为什么查询超时?

我有一个L2S查询,它有几个连接,在大约3秒钟内将返回11条记录。但是,它在30秒后超时,除非我指定了take参数(我使用take(20),即使它只返回11条记录),在这种情况下,它在预期的3秒时间内返回11条记录。

查询如下:

(from q in TransmittalDetails where q.TransmittalHeader.TransmittalEntityID == 196
      && q.TransmittalHeader.DateRangeBeginTimeID == 20100101
      && q.TransmittalHeader.ScenarioID == 2
      && q.LineItem.AccountType.AccountCategory.AccountGroup.
             AccountSummary.AccountSummaryID == 6
 select new {
q.LineItem.AccountType.AccountCategory.AccountGroup.AccountGroupID,
q.LineItem.AccountType.AccountCategory.AccountGroup.AccountGroup1
   }).Distinct()

这将生成如下所示的一些SQL:

DECLARE @p0 Int = 196
DECLARE @p1 Int = 20100101
DECLARE @p2 Int = 2
DECLARE @p3 Int = 6

SELECT DISTINCT [t5].[AccountGroupID], [t5].[AccountGroup] AS [AccountGroup1]
FROM [dbo].[TransmittalDetail] AS [t0]
INNER JOIN [dbo].[TransmittalHeader] AS [t1] ON [t1].[TransmittalHeaderID] = 
   [t0].[TransmittalHeaderID]
INNER JOIN [dbo].[LineItem] AS [t2] ON [t2].[LineItemID] = [t0].[LineItemID]
LEFT OUTER JOIN [dbo].[AccountType] AS [t3] ON [t3].[AccountTypeID] = 
   [t2].[AccountTypeID]
LEFT OUTER JOIN [dbo].[AccountCategory] AS [t4] ON [t4].[AccountCategoryID] = 
   [t3].[AccountCategoryID]
LEFT OUTER JOIN [dbo].[AccountGroup] AS [t5] ON [t5].[AccountGroupID] = 
   [t4].[AccountGroupID]
LEFT OUTER JOIN [dbo].[AccountSummary] AS [t6] ON [t6].[AccountSummaryID] = 
   [t5].[AccountSummaryID]
WHERE ([t1].[TransmittalEntityID] = @p0) AND ([t1].[DateRangeBeginTimeID] = @p1) 
   AND ([t1].[ScenarioID] = @p2) AND ([t6].[AccountSummaryID] = @p3)

现在,真正奇怪的是,如果我在ManagementStudio中执行该SQL,它将在3秒内返回11行,而生成它的Linq查询将在30秒的活动后超时。

指定take参数没有多大意义。我是不是碰到了虫子?

注意:无论是从应用程序还是linqpad执行take()参数,代码都会超时。同样,在app和linqpad中,它可以通过take()参数正常工作。另外,如果没有distinct,它只返回19行。