错误 NHibernate.Util.ADOExceptionReporter 请求的操作无法完成，因为连接已断开
ERROR NHibernate.Util.ADOExceptionReporter The requested operation cannot be completed because the connection has been broken
我有一个 ASP.NET MVC 应用程序，以 nHibernate 作为 ORM（使用 SQL 服务器作为数据库）。
每 5-6 个请求，就会抛出一个异常，其中包含上述标题中描述的随机错误。
这仅发生在 GET 个请求上并且以：
开头
ERROR While preparing SELECT ..
自从我将 NHibernate 4.x 升级到 NHibernate 5.0.3（现在是 5.1.1）后，这些问题就开始了。在此过程中我还更新了目标框架，以前是.NET 4.5.2 现在是.NET 4.7.2。
我几乎检查了所有内容，确保没有任何连接泄漏或针对数据库的超时，但错误仍然存在。已尝试从连接字符串中关闭“TransparentNetworkIPResolution”和“Enlist”功能 - 问题仍然存在。
任何关于解决问题的想法都将非常受欢迎。
这是以下异常的罪魁祸首 (DepartmentService:838):
var department = _departmentRepository.Get(departmentId);
场景如下，我有多个网格，因此多个请求被触发到同一个动作。同一个页面每刷新 5-6 次，其中一个请求就会失败（失败的请求是随机的，即有时是第一个，有时是第二个，依此类推）。
这是我日志中的完整异常片段：
2020-06-26 13:25:16,297 [50] ERROR NHibernate.Util.ADOExceptionReporter [(null)] - While preparing SELECT department0_.DepartmentId as departmentid1_22_0_, department0_.CreatedAt as createdat4_22_0_, department0_.ModifiedAt as modifiedat5_22_0_, department0_.Name as name2_22_0_, department0_.Status as status6_22_0_, department0_.CreatedBy as createdby7_22_0_, department0_.ModifiedBy as modifiedby8_22_0_, department0_.SiteId as siteid3_22_0_ FROM dbo.Departments department0_ WHERE department0_.DepartmentId=@p0 an error occurred
2020-06-26 13:25:16,298 [50] ERROR NHibernate.Util.ADOExceptionReporter [(null)] - The requested operation cannot be completed because the connection has been broken.
2020-06-26 13:25:16,300 [50] ERROR [(null)] - NHibernate.ADOException: While preparing SELECT department0_.DepartmentId as departmentid1_22_0_, department0_.CreatedAt as createdat4_22_0_, department0_.ModifiedAt as modifiedat5_22_0_, department0_.Name as name2_22_0_, department0_.Status as status6_22_0_, department0_.CreatedBy as createdby7_22_0_, department0_.ModifiedBy as modifiedby8_22_0_, department0_.SiteId as siteid3_22_0_ FROM dbo.Departments department0_ WHERE department0_.DepartmentId=@p0 an error occurred ---> System.InvalidOperationException: The requested operation cannot be completed because the connection has been broken.
at System.Data.SqlClient.SqlInternalConnectionTds.ExecuteTransaction(TransactionRequest transactionRequest, String name, IsolationLevel iso, SqlInternalTransaction internalTransaction, Boolean isDelegateControlRequest)
at System.Data.SqlClient.SqlDelegatedTransaction.Initialize()
at System.Transactions.TransactionStatePSPEOperation.PSPEInitialize(InternalTransaction tx, IPromotableSinglePhaseNotification promotableSinglePhaseNotification, Guid promoterType)
at System.Transactions.TransactionStateActive.EnlistPromotableSinglePhase(InternalTransaction tx, IPromotableSinglePhaseNotification promotableSinglePhaseNotification, Transaction atomicTransaction, Guid promoterType)
at System.Transactions.Transaction.EnlistPromotableSinglePhase(IPromotableSinglePhaseNotification promotableSinglePhaseNotification, Guid promoterType)
at System.Transactions.Transaction.EnlistPromotableSinglePhase(IPromotableSinglePhaseNotification promotableSinglePhaseNotification)
at System.Data.SqlClient.SqlInternalConnection.EnlistNonNull(Transaction tx)
at System.Data.SqlClient.SqlInternalConnection.Enlist(Transaction tx)
at System.Data.ProviderBase.DbConnectionInternal.ActivateConnection(Transaction transaction)
at System.Data.ProviderBase.DbConnectionPool.PrepareConnection(DbConnection owningObject, DbConnectionInternal obj, Transaction transaction)
at System.Data.ProviderBase.DbConnectionPool.TryGetConnection(DbConnection owningObject, UInt32 waitForMultipleObjectsTimeout, Boolean allowCreate, Boolean onlyOneCheckConnection, DbConnectionOptions userOptions, DbConnectionInternal& connection)
