WCF 代理连接打开导致错误

Question

我们使用托管在中间层 IIS 上的 WCF 服务并使用 WPF 客户端。 我们在生产日志中看到这些错误。从谷歌我被指向这里的链接http://kennyw.com/indigo/150这清楚地表明此错误与 MaxConcurrentSessions 有关。

下面的生产日志详细信息表明，当 WPF 客户端尝试使用 ICommunicationObject.Open() 打开 WCF 代理连接时，会发生错误 我们的生产系统上的此错误非常频繁地发生，但我无法在本地设置上重现此错误。我尝试将 MaxConcurrentSessions 更改为 1，然后打开 WPF 应用程序的 5 个实例，在 WPF 应用程序上，默认仪表板有一个计时器每 1 分钟运行一次以尝试获取数据，但我仍然无法重现此错误。

我的问题实际上是何时发生此错误，从上面的链接来看，它说当服务器压力过大时会发生这种情况，但在我上面的测试用例中应该已加载。我还需要能够重现此问题，甚至尝试修复。

如果我走在正确的道路上，有什么想法吗？ MaxConcurrentSessions 是否是查看的正确位置以及如何在本地模拟它。请帮忙。

2/16/2012 4:10:40 PM:Information:Exception in the ServiceCall constructor:       System.ServiceModel.CommunicationException: 
  The socket connection was aborted. 
  This could be caused by an error processing your message or a receive timeout being   exceeded by the remote host, or an underlying network resource issue. 
  Local socket timeout was '00:00:59.9687730'. --->System.Net.Sockets.SocketException: 
An existing connection was forcibly closed by the remote host at System.Net.Sockets.Socket.Receive(Byte[] buffer, Int32 offset, Int32 size, SocketFlags socketFlags) at System.ServiceModel.Channels.SocketConnection.ReadCore(Byte[] buffer, Int32 offset, Int32 size, TimeSpan timeout, Boolean closing)
 --- End of inner exception stack trace ---
 Server stack trace: 
 at System.ServiceModel.Channels.SocketConnection.ReadCore(Byte[] buffer, Int32 offset, Int32 size, TimeSpan timeout, Boolean closing)
 at System.ServiceModel.Channels.SocketConnection.Read(Byte[] buffer, Int32 offset, Int32 size, TimeSpan timeout)
 at System.ServiceModel.Channels.DelegatingConnection.Read(Byte[] buffer, Int32 offset, Int32 size, TimeSpan timeout)
 at System.ServiceModel.Channels.ConnectionUpgradeHelper.InitiateUpgrade       (StreamUpgradeInitiator upgradeInitiator, IConnection& connection, ClientFramingDecoder decoder, IDefaultCommunicationTimeouts defaultTimeouts, TimeoutHelper& timeoutHelper)
 at System.ServiceModel.Channels.ClientFramingDuplexSessionChannel.SendPreamble(IConnection connection, ArraySegment`1 preamble, TimeoutHelper& timeoutHelper)
 at  System.ServiceModel.Channels.ClientFramingDuplexSessionChannel.DuplexConnectionPoolHelper.AcceptPooledConnection(IConnection connection, TimeoutHelper& timeoutHelper)
 at System.ServiceModel.Channels.ConnectionPoolHelper.EstablishConnection(TimeSpan timeout)
 at System.ServiceModel.Channels.ClientFramingDuplexSessionChannel.OnOpen(TimeSpan timeout)
 at System.ServiceModel.Channels.CommunicationObject.Open(TimeSpan timeout)
 at System.ServiceModel.Channels.ServiceChannel.OnOpen(TimeSpan timeout)
 at System.ServiceModel.Channels.CommunicationObject.Open(TimeSpan timeout)

Answer 1

问题的根本原因很可能是 WPF 应用程序中服务代理实例的不当处置。查看代理是如何实例化和处置的。

如果您的代码不遵循此 SO question 的答案中描述的模式之一那么你就没有正确释放 TCP 连接。当使用依赖于 TCP session 的绑定(bind)时，此问题最容易出现。