c# - 为什么涉及 MSDTC？

Question

据我所知，MSDTC 仅在以下情况下参与：

• 您正在查询链接到另一台服务器的事务中的视图/表。

• 您在单个 TransactionScope 中使用两个 SqlConnections（或 NHibernate 使用的任何东西）

• 您正在 TransactionScope 中征用另一个事务组件（如 MSMQ 或事务文件系统）。

• 其他情况未提及。

如果我禁用 MSDTC 并运行以下代码，我会收到（服务器“服务器”上的 MSDTC 不可用）错误。

public bool Add(PurchaseOrderInfo purchaseOrderInfo)
{
    using (TransactionScope ts = new TransactionScope())
    {
        using (SqlConnection Cnn = new SqlConnection(SqlHelper.ConnStr))
        {
            Cnn.Open();

                try
                {
                    using (SqlDataReader rdr = SqlHelper.ExecuteReader(/*Tr*/Cnn, "spPurchaseOrderAdd", purchaseOrderInfo.ExpectedShipment.ShipmentID, purchaseOrderInfo.CreateDate, purchaseOrderInfo.CustomerNotes, purchaseOrderInfo.Status, purchaseOrderInfo.PurchaseOrderNumber))
                    {
                        if (rdr.Read())
                            FillPurchaseOrderInfo(rdr, ref purchaseOrderInfo, GettingDepthEnum.Level_0);
                        else
                        {
                            return false;
                        }
                    }

                    foreach (PurchaseOrderDetailInfo detailInfo in purchaseOrderInfo.Details)
                    {
                        throw new Exception("Test");
                        //if (!AddPurchaseOrderDetail(Tr, purchaseOrderInfo, detailInfo))
                        {
                            //Tr.Rollback();
                            return false;
                        }
                    }

                    return true;
                }
                catch (Exception ex)
                {
                    throw ex;
                }
                ts.Complete();
            }
        }
    }

我错过了什么吗？

更新：存储过程包含一个简单的插入语句：

INSERT INTO tblPurchaseOrder
(ShipmentID, CreateDate, CustomerNotes, PurchaseOrderState, PurchaseOrderNumber, LastActivityDate)
VALUES
(@ShipmentID, @CreateDate, @CustomerNotes, @PurchaseOrderState, @PurchaseOrderNumber, GETDATE());

--Step 2: return row that INSERTED to Client Computer.
SELECT dbo.viwGetPurchaseOrderWeight.Weight,* FROM tblPurchaseOrder LEFT OUTER JOIN viwGetPurchaseOrderWeight ON viwGetPurchaseOrderWeight.PurchaseOrderID =  tblPurchaseOrder.PurchaseOrderID WHERE (tblPurchaseOrder.PurchaseOrderID = Scope_Identity());

UPDATE2： 关闭 MSDTC 时，执行到此行时抛出异常：

using (SqlDataReader rdr = SqlHelper.ExecuteReader(/*Tr*/Cnn, "spPurchaseOrderAdd", purchaseOrderInfo.ExpectedShipment.ShipmentID, purchaseOrderInfo.CreateDate, purchaseOrderInfo.CustomerNotes, purchaseOrderInfo.Status, purchaseOrderInfo.PurchaseOrderNumber))

这意味着后续行无效。

Answer 1

只要确保不再打开连接，

using (TransactionScope transactionScope = new TransactionScope()) {
    using (SqlConnection connection = new SqlConnection(connectionString)) {
    connection.Open();
    connection.Close();
    connection.Open(); // escalates to DTC
      }
}

Answer 2

根据您的堆栈跟踪帖子，EntLib 类正在打开另一个连接。我们需要将其从交易中排除。将您的调用包装ExecuteReader在抑制事务范围内：

SqlDataReader rdr;
using (var tsSuppress = new TransactionScope(TransactionScopeOption.Suppress))
    rdr = SqlHelper.ExecuteReader(...)