at System.Data.ProviderBase.DbConnectionPool.TryGetConnection(DbConnection owningObject, TaskCompletionSource1 retry, DbConnectionOptions userOptions, DbConnectionInternal& connection) at System.Data.ProviderBase.DbConnectionFactory.TryGetConnection(DbConnection owningConnection, TaskCompletionSource1 retry, DbConnectionOptions userOptions, DbConnectionInternal oldConnection, DbConnectionInternal& connection)
at System.Data.ProviderBase.DbConnectionInternal.TryOpenConnectionInternal(DbConnection outerConnection, DbConnectionFactory connectionFactory, TaskCompletionSource1 retry, DbConnectionOptions userOptions) at System.Data.SqlClient.SqlConnection.TryOpenInner(TaskCompletionSource1 retry)
at System.Data.SqlClient.SqlConnection.TryOpen(TaskCompletionSource`1 retry)
at System.Data.SqlClient.SqlConnection.Open()
at NHibernate.Connection.DriverConnectionProvider.GetConnection()
at NHibernate.AdoNet.ConnectionManager.GetConnection()
at NHibernate.AdoNet.AbstractBatcher.Prepare(DbCommand cmd)
--- End of inner exception stack trace ---
at NHibernate.AdoNet.AbstractBatcher.Prepare(DbCommand cmd)
at NHibernate.AdoNet.AbstractBatcher.ExecuteReader(DbCommand cmd)
at NHibernate.Loader.Loader.GetResultSet(DbCommand st, QueryParameters queryParameters, ISessionImplementor session, IResultTransformer forcedResultTransformer)
at NHibernate.Loader.Loader.DoQuery(ISessionImplementor session, QueryParameters queryParameters, Boolean returnProxies, IResultTransformer forcedResultTransformer)
at NHibernate.Loader.Loader.DoQueryAndInitializeNonLazyCollections(ISessionImplementor session, QueryParameters queryParameters, Boolean returnProxies, IResultTransformer forcedResultTransformer)
at NHibernate.Loader.Loader.LoadEntity(ISessionImplementor session, Object id, IType identifierType, Object optionalObject, String optionalEntityName, Object optionalIdentifier, IEntityPersister persister)
at NHibernate.Loader.Entity.AbstractEntityLoader.Load(ISessionImplementor session, Object id, Object optionalObject, Object optionalId)
at NHibernate.Loader.Entity.AbstractEntityLoader.Load(Object id, Object optionalObject, ISessionImplementor session)
at NHibernate.Persister.Entity.AbstractEntityPersister.Load(Object id, Object optionalObject, LockMode lockMode, ISessionImplementor session)
at NHibernate.Event.Default.DefaultLoadEventListener.LoadFromDatasource(LoadEvent event, IEntityPersister persister, EntityKey keyToLoad, LoadType options)
at NHibernate.Event.Default.DefaultLoadEventListener.DoLoad(LoadEvent event, IEntityPersister persister, EntityKey keyToLoad, LoadType options)
at NHibernate.Event.Default.DefaultLoadEventListener.Load(LoadEvent event, IEntityPersister persister, EntityKey keyToLoad, LoadType options)
at NHibernate.Event.Default.DefaultLoadEventListener.ProxyOrLoad(LoadEvent event, IEntityPersister persister, EntityKey keyToLoad, LoadType options)
at NHibernate.Event.Default.DefaultLoadEventListener.OnLoad(LoadEvent event, LoadType loadType)
at NHibernate.Impl.SessionImpl.FireLoad(LoadEvent event, LoadType loadType)
at NHibernate.Impl.SessionImpl.Get(String entityName, Object id)
at NHibernate.Impl.SessionImpl.Get[T](Object id)
at Codera.Data.NHibernate.NHRepository1.Get(Object id) at Castle.Proxies.Invocations.NHRepository1_Get_10.InvokeMethodOnTarget()
at Castle.DynamicProxy.AbstractInvocation.Proceed()
at ISOQuest.Data.NHibernate.Interceptors.MethodInterceptor.Intercept(IInvocation invocation) in C:\Projects\ISOQuestGen6\ISOQuest.Data.NHibernate\Interceptors\MethodInterceptor.cs:line 49
at Castle.DynamicProxy.AbstractInvocation.Proceed()
at Castle.Proxies.DepartmentRepositoryProxy.Get(Object id)
at ISOQuest.Business.Services.DepartmentService.GetDepartmentAdministrators(Guid departmentId, Int32 type) in C:\Projects\ISOQuestGen6\Modules\ISOQuest\ISOQuest.Business\Services\Department\DepartmentService.cs:line 838
