ASP.NET-MVC(IIS6)高流量时出错：指定的强制转换无效

我刚刚在我简陋的专用服务器(Win2003)上启动了我的 tiny webapp …运行ASP.NET MVC,LINQ2sql,sql Express 2005和IIS6(使用 wildcard mapping设置)

该网站90％的时间运行顺利.但是,在相对较高的流量上,LINQ2sql会抛出错误：
指定演员表无效

此错误仅在高流量时抛出.我没有想法,为什么会发生这种情况.缓存并没有完全消除这个问题.

以前有人见过这个问题吗？是否有任何秘密的sql Server调整我应该做的？
或者至少,关于如何诊断这个问题的任何想法？因为我出去了！

纳伊米

Stacktrace(来自事件日志)：

at System.Data.sqlClient.sqlBuffer.get_sqlGuid()
   at System.Data.sqlClient.sqlDataReader.GetGuid(Int32 i)
   at Read_Friend(ObjectMaterializer`1 )
   at System.Data.Linq.sqlClient.ObjectReaderCompiler.ObjectReader`2.MoveNext()
   at Dudlers.Web.Models.DudlersDataContext.GetFriendRequests(Guid userId) in C:\Web\Models\DudlersDataContext.cs:line 562
   at Dudlers.Web.Controllers.BaseController.View(String viewName,String masterName,Object viewData) in C:\Web\Controllers\BaseController.cs:line 39
   at System.Web.Mvc.Controller.View(String viewName)
   at Dudlers.Web.Controllers.CatController.Index() in C:\Web\Controllers\CatController.cs:line 25
   at lambda_method(ExecutionScope,ControllerBase,Object[] )
   at System.Web.Mvc.ActionMethoddispatcher.Execute(ControllerBase controller,Object[] parameters)
   at System.Web.Mvc.ControllerActionInvoker.InvokeActionMethod(MethodInfo methodInfo,IDictionary`2 parameters)
   at System.Web.Mvc.ControllerActionInvoker.c__displayClassb.b__8()
   at System.Web.Mvc.ControllerActionInvoker.InvokeActionMethodFilter(IActionFilter filter,ActionExecutingContext preContext,Func`1 continuation)
   at System.Web.Mvc.ControllerActionInvoker.c__displayClassb.c__displayClassd.b__a()
   at System.Web.Mvc.ControllerActionInvoker.InvokeActionMethodWithFilters(MethodInfo methodInfo,IDictionary`2 parameters,IList`1 filters)
   at System.Web.Mvc.ControllerActionInvoker.InvokeAction(ControllerContext controllerContext,String actionName)
   at System.Web.Mvc.Controller.ExecuteCore()
   at System.Web.Mvc.ControllerBase.Execute(RequestContext requestContext)
   at System.Web.Mvc.ControllerBase.System.Web.Mvc.IController.Execute(RequestContext requestContext)
   at System.Web.Mvc.MvcHandler.ProcessRequest(HttpContextBase httpContext)
   at System.Web.Mvc.MvcHandler.ProcessRequest(HttpContext httpContext)
   at System.Web.Mvc.MvcHandler.System.Web.IHttpHandler.ProcessRequest(HttpContext httpContext)
   at System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()
   at System.Web.HttpApplication.ExecuteStep(IExecutionStep step,Boolean& completedSynchronously)

解决方法

我们遇到类似LINQ的问题,我们得到“无法将类型’system.int32’的对象强制转换为’System.String’”和“指定的强制转换无效”.

堆栈跟踪的示例

system.invalidCastException: Unable to cast object of type 'system.int32' to type 'System.String'.
   at System.Data.sqlClient.sqlBuffer.get_String()
   at System.Data.sqlClient.sqlDataReader.GetString(Int32 i)
   at Read_Person(ObjectMaterializer`1 )
   at System.Data.Linq.sqlClient.ObjectReaderCompiler.ObjectReader`2.MoveNext()
   at System.Collections.Generic.List`1..ctor(IEnumerable`1 collection)
   at System.Linq.Enumerable.ToList[TSource](IEnumerable`1 source)
   at RF.Ias.Services.Person.BusinessLogic.PersonTransactionScripts.GetPersons(IEnumerable`1 personIds,Boolean includeAddress,Boolean includeContact)
   at CompositionAopProxy_5b0727341ad64f29b816c1b73d11dd44.GetPersons(IEnumerable`1 personIds,Boolean includeContact)
   at RF.Ias.Services.Person.ServiceImplementation.PersonService.GetPersons(GetPersonRequest request)


system.invalidCastException: Specified cast is not valid.
   at System.Data.sqlClient.sqlBuffer.get_Int32()
   at System.Data.sqlClient.sqlDataReader.GetInt32(Int32 i)
   at Read_GetRolesForOrganisationResult(ObjectMaterializer`1 )
   at System.Data.Linq.sqlClient.ObjectReaderCompiler.ObjectReader`2.MoveNext()
   at System.Collections.Generic.List`1..ctor(IEnumerable`1 collection)
   at System.Linq.Enumerable.ToList[TSource](IEnumerable`1 source)
   at RF.Ias.Services.Role.DataAccess.RoleDataAccess.GetRolesForOrganisation(GetRolesForOrganisationCriteria criteria,Int32 pageIndex,Int32 pageSize,Int32& recordCount)
   at RF.Ias.Services.Role.BusinessLogic.RoleTransactionScripts.GetRolesForOrganisation(GetRolesForOrganisationCriteria criteria,Int32& recordCount)
   at CompositionAopProxy_4bd29c6074f54d10a2c09bd4ab27ca66.GetRolesForOrganisation(GetRolesForOrganisationCriteria criteria,Int32& recordCount)
   at RF.Ias.Services.Role.ServiceImplementation.RoleService.GetRolesForOrganisation(GetRolesForOrganisationRequest request)

如果我们第一次得到这样的异常,我们过去会得到这些异常“system.invalidOperationException：已经有一个与此命令关联的开放DataReader,必须先关闭它.”或“从服务器接收结果时发生传输级错误.(提供程序：TCP提供程序,错误：0 – 远程主机强行关闭现有连接.)”.

第一个例外发生在DataCOntext的不同实例上,然后是所有那些随后关注的实例.

经过一些研究并在thread中询问后,我发现原因是我没有处理DataContexts.在我开始这样做之后,它消失了.