Question

我正在研究这款WCF-WPF应用。我经常在异步XamDataGrid上收到此错误。尝试进行WCF调用并填充网格。我最初认为这与从WCF返回的大量数据有关，我通过仅调用类别来使调用返回数据变得非常小。此错误随机出现，并不总是在同一组数据上。可以在15-20次尝试中重现。

我正在运行Windows XP（32位），双核，4GB内存。引发此异常时，客户端计算机仅使用大约2GB的RAM，而在服务器上W3WP仅使用800MB（6GB，3个核心。服务器上的总内存使用量约为2GB）。

这只发生在XP机器上。在Windows 7上没有出现此错误。

请指导我如何解决此问题。

提前致谢

Event Viewer Logs this Message:
Event Type: Error
Event Source:   .NET Runtime 2.0 Error Reporting
Event Category: None
Event ID:   5000
Date:       10/13/2010
Time:       10:50:07 AM
User:       N/A
Computer:   COMP-DC7800
Description:
EventType clr20r3, P1 appname.exe, P2 2.0.0.21872, P3 4cb0a1b1, P4 mscorlib, P5 2.0.0.0, P6 492b834a, P7 35df, P8 45, P9 system.outofmemoryexception, P10 NIL.

下面是ID异常详情：

System.OutOfMemoryException was unhandled
Message="Exception of type 'System.OutOfMemoryException' was thrown."
Source="mscorlib"
StackTrace:
   at System.IO.MemoryStream.set_Capacity(Int32 value)
   at System.IO.MemoryStream.EnsureCapacity(Int32 value)
   at System.IO.MemoryStream.Write(Byte[] buffer, Int32 offset, Int32 count)
   at System.Xml.XmlMtomReader.MimePart.GetBuffer(Int32 maxBuffer, Int32& remaining)
   at System.Xml.XmlMtomReader.Initialize(Stream stream, String contentType, XmlDictionaryReaderQuotas quotas, Int32 maxBufferSize)
   at System.Xml.XmlMtomReader.SetInput(Stream stream, Encoding[] encodings, String contentType, XmlDictionaryReaderQuotas quotas, Int32 maxBufferSize, OnXmlDictionaryReaderClose onClose)
   at System.Xml.XmlMtomReader.SetInput(Byte[] buffer, Int32 offset, Int32 count, Encoding[] encodings, String contentType, XmlDictionaryReaderQuotas quotas, Int32 maxBufferSize, OnXmlDictionaryReaderClose onClose)
   at System.ServiceModel.Channels.MtomMessageEncoder.MtomBufferedMessageData.TakeXmlReader()
   at System.ServiceModel.Channels.BufferedMessageData.DoTakeXmlReader()
   at System.ServiceModel.Channels.BufferedMessageData.GetMessageReader()
   at System.ServiceModel.Channels.MessageHeaders.GetBufferedMessageHeaderReaderAtHeaderContents(IBufferedMessageData bufferedMessageData)
   at System.ServiceModel.Channels.MessageHeaders.GetBufferedMessageHeaderReader(IBufferedMessageData bufferedMessageData, Int32 bufferedMessageHeaderIndex)
   at System.ServiceModel.Channels.MessageHeaders.GetReaderAtHeader(Int32 headerIndex)
   at System.ServiceModel.Channels.WsrmMessageInfo.Get(MessageVersion messageVersion, ReliableMessagingVersion reliableMessagingVersion, IChannel channel, ISession session, Message message, Boolean csrOnly)
   at System.ServiceModel.Channels.ReliableDuplexSessionChannel.HandleReceiveComplete(IAsyncResult result)
   at System.ServiceModel.Channels.ReliableDuplexSessionChannel.OnReceiveCompletedStatic(IAsyncResult result)
   at System.ServiceModel.Diagnostics.Utility.AsyncThunk.UnhandledExceptionFrame(IAsyncResult result)
   at System.ServiceModel.AsyncResult.Complete(Boolean completedSynchronously)
   at System.ServiceModel.Channels.ReliableChannelBinder`1.InputAsyncResult`1.OnInputComplete(IAsyncResult result)
   at System.ServiceModel.Channels.ReliableChannelBinder`1.InputAsyncResult`1.OnInputCompleteStatic(IAsyncResult result)
   at System.ServiceModel.Diagnostics.Utility.AsyncThunk.UnhandledExceptionFrame(IAsyncResult result)
   at System.ServiceModel.AsyncResult.Complete(Boolean completedSynchronously)
   at System.ServiceModel.Channels.InputQueue`1.AsyncQueueReader.Set(Item item)
   at System.ServiceModel.Channels.InputQueue`1.Dispatch()
   at System.ServiceModel.Channels.InputQueue`1.OnDispatchCallback(Object state)
   at System.ServiceModel.Channels.IOThreadScheduler.CriticalHelper.WorkItem.Invoke2()
   at System.ServiceModel.Channels.IOThreadScheduler.CriticalHelper.WorkItem.OnSecurityContextCallback(Object o)
   at System.Security.SecurityContext.Run(SecurityContext securityContext, ContextCallback callback, Object state)
   at System.ServiceModel.Channels.IOThreadScheduler.CriticalHelper.WorkItem.Invoke()
   at System.ServiceModel.Channels.IOThreadScheduler.CriticalHelper.ProcessCallbacks()
   at System.ServiceModel.Channels.IOThreadScheduler.CriticalHelper.CompletionCallback(Object state)
   at System.ServiceModel.Channels.IOThreadScheduler.CriticalHelper.ScheduledOverlapped.IOCallback(UInt32 errorCode, UInt32 numBytes, NativeOverlapped* nativeOverlapped)
   at System.ServiceModel.Diagnostics.Utility.IOCompletionThunk.UnhandledExceptionFrame(UInt32 error, UInt32 bytesRead, NativeOverlapped* nativeOverlapped)
   at System.Threading._IOCompletionCallback.PerformIOCompletionCallback(UInt32 errorCode, UInt32 numBytes, NativeOverlapped* pOVERLAP)