at ISOQuest.Web.Controllers.Api.DepartmentsController.LoadDepartmentAdministrators(Guid departmentId, Int32 type) in C:\Projects\ISOQuestGen6\Modules\ISOQuest\ISOQuest.Web\Controllers\Api\DepartmentsController.cs:line 454
at lambda_method(Closure , ControllerBase , Object[] )
at System.Web.Mvc.ReflectedActionDescriptor.Execute(ControllerContext controllerContext, IDictionary2 parameters) at System.Web.Mvc.ControllerActionInvoker.InvokeActionMethod(ControllerContext controllerContext, ActionDescriptor actionDescriptor, IDictionary2 parameters)
at System.Web.Mvc.Async.AsyncControllerActionInvoker.b__39(IAsyncResult asyncResult, ActionInvocation innerInvokeState)
at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResult2.CallEndDelegate(IAsyncResult asyncResult) at System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeActionMethod(IAsyncResult asyncResult) at System.Web.Mvc.Async.AsyncControllerActionInvoker.AsyncInvocationWithFilters.<InvokeActionMethodFilterAsynchronouslyRecursive>b__3d() at System.Web.Mvc.Async.AsyncControllerActionInvoker.AsyncInvocationWithFilters.<>c__DisplayClass46.<InvokeActionMethodFilterAsynchronouslyRecursive>b__3f() at System.Web.Mvc.Async.AsyncControllerActionInvoker.AsyncInvocationWithFilters.<>c__DisplayClass46.<InvokeActionMethodFilterAsynchronouslyRecursive>b__3f() at System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeActionMethodWithFilters(IAsyncResult asyncResult) at System.Web.Mvc.Async.AsyncControllerActionInvoker.<>c__DisplayClass21.<>c__DisplayClass2b.<BeginInvokeAction>b__1c() at System.Web.Mvc.Async.AsyncControllerActionInvoker.<>c__DisplayClass21.<BeginInvokeAction>b__1e(IAsyncResult asyncResult) at System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeAction(IAsyncResult asyncResult) at System.Web.Mvc.Controller.<BeginExecuteCore>b__1d(IAsyncResult asyncResult, ExecuteCoreState innerState) at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncVoid1.CallEndDelegate(IAsyncResult asyncResult)
at System.Web.Mvc.Controller.EndExecuteCore(IAsyncResult asyncResult)
at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncVoid1.CallEndDelegate(IAsyncResult asyncResult) at System.Web.Mvc.Controller.EndExecute(IAsyncResult asyncResult) at System.Web.Mvc.MvcHandler.<BeginProcessRequest>b__5(IAsyncResult asyncResult, ProcessRequestState innerState) at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncVoid1.CallEndDelegate(IAsyncResult asyncResult)
at System.Web.Mvc.MvcHandler.EndProcessRequest(IAsyncResult asyncResult)
at System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()
at System.Web.HttpApplication.ExecuteStepImpl(IExecutionStep step)
at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)
尝试了所有方法后，我转回了 nHibernate 5.X 更改日志，最后在这里：https://nhibernate.info/doc/nhibernate-reference/transactions.html，并在更改日志的最后发现了这个小注释：
As of NHibernate v5.0, FlushMode.Commit requires the configuration setting transaction.use_connection_on_system_prepare to be true for flushing from transaction scope commit. Otherwise, it will be your responsibility to flush the session before completing the scope.
Using transaction.use_connection_on_system_prepare can cause undesired transaction promotions to distributed: it requires using a dedicated connection for flushing, and it delays session disposal (if done inside the scope) to the scope disposal. If you want to avoid this, set this setting to false and manually flush your sessions.
For new applications, it is recommended to set transaction.use_connection_on_system_prepare to false, and to flush explicitly your sessions before scope completion. For old applications, consider checking how sessions are flushed, and if possible switch it to false too.
基本上，我们在迁移到 nHibernate 5 时更改的一个设置是 FlushMode 从“Auto”到“Commit”，但不知何故错过了这个标志（transaction.use_connection_on_system_prepare = false).
