WPF WCF MVVM OutOfMemoryException

Question

I am working on this WCF-WPF app. I am frequently getting this error on an asynchronous XamDataGrid. Trying to make a WCF call and populate the Grid. I initially thought this is something to do with the large amounts of data returned from WCF and I made the call return data is much small pieces, by calling only for a category only. This error comes up randomly, not always on the same set of data. Reproducible enough in 15-20 tries.

I am running Windows XP (32bit), Dual Core, with 4GB of ram. When this exception is raised, client machine only uses about 2GB of RAM, and on the server W3WP is using only 800MB (of 6GB, 3 cores. Total memory use on server is ~2GB).

This is only happening on XP machines. Does not get this error on Windows 7 box.

Please guide me how to resolve this issue.

Thanks in advance

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.

Below id the Exception details:

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.ReliableChannelBinder1.InputAsyncResult1.OnInputComplete(IAsyncResult result) at System.ServiceModel.Channels.ReliableChannelBinder1.InputAsyncResult1.OnInputCompleteStatic(IAsyncResult result) at System.ServiceModel.Diagnostics.Utility.AsyncThunk.UnhandledExceptionFrame(IAsyncResult result) at System.ServiceModel.AsyncResult.Complete(Boolean completedSynchronously) at System.ServiceModel.Channels.InputQueue1.AsyncQueueReader.Set(Item item) at System.ServiceModel.Channels.InputQueue1.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) InnerException:

Answer 1

OK.. found the answer using Sysinternals Process explorer and the StackTrace is right. My POCO generator was going recursively and grabbing all the associated objects, and the size the message back is so large, and due to async loading, the overall requested buffer is going beyond the available memory. As the network buffers cannot use PageFile, it bombs out with this error. It took a while to identify this, as it bombs out on different calls each time, as in the async loading there is no defined order and it could bomb out anytime.