这将暂时设置Transaction.Current为 null，以便新连接不会接收事务。

作为旁注，堆栈跟踪使我们能够找到问题的根本原因。

Answer 3

检查堆栈跟踪后，似乎 SQLHelper 类正在打开一个连接以从数据库中获取存储过程所需参数的列表：

   at System.Data.SqlClient.SqlConnection.OnError(SqlException exception, Boolean breakConnection)
   at System.Data.SqlClient.SqlInternalConnection.OnError(SqlException exception, Boolean breakConnection)
   at System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj)
   at System.Data.SqlClient.TdsParser.Run(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj)
   at System.Data.SqlClient.SqlDataReader.ConsumeMetaData()
   at System.Data.SqlClient.SqlDataReader.get_MetaData()
   at System.Data.SqlClient.TdsParser.TdsExecuteTransactionManagerRequest(Byte[] buffer, TransactionManagerRequestType request, String transactionName, TransactionManagerIsolationLevel isoLevel, Int32 timeout, SqlInternalTransaction transaction, TdsParserStateObject stateObj, Boolean isDelegateControlRequest)
   at System.Data.SqlClient.TdsParser.GetDTCAddress(Int32 timeout, TdsParserStateObject stateObj)
   at System.Data.SqlClient.SqlInternalConnectionTds.GetDTCAddress()
   at System.Data.SqlClient.SqlInternalConnection.EnlistNonNull(Transaction tx)
   at System.Data.SqlClient.SqlInternalConnection.Enlist(Transaction tx)
   at System.Data.SqlClient.SqlInternalConnectionTds.Activate(Transaction transaction)
   at System.Data.ProviderBase.DbConnectionInternal.ActivateConnection(Transaction transaction)
   at System.Data.ProviderBase.DbConnectionPool.GetConnection(DbConnection owningObject)
   at System.Data.ProviderBase.DbConnectionFactory.GetConnection(DbConnection owningConnection)
   at System.Data.ProviderBase.DbConnectionClosed.OpenConnection(DbConnection outerConnection, DbConnectionFactory connectionFactory)
   at System.Data.SqlClient.SqlConnection.Open()
   at Microsoft.ApplicationBlocks.Data.SqlHelperParameterCache.DiscoverSpParameterSet(SqlConnection connection, String spName, Boolean includeReturnValueParameter)
   at Microsoft.ApplicationBlocks.Data.SqlHelperParameterCache.GetSpParameterSetInternal(SqlConnection connection, String spName, Boolean includeReturnValueParameter)
   at Microsoft.ApplicationBlocks.Data.SqlHelperParameterCache.GetSpParameterSet(SqlConnection connection, String spName, Boolean includeReturnValueParameter)
   at Microsoft.ApplicationBlocks.Data.SqlHelperParameterCache.GetSpParameterSet(SqlConnection connection, String spName)
   at Microsoft.ApplicationBlocks.Data.SqlHelper.ExecuteReader(SqlConnection connection, String spName, Object[] parameterValues)
   at AlefTextileProduction.SQLServerDAL.PurchaseOrder.Add(PurchaseOrderInfo purchaseOrderInfo) 

我正在尝试解决这个问题！

Answer 4

在查看SQLHelper它的代码时，如果您使用实例的重载ExecuteReader而SqlParameter不仅仅是参数值，那么您将保存SQLHelper尝试找出哪些参数映射到什么值的步骤 - 从而节省第二次行程到数据库和第二次连接以及将您的事务提升到 MSDTC。

根据我正在查看的代码，这是您可能应该调用的方法：

Public Overloads Shared Function ExecuteReader(ByVal connectionString As String, _
                 ByVal commandType As CommandType, _
                 ByVal commandText As String, _
                 ByVal ParamArray commandParameters() As SqlParameter) As SqlDataReader

如果这不起作用，那么我建议你推出自己的 DAL。:)

希望这可以帮助。