回滚事务时出现异常-连接已关闭? [英] Exceptions when rolling back a transaction - connection already closed?
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问题描述
使用Entity Framework 6.0.0，关闭交易时看到异常.
Using Entity Framework 6.0.0, I'm seeing an exception when closing a transaction.
在对表进行并发更改时遇到了问题，因此我将其包装在事务中，现在回滚时出现异常.
We'd been having problems with concurrent changes to the table, so I wrapped it in a transaction, and now I'm getting exceptions on rollback.
代码:
public LockInfo getSharedLock(string jobid)
{
using (var myDbContext = new MyDbContext())
{
using (var transaction = myDbContext.Database.BeginTransaction())
{
try
{
this.logger.log("Attempting to get shared lock for {0}", jobid);
var mylocks =
myDbContext.joblocks.Where(j => j.customerid == this.userContext.customerid)
.Where(j => j.jobid == jobid)
.Where(j => j.operatorid == this.userContext.operatorid);
var exclusiveLock = mylocks.FirstOrDefault(
j => j.lockstatus == LockInfo.LockState.Exclusive);
if (exclusiveLock != null)
{
this.logger.log("{0} already had exclusive lock, ignoring", jobid);
return LockInfo.populate(exclusiveLock);
}
var sharedLock = mylocks.FirstOrDefault(
j => j.lockstatus == LockInfo.LockState.Shared);
if (sharedLock != null)
{
this.logger.log("{0} already had shared lock, ignoring", jobid));
sharedLock.lockdt = DateTime.Now;
myDbContext.SaveChanges();
return LockInfo.populate(sharedLock);
}
var joblock = new joblock
{
customerid = this.userContext.customerid,
operatorid = this.userContext.operatorid,
jobid = jobid,
lockstatus = LockInfo.LockState.Shared,
sharedLock.lockdt = DateTime.Now
};
myDbContext.joblocks.Add(joblock);
myDbContext.SaveChanges();
transaction.Commit();
this.logger.log("Obtained shared lock for {0}", jobid);
return LockInfo.populate(joblock);
}
catch (Exception ex)
{
transaction.Rollback();
this.logger.logException(ex, "Exception in getSharedLock(\"{0}\")", jobid);
throw;
}
}
}
}
您可以在上面的代码中看到日志记录.我们也在数据库中启用了日志记录.日志跟踪:
You can see the logging, in the code above. We have logging enabled in the database, too. The log trace:
===================
NORMAL TicketLockController.getLock("AK2015818002WL")
===================
SQL Opened connection at 9/22/2015 2:47:49 PM -05:00
===================
SQL Started transaction at 9/22/2015 2:47:49 PM -05:00
===================
NORMAL Attempting to get shared lock for AK2015818002WL
===================
SQL SELECT TOP (1) [Extent1].[customerid] AS [customerid]
,[Extent1].[jobid] AS [jobid]
,[Extent1].[lockdtdate] AS [lockdtdate]
,[Extent1].[lockdttime] AS [lockdttime]
,[Extent1].[operatorid] AS [operatorid]
,[Extent1].[lockstatus] AS [lockstatus]
,[Extent1].[changes] AS [changes]
FROM [dbo].[joblock] AS [Extent1]
WHERE ([Extent1].[customerid] = 'TESTTK')
AND ([Extent1].[jobid] = 'AK2015818002WL')
AND ([Extent1].[operatorid] = 'ADMIN')
AND (N'Exclusive' = [Extent1].[lockstatus])
===================
SQL SELECT TOP (1) [Extent1].[customerid] AS [customerid]
,[Extent1].[jobid] AS [jobid]
,[Extent1].[lockdtdate] AS [lockdtdate]
,[Extent1].[lockdttime] AS [lockdttime]
,[Extent1].[operatorid] AS [operatorid]
,[Extent1].[lockstatus] AS [lockstatus]
,[Extent1].[changes] AS [changes]
FROM [dbo].[joblock] AS [Extent1]
WHERE ([Extent1].[customerid] = 'TESTTK')
AND ([Extent1].[jobid] = 'AK2015818002WL')
AND ([Extent1].[operatorid] = 'ADMIN')
AND (N'Shared' = [Extent1].[lockstatus])
===================
SQL INSERT [dbo].[joblock] (
[customerid]
,[jobid]
,[lockdtdate]
,[lockdttime]
,[operatorid]
,[lockstatus]
,[changes]
)
VALUES (
@0
,@1
,@2
,@3
,@4
,@5
,NULL
)
===================
SQL Closed connection at 9/22/2015 2:47:50 PM -05:00
===================
EXCEPTION Unhandled exception caught: The underlying provider failed on Rollback.
