中一个高负载应用使用Dapper操作数据库，以下是Dapper配置，该应用使用Singleton作用域（Transient可移除，已无依赖）：

public static IServiceCollection AddApplicationDapper(
    this IServiceCollection services,
    IConfig config,
    ServiceLifetime serviceLifetime = ServiceLifetime.Transient) {
    if (config is null) {
        throw new ArgumentNullException(nameof(config));
    }

    SqlMapper.AddTypeHandler(new GeometryHandler<Point>(true));
    SqlMapper.AddTypeHandler(new GeometryHandler<Polygon>(true));

    return serviceLifetime == ServiceLifetime.Singleton
        ? services.AddSingleton(
            _ => new SqlConnection(config.DefaultConnection))
        : services.AddTransient(
            _ => new SqlConnection(config.DefaultConnection));
}

是否可能是应用中广泛使用async/await导致的？我几乎在所有地方都使用了.ConfigureAwait(false)，线程切换会不会是原因？这部分在5到6版本间也未大幅改动。

我曾怀疑是EF Core Triggered包导致，已移除该包，但异常仍持续出现，恳请各位提供帮助！

@Dai

关于单例SqlConnection的Dapper使用说明：仅在一个应用中使用，该应用是与其他ASP.NET Core应用统一管理的ASP.NET Core程序，但不处理Web请求，而是作为IoT监听器和处理器，注册了几个单例IHostedServices类。IoT服务监听特定设备的报告，然后传递给处理服务，仅处理服务使用SqlConnection实例，属于一对一使用，因此单例SqlConnection可正常工作，此配置从.NET Core 2.0起一直沿用。

出现异常的并非该项目，而是其他使用EF Core操作数据库的项目。我认为IoT应用中单个处理服务使用的单例SqlConnection并非问题原因。

@Gert Arnold

我99.9991%确定所有异步操作都已使用await，至少ReSharper会在遗漏时提示。

System.InvalidOperationException: The specified transaction is not associated with the current connection. Only transactions associated with the current connection may be used.
    at Microsoft.EntityFrameworkCore.Storage.RelationalTransaction..ctor(IRelationalConnection connection, DbTransaction transaction, Guid transactionId, IDiagnosticsLogger`1 logger, Boolean transactionOwned, ISqlGenerationHelper sqlGenerationHelper)
    at Microsoft.EntityFrameworkCore.SqlServer.Storage.Internal.SqlServerTransactionFactory.Create(IRelationalConnection connection, DbTransaction transaction, Guid transactionId, IDiagnosticsLogger`1 logger, Boolean transactionOwned)
    at Microsoft.EntityFrameworkCore.Storage.RelationalConnection.BeginTransactionAsync(IsolationLevel isolationLevel, CancellationToken cancellationToken)
    at Microsoft.EntityFrameworkCore.Storage.RelationalConnection.BeginTransactionAsync(CancellationToken cancellationToken)
    at Microsoft.EntityFrameworkCore.Update.Internal.BatchExecutor.ExecuteAsync(IEnumerable`1 commandBatches, IRelationalConnection connection, CancellationToken cancellationToken)
    at Microsoft.EntityFrameworkCore.Update.Internal.BatchExecutor.ExecuteAsync(IEnumerable`1 commandBatches, IRelationalConnection connection, CancellationToken cancellationToken)
    at Microsoft.EntityFrameworkCore.Update.Internal.BatchExecutor.ExecuteAsync(IEnumerable`1 commandBatches, IRelationalConnection connection, CancellationToken cancellationToken)
    at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.StateManager.SaveChangesAsync(IList`1 entriesToSave, CancellationToken cancellationToken)
    at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.StateManager.SaveChangesAsync(StateManager stateManager, Boolean acceptAllChangesOnSuccess, CancellationToken cancellationToken)
    at Microsoft.EntityFrameworkCore.SqlServer.Storage.Internal.SqlServerExecutionStrategy.ExecuteAsync[TState,TResult](TState state, Func`4 operation, Func`4 verifySucceeded, CancellationToken cancellationToken)
    at Microsoft.EntityFrameworkCore.DbContext.SaveChangesAsync(Boolean acceptAllChangesOnSuccess, CancellationToken cancellationToken)
    at Microsoft.EntityFrameworkCore.DbContext.SaveChangesAsync(Boolean acceptAllChangesOnSuccess, CancellationToken cancellationToken)
    at REDACTED.App.Devices.Locate.CommandHandler.Handle(Command command, CancellationToken cancellationToken) in E:\Software Development\REDACTED\REDACTED.App\Features\Devices\Locate.cs:line 69

内容的提问来源于stack exchange，提问作者Gup3rSuR4c