Answer 1

OutOfMemory异常可能由于很多原因而发生，特别是在Web应用程序中。

首先，如果您在IIS上运行，则有一些特定于IIS的设置来限制内存，请参阅此处：http://blogs.msdn.com/b/pfedev/archive/2009/01/22/memory-based-recycling-in-iis-6-0.aspx

根据您的配置，池等，这些限制可能不适用于.NET Web应用程序。

现在，在ASP.NET中， machine.config 文件中还有一个设置 memoryLimit ，它指定允许的最大内存大小，占整个系统的百分比内存，工作进程在ASP.NET启动新进程并重新分配现有请求之前可以使用的内存。

默认值为60％，在2G机器上等于1.2G。

但是，......无论您配置什么，800M是32位计算机上ASP.NET应用程序的实际限制，请在此处查看一个很好的解释：Understanding ASP.Net memory

避免这种情况的解决方案是改变系统的工作方式并将其分解为更小的部分。

这就是为什么默认情况下，WCF已经仔细配置了这么多限制（请参阅此处有一个广泛的列表：http://weblogs.asp.net/paolopia/archive/2008/03/23/wcf-configuration-default-limits-concurrency-and-scalability.aspx）...几乎每个开发人员都会在发现后立即改变和最大限度它： - ）

Answer 2

对于32位操作系统，您将无法使用4 GB的RAM。

http://chris.pirillo.com/32-bit-windows-and-4gb-of-ram/

如果您的应用程序在使用时占用的内存越来越多，您可能需要查看内存管理。查看为具有非托管资源的类实现IDisposable接口。此外，避免在完成对象使用后保留对对象的引用。事件对此尤其不利。

How do events cause memory leaks in C# and how do Weak References help mitigate that?

您还可以查看流式传输到临时文件而不是流式传输到内存。

WPF WCF MVVM OutOfMemoryException

3 个答案: