症状是挂起的应用程序（在IIS 7中托管） 当使用debuging附加时发现有大约100个带有这样的堆栈的线程：
NLog.dll!NLog.Targets.Target.WriteAsyncLogEvent(NLog.Common.AsyncLogEventInfo logEvent) + 0x54 bytes
NLog.dll!NLog.LoggerImpl.WriteToTargetWithFilterChain(NLog.Internal.TargetWithFilterChain targetListHead, NLog.LogEventInfo logEvent, NLog.Common.AsyncContinuation onException) + 0x8b bytes
NLog.dll!NLog.LoggerImpl.Write(System.Type loggerType, NLog.Internal.TargetWithFilterChain targets, NLog.LogEventInfo logEvent, NLog.LogFactory factory) + 0xee bytes
NLog.dll!NLog.Logger.WriteToTargets(NLog.LogLevel level, string message, object[] args) + 0x14 bytes
NLog.dll!NLog.Logger.Trace<System.__Canon,long>(string message, System.__Canon argument1, long argument2) + 0x90 bytes
... <my app code> ...
一个
mscorlib.dll!System.Collections.Generic.Dictionary<NLog.Layouts.Layout,string>.FindEntry(NLog.Layouts.Layout key) + 0xd0 bytes
mscorlib.dll!System.Collections.Generic.Dictionary<System.__Canon,System.__Canon>.TryGetValue(System.__Canon key, out System.__Canon value) + 0x14 bytes
NLog.dll!NLog.Layouts.SimpleLayout.GetFormattedMessage(NLog.LogEventInfo logEvent) + 0x81 bytes
NLog.dll!NLog.Targets.FileTarget.GetBytesToWrite(NLog.LogEventInfo logEvent) + 0x1c bytes
NLog.dll!NLog.Targets.FileTarget.Write(NLog.Common.AsyncLogEventInfo[] logEvents) + 0x308 bytes
NLog.dll!NLog.Targets.Target.WriteAsyncLogEvents(NLog.Common.AsyncLogEventInfo[] logEvents) + 0x258 bytes
NLog.dll!NLog.Targets.Wrappers.AsyncTargetWrapper.ProcessPendingEvents(object state) + 0x1e6 bytes
mscorlib.dll!System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext executionContext, System.Threading.ContextCallback callback, object state, bool ignoreSyncCtx) + 0xdc bytes
mscorlib.dll!System.Threading._TimerCallback.PerformTimerCallback(object state) + 0x97 bytes
... <my app code> ...
和一个
mscorlib.dll!System.Collections.Generic.Dictionary<NLog.Layouts.Layout,string>.Insert(NLog.Layouts.Layout key, string value, bool add) + 0x1e0 bytes
NLog.dll!NLog.LogEventInfo.AddCachedLayoutValue(NLog.Layouts.Layout layout, string value) + 0x6c bytes
NLog.dll!NLog.Layouts.Log4JXmlEventLayout.GetFormattedMessage(NLog.LogEventInfo logEvent) + 0xf5 bytes
NLog.dll!NLog.Targets.Target.PrecalculateVolatileLayouts(NLog.LogEventInfo logEvent) + 0xb8 bytes
NLog.dll!NLog.Targets.Wrappers.AsyncTargetWrapper.Write(NLog.Common.AsyncLogEventInfo logEvent) + 0x23 bytes
NLog.dll!NLog.Targets.Target.WriteAsyncLogEvent(NLog.Common.AsyncLogEventInfo logEvent) + 0x151 bytes
NLog.dll!NLog.LoggerImpl.WriteToTargetWithFilterChain(NLog.Internal.TargetWithFilterChain targetListHead, NLog.LogEventInfo logEvent, NLog.Common.AsyncContinuation onException) + 0x8b bytes
NLog.dll!NLog.LoggerImpl.Write(System.Type loggerType, NLog.Internal.TargetWithFilterChain targets, NLog.LogEventInfo logEvent, NLog.LogFactory factory) + 0xee bytes
NLog.dll!NLog.Logger.WriteToTargets(NLog.LogLevel level, string message, object[] args) + 0x14 bytes
NLog.dll!NLog.Logger.Debug<Werp.Controller.Common.Interfaces.EntityEventAction,System.__Canon>(string message, Werp.Controller.Common.Interfaces.EntityEventAction argument1, System.__Canon argument2) + 0x8d bytes
... <my app code> ...
这种情况有时会发生，可能是一周一次，而且我没有exac场景来重现它。
我该如何解决这个问题？是NLog中的错误，还是我的一些误用或配置错误？
答案 0 :(得分：1)
Dictionary<T>不是线程安全的，因此在多个线程中访问它可能会导致此类问题，
http://msdn.microsoft.com/en-us/library/xfhwa508.aspx
很难判断您是否可以将NLog配置为在多线程中工作。您是否尝试使用其AsyncWrapper？
http://nlog-project.org/wiki/AsyncWrapper_target
根据NLog论坛，使用异步方式应解决问题，
http://nlog-forum.1685105.n2.nabble.com/Multi-Threading-in-NLog-td3728834.html
答案 1 :(得分：1)
我最近遇到了同样的问题 - 在WriteAsyncLogEvent上阻塞了很多线程。我没有任何Dictionary个帖子。我在AsyncRequestQueue.Enqueue中遇到了一个线程，你可能在线程列表中遗漏了这个线程。
就我而言，问题是overflowAction上的AsyncWrapper设置为... Block！将其设置为Discard是处理过载记录器的更明智的方法。
有时日志消息会累积，因为NLog本身没有故障。有时，由于其他原因（磁盘阻塞，大量交换，防病毒混乱，完整GC），进程卡住了。然后，线程列表包含大量固定在NLog上的线程，因为NLog恰好依赖于相同的重载资源。