===================
EXCEPTION Inner Exception: Value cannot be null.
Parameter name: connection
两个选择成功，然后由于某种原因插入失败.引发异常，并且由于某种原因，在Rollback()执行之前，连接已关闭.
The two selects are succeeding, then the insert is failing for some reason. throwing an exception, and for some reason the connection is closing before the Rollback() executes.
有什么想法我在做什么错吗?
Any ideas what I'm doing wrong?
====添加堆栈跟踪====
==== Adding stack traces ====
外部异常的Stacktrace:
Stacktrace for the outer exception:
at System.Data.Entity.Core.EntityClient.EntityTransaction.Rollback()
at korterra.kt_api.Shared.TicketLockWrangler.getSharedLock(String jobid)
at korterra.kt_ws.ApiControllers.Shared.TicketLockController.getSharedLock(TicketLockDTO ticketLockDTO)
at lambda_method(Closure , Object , Object[] )
at System.Web.Http.Controllers.ReflectedHttpActionDescriptor.ActionExecutor.<>c__DisplayClass10.<GetExecutor>b__9(Object instance, Object[] methodParameters)
at System.Web.Http.Controllers.ReflectedHttpActionDescriptor.ActionExecutor.Execute(Object instance, Object[] arguments)
at System.Web.Http.Controllers.ReflectedHttpActionDescriptor.ExecuteAsync(HttpControllerContext controllerContext, IDictionary`2 arguments, CancellationToken cancellationToken)
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at System.Web.Http.Tracing.ITraceWriterExtensions.<TraceBeginEndAsyncCore>d__18`1.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at System.Web.Http.Controllers.ApiControllerActionInvoker.<InvokeActionAsyncCore>d__0.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at System.Web.Http.Tracing.ITraceWriterExtensions.<TraceBeginEndAsyncCore>d__18`1.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at System.Web.Http.Controllers.ActionFilterResult.<ExecuteAsync>d__2.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at System.Web.Http.Filters.AuthorizationFilterAttribute.<ExecuteAuthorizationFilterAsyncCore>d__2.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at System.Web.Http.Controllers.ExceptionFilterResult.<ExecuteAsync>d__0.MoveNext()
内部异常的Stacktrace:
Stacktrace for the inner exception:
at System.Data.Entity.Utilities.Check.NotNull[T](T value, String parameterName)
at System.Data.Entity.Infrastructure.Interception.DbTransactionInterceptionContext.WithConnection(DbConnection connection)
at System.Data.Entity.Infrastructure.Interception.DbTransactionDispatcher.Rollback(DbTransaction transaction, DbInterceptionContext interceptionContext)
at System.Data.Entity.Core.EntityClient.EntityTransaction.Rollback()
推荐答案
讨论之后，我开始记录该异常，然后尝试回滚-这表明了错误.
After the discussion, I started logging the exception before trying to roll back - and that revealed the error.
交易陷入僵局:
Exception in getSharedLock("ticketnumber123456"): An error occurred while updating the entries. See the inner exception for details.
Inner Exception: An error occurred while updating the entries. See the inner exception for details.
Inner Exception: Transaction (Process ID 139) was deadlocked on lock resources with another process and has been chosen as the deadlock victim. Rerun the transaction.
根据我正在阅读的内容，当您告知某笔交易已成为僵局的受害者时，该交易已被回滚.也许这就是为什么我们要例外?
From what I'm reading, when your told a transaction has been made a deadlock victim, it's already been rolled back. Perhaps that is why we're getting an exception?
解决方法似乎是要么识别我们何时陷入僵局，而不进行回滚，要么不使用事务，并在遇到主键冲突时重试.
The fix seems to be either to recognize when we've deadlocked, and not rollback, or to not use transactions, and retry when we get a primary key violation.
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