希望这会帮助其他使用旧系统尝试升级的人！
我有一个 ASP.NET MVC 应用程序，以 nHibernate 作为 ORM（使用 SQL 服务器作为数据库）。
每 5-6 个请求，就会抛出一个异常，其中包含上述标题中描述的随机错误。
这仅发生在 GET 个请求上并且以：
ERROR While preparing SELECT ..
自从我将 NHibernate 4.x 升级到 NHibernate 5.0.3（现在是 5.1.1）后，这些问题就开始了。在此过程中我还更新了目标框架，以前是.NET 4.5.2 现在是.NET 4.7.2。
我几乎检查了所有内容，确保没有任何连接泄漏或针对数据库的超时，但错误仍然存在。已尝试从连接字符串中关闭“TransparentNetworkIPResolution”和“Enlist”功能 - 问题仍然存在。
任何关于解决问题的想法都将非常受欢迎。
这是以下异常的罪魁祸首 (DepartmentService:838):
var department = _departmentRepository.Get(departmentId);
场景如下，我有多个网格，因此多个请求被触发到同一个动作。同一个页面每刷新 5-6 次，其中一个请求就会失败（失败的请求是随机的，即有时是第一个，有时是第二个，依此类推）。
这是我日志中的完整异常片段：
2020-06-26 13:25:16,297 [50] ERROR NHibernate.Util.ADOExceptionReporter [(null)] - While preparing SELECT department0_.DepartmentId as departmentid1_22_0_, department0_.CreatedAt as createdat4_22_0_, department0_.ModifiedAt as modifiedat5_22_0_, department0_.Name as name2_22_0_, department0_.Status as status6_22_0_, department0_.CreatedBy as createdby7_22_0_, department0_.ModifiedBy as modifiedby8_22_0_, department0_.SiteId as siteid3_22_0_ FROM dbo.Departments department0_ WHERE department0_.DepartmentId=@p0 an error occurred 2020-06-26 13:25:16,298 [50] ERROR NHibernate.Util.ADOExceptionReporter [(null)] - The requested operation cannot be completed because the connection has been broken.
2020-06-26 13:25:16,300 [50] ERROR [(null)] - NHibernate.ADOException: While preparing SELECT department0_.DepartmentId as departmentid1_22_0_, department0_.CreatedAt as createdat4_22_0_, department0_.ModifiedAt as modifiedat5_22_0_, department0_.Name as name2_22_0_, department0_.Status as status6_22_0_, department0_.CreatedBy as createdby7_22_0_, department0_.ModifiedBy as modifiedby8_22_0_, department0_.SiteId as siteid3_22_0_ FROM dbo.Departments department0_ WHERE department0_.DepartmentId=@p0 an error occurred ---> System.InvalidOperationException: The requested operation cannot be completed because the connection has been broken.
at System.Data.SqlClient.SqlInternalConnectionTds.ExecuteTransaction(TransactionRequest transactionRequest, String name, IsolationLevel iso, SqlInternalTransaction internalTransaction, Boolean isDelegateControlRequest)
at System.Data.SqlClient.SqlDelegatedTransaction.Initialize()
at System.Transactions.TransactionStatePSPEOperation.PSPEInitialize(InternalTransaction tx, IPromotableSinglePhaseNotification promotableSinglePhaseNotification, Guid promoterType)
at System.Transactions.TransactionStateActive.EnlistPromotableSinglePhase(InternalTransaction tx, IPromotableSinglePhaseNotification promotableSinglePhaseNotification, Transaction atomicTransaction, Guid promoterType)
at System.Transactions.Transaction.EnlistPromotableSinglePhase(IPromotableSinglePhaseNotification promotableSinglePhaseNotification, Guid promoterType)
at System.Transactions.Transaction.EnlistPromotableSinglePhase(IPromotableSinglePhaseNotification promotableSinglePhaseNotification)
at System.Data.SqlClient.SqlInternalConnection.EnlistNonNull(Transaction tx)
at System.Data.SqlClient.SqlInternalConnection.Enlist(Transaction tx)
at System.Data.ProviderBase.DbConnectionInternal.ActivateConnection(Transaction transaction)
at System.Data.ProviderBase.DbConnectionPool.PrepareConnection(DbConnection owningObject, DbConnectionInternal obj, Transaction transaction)
at System.Data.ProviderBase.DbConnectionPool.TryGetConnection(DbConnection owningObject, UInt32 waitForMultipleObjectsTimeout, Boolean allowCreate, Boolean onlyOneCheckConnection, DbConnectionOptions userOptions, DbConnectionInternal& connection)
at System.Data.ProviderBase.DbConnectionPool.TryGetConnection(DbConnection owningObject, TaskCompletionSource1 retry, DbConnectionOptions userOptions, DbConnectionInternal& connection) at System.Data.ProviderBase.DbConnectionFactory.TryGetConnection(DbConnection owningConnection, TaskCompletionSource1 retry, DbConnectionOptions userOptions, DbConnectionInternal oldConnection, DbConnectionInternal& connection)
