EF编译查询偶尔会导致SqlException

Question

我正在使用一个编译查询，它在应用程序中执行一部分查询逻辑非常复杂，它将编译查询抽象为 Func 后面。我会定期（大约一千次）收到以下异常：

SqlException:
The parameterized query '(@p__linq__0 int,@p__linq__1 nvarchar(4000),@p__linq__2 varchar(' expects the parameter '@p__linq__1', which was not supplied.

And InvalidOperationException:
Parameters cannot be added or removed from the parameter collection, and the parameter collection cannot be cleared after a query has been evaluated or its trace string has been retrieved.  

看到第二个异常后，我的第一反应是遇到了并发问题。这是通过 WCF 服务在服务行为的默认配置下使用 basicHttpBinding 完成的，这意味着并发模式是单一的。我没有使用 InstanceContextMode 单一，而是使用默认的 PerSession，这可能会导致问题吗？

所涉及的数据库被大量使用，所以我也怀疑我可能在查询期间超时，但我无法与我看到的异常建立逻辑关联。

更糟糕的是，我无法在本地机器上重现这些错误，异常发生在晚上远程服务器上的处理例程中，而且每晚只有一两次。希望其他人也经历过类似的事情。我可以尝试一些事情，例如更改 instancecontextmode、增加 SQL Server 超时，但我更愿意在尝试解决方法之前知道问题出在哪里。我确实记录了一些异常实例，这是 InvalidOperationExceptions 之一的堆栈帧：

System.Data.Objects.ObjectParameterCollection.Add(ObjectParameter parameter)
System.Data.Objects.ELinq.CompiledELinqQueryState.GetExecutionPlan(Nullable`1 forMergeOption)
System.Data.Objects.ObjectQuery`1.GetResults(Nullable`1 forMergeOption)
System.Data.Objects.ObjectQuery`1.System.Collections.Generic.IEnumerable<T>.GetEnumerator()
System.Linq.Enumerable.Count[TSource](IEnumerable`1 source, Func`2 predicate)
Processor.Processor.<>c__DisplayClass10.<GetObjectContexts>b__9(ObjectContextMetadata q) in C:\Documents and Settings\eugarps\My Documents\SomeService-development\Processor\Processor.cs:line 174
System.Linq.Enumerable.WhereSelectEnumerableIterator`2.MoveNext()
System.Linq.Enumerable.<DistinctIterator>d__81`1.MoveNext()
System.Linq.Enumerable.Contains[TSource](IEnumerable`1 source, TSource value, IEqualityComparer`1 comparer)
Processor.Processor.<>c__DisplayClass10.<GetObjectContexts>b__c(ObjectContextMetadata q) in C:\Documents and Settings\eugarps\My Documents\SomeService-development\Processor\Processor.cs:line 179
System.Linq.Enumerable.WhereEnumerableIterator`1.MoveNext()
Processor.Processor.ResolveGeoCode(AddressItem address, String product) in C:\Documents and Settings\eugarps\My Documents\SomeService-development\Processor\Processor.cs:line 273
Company.ProcessingLogic.SomeService.SomeServiceService.ResolveDepotWithMask(AddressItem address, String product, DeliveryMap map, IGeocoder geocoder) in C:\Documents and Settings\eugarps\My Documents\SomeService-development\SomeServiceService\SomeServiceService.cs:line 136
Company.ProcessingLogic.SomeService.SomeServiceService.ResolveDepotWithMask(AddressItem address, String product, DeliveryMap map) in C:\Documents and Settings\eugarps\My Documents\SomeService-development\SomeServiceService\SomeServiceService.cs:line 59
Company.ProcessingLogic.SomeService.SomeServiceService.ResolveDepot(AddressItem address, String product) in C:\Documents and Settings\eugarps\My Documents\SomeService-development\SomeServiceService\SomeServiceService.cs:line 53
SyncInvokeResolveDepot(Object , Object[] , Object[] )
System.ServiceModel.Dispatcher.SyncMethodInvoker.Invoke(Object instance, Object[] inputs, Object[]& outputs)
System.ServiceModel.Dispatcher.DispatchOperationRuntime.InvokeBegin(MessageRpc& rpc)
System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage5(MessageRpc& rpc)
System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage31(MessageRpc& rpc)
System.ServiceModel.Dispatcher.MessageRpc.Process(Boolean isOperationContextSet)

Answer 1

这可能与您发送的数据有关。检查您是否发送为空。

编辑

这也可能是一种竞争条件。是否有可能 2 个线程同时使用同一个对象构建查询。如果是这样，您可能会遇到相同参数被添加两次的情况。