at System.Data.ProviderBase.DbConnectionInternal.TryOpenConnectionInternal(DbConnection outerConnection, DbConnectionFactory connectionFactory, TaskCompletionSource1 retry, DbConnectionOptions userOptions) at System.Data.SqlClient.SqlConnection.TryOpenInner(TaskCompletionSource1 retry)
at System.Data.SqlClient.SqlConnection.TryOpen(TaskCompletionSource`1 retry)
at System.Data.SqlClient.SqlConnection.Open()
at NHibernate.Connection.DriverConnectionProvider.GetConnection()
at NHibernate.AdoNet.ConnectionManager.GetConnection()
at NHibernate.AdoNet.AbstractBatcher.Prepare(DbCommand cmd)
--- End of inner exception stack trace ---at NHibernate.AdoNet.AbstractBatcher.Prepare(DbCommand cmd)
at NHibernate.AdoNet.AbstractBatcher.ExecuteReader(DbCommand cmd)
at NHibernate.Loader.Loader.GetResultSet(DbCommand st, QueryParameters queryParameters, ISessionImplementor session, IResultTransformer forcedResultTransformer)
at NHibernate.Loader.Loader.DoQuery(ISessionImplementor session, QueryParameters queryParameters, Boolean returnProxies, IResultTransformer forcedResultTransformer)
at NHibernate.Loader.Loader.DoQueryAndInitializeNonLazyCollections(ISessionImplementor session, QueryParameters queryParameters, Boolean returnProxies, IResultTransformer forcedResultTransformer) at NHibernate.Loader.Loader.LoadEntity(ISessionImplementor session, Object id, IType identifierType, Object optionalObject, String optionalEntityName, Object optionalIdentifier, IEntityPersister persister) at NHibernate.Loader.Entity.AbstractEntityLoader.Load(ISessionImplementor session, Object id, Object optionalObject, Object optionalId) at NHibernate.Loader.Entity.AbstractEntityLoader.Load(Object id, Object optionalObject, ISessionImplementor session) at NHibernate.Persister.Entity.AbstractEntityPersister.Load(Object id, Object optionalObject, LockMode lockMode, ISessionImplementor session) at NHibernate.Event.Default.DefaultLoadEventListener.LoadFromDatasource(LoadEvent event, IEntityPersister persister, EntityKey keyToLoad, LoadType options) at NHibernate.Event.Default.DefaultLoadEventListener.DoLoad(LoadEvent event, IEntityPersister persister, EntityKey keyToLoad, LoadType options) at NHibernate.Event.Default.DefaultLoadEventListener.Load(LoadEvent event, IEntityPersister persister, EntityKey keyToLoad, LoadType options) at NHibernate.Event.Default.DefaultLoadEventListener.ProxyOrLoad(LoadEvent event, IEntityPersister persister, EntityKey keyToLoad, LoadType options) at NHibernate.Event.Default.DefaultLoadEventListener.OnLoad(LoadEvent event, LoadType loadType) at NHibernate.Impl.SessionImpl.FireLoad(LoadEvent event, LoadType loadType) at NHibernate.Impl.SessionImpl.Get(String entityName, Object id) at NHibernate.Impl.SessionImpl.Get[T](Object id) at Codera.Data.NHibernate.NHRepository1.Get(Object id) at Castle.Proxies.Invocations.NHRepository1_Get_10.InvokeMethodOnTarget() at Castle.DynamicProxy.AbstractInvocation.Proceed() at ISOQuest.Data.NHibernate.Interceptors.MethodInterceptor.Intercept(IInvocation invocation) in C:\Projects\ISOQuestGen6\ISOQuest.Data.NHibernate\Interceptors\MethodInterceptor.cs:line 49 at Castle.DynamicProxy.AbstractInvocation.Proceed() at Castle.Proxies.DepartmentRepositoryProxy.Get(Object id) at ISOQuest.Business.Services.DepartmentService.GetDepartmentAdministrators(Guid departmentId, Int32 type) in C:\Projects\ISOQuestGen6\Modules\ISOQuest\ISOQuest.Business\Services\Department\DepartmentService.cs:line 838 at ISOQuest.Web.Controllers.Api.DepartmentsController.LoadDepartmentAdministrators(Guid departmentId, Int32 type) in C:\Projects\ISOQuestGen6\Modules\ISOQuest\ISOQuest.Web\Controllers\Api\DepartmentsController.cs:line 454 at lambda_method(Closure , ControllerBase , Object[] ) at System.Web.Mvc.ReflectedActionDescriptor.Execute(ControllerContext controllerContext, IDictionary2 parameters) at System.Web.Mvc.ControllerActionInvoker.InvokeActionMethod(ControllerContext controllerContext, ActionDescriptor actionDescriptor, IDictionary2 parameters) at System.Web.Mvc.Async.AsyncControllerActionInvoker.b__39(IAsyncResult asyncResult, ActionInvocation innerInvokeState) at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResult2.CallEndDelegate(IAsyncResult asyncResult) at System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeActionMethod(IAsyncResult asyncResult) at System.Web.Mvc.Async.AsyncControllerActionInvoker.AsyncInvocationWithFilters.<InvokeActionMethodFilterAsynchronouslyRecursive>b__3d() at System.Web.Mvc.Async.AsyncControllerActionInvoker.AsyncInvocationWithFilters.<>c__DisplayClass46.<InvokeActionMethodFilterAsynchronouslyRecursive>b__3f() at System.Web.Mvc.Async.AsyncControllerActionInvoker.AsyncInvocationWithFilters.<>c__DisplayClass46.<InvokeActionMethodFilterAsynchronouslyRecursive>b__3f() at System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeActionMethodWithFilters(IAsyncResult asyncResult) at System.Web.Mvc.Async.AsyncControllerActionInvoker.<>c__DisplayClass21.<>c__DisplayClass2b.<BeginInvokeAction>b__1c() at System.Web.Mvc.Async.AsyncControllerActionInvoker.<>c__DisplayClass21.<BeginInvokeAction>b__1e(IAsyncResult asyncResult) at System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeAction(IAsyncResult asyncResult) at System.Web.Mvc.Controller.<BeginExecuteCore>b__1d(IAsyncResult asyncResult, ExecuteCoreState innerState) at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncVoid1.CallEndDelegate(IAsyncResult asyncResult) at System.Web.Mvc.Controller.EndExecuteCore(IAsyncResult asyncResult) at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncVoid1.CallEndDelegate(IAsyncResult asyncResult) at System.Web.Mvc.Controller.EndExecute(IAsyncResult asyncResult) at System.Web.Mvc.MvcHandler.<BeginProcessRequest>b__5(IAsyncResult asyncResult, ProcessRequestState innerState) at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncVoid1.CallEndDelegate(IAsyncResult asyncResult) at System.Web.Mvc.MvcHandler.EndProcessRequest(IAsyncResult asyncResult) at System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() at System.Web.HttpApplication.ExecuteStepImpl(IExecutionStep step) at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)
尝试了所有方法后，我转回了 nHibernate 5.X 更改日志，最后在这里：https://nhibernate.info/doc/nhibernate-reference/transactions.html，并在更改日志的最后发现了这个小注释：
As of NHibernate v5.0, FlushMode.Commit requires the configuration setting transaction.use_connection_on_system_prepare to be true for flushing from transaction scope commit. Otherwise, it will be your responsibility to flush the session before completing the scope.Using transaction.use_connection_on_system_prepare can cause undesired transaction promotions to distributed: it requires using a dedicated connection for flushing, and it delays session disposal (if done inside the scope) to the scope disposal. If you want to avoid this, set this setting to false and manually flush your sessions.
For new applications, it is recommended to set transaction.use_connection_on_system_prepare to false, and to flush explicitly your sessions before scope completion. For old applications, consider checking how sessions are flushed, and if possible switch it to false too.
基本上，我们在迁移到 nHibernate 5 时更改的一个设置是 FlushMode 从“Auto”到“Commit”，但不知何故错过了这个标志（transaction.use_connection_on_system_prepare = false).
希望这会帮助其他使用旧系统尝试升级的人！