为什么log4net线程会等待？

上周，我们的一个测试服务器用完了日志驱动器上的磁盘空间 . 在释放磁盘空间后，我仍然有几个带调用堆栈的线程似乎被卡在log4net AppenderSkeleton.DoAppend中，这让我感到困惑，因为我期望log4net是线程安全的 .

• 我是否正确看到线程被卡住了？

• 堆栈是否表示线程卡在'lock(this)'或其他地方？我的猜测在其他地方，因为我希望看到像Monitor.Enter这样的东西，如果它被锁定（这个） .

• 其中一个主题似乎在翻转到新文件的过程中显示DoAppend . 是否可以在创建此文件时阻止所有DoAppend线程？但是，我希望在释放磁盘空间后，这些线程会被解除阻塞 .

Any help understanding why log4net seems to be stuck across so many threads is appreciated.

下面是一个示例调用堆栈，显示在DoAppend内等待时阻塞的线程：

ntdll.dll!_NtWaitForMultipleObjects@20（）0x15字节ntdll.dll！_NtWaitForMultipleObjects@20（）0x15字节KERNELBASE.dll!_WaitForMultipleObjectsEx@20（）0x36字节kernel32.dll！_WaitForMultipleObjectsExImplementation@20（）0x8e字节[管理到本机转换] log4net.dll！log4net.Appender.AppenderSkeleton.DoAppend（log4net.Core.LoggingEvent loggingEvent）0x3e bytes log4net.dll！log4net.Util.AppenderAttachedImpl.AppendLoopOnAppenders（log4net.Core.LoggingEvent loggingEvent）0xa0 bytes log4net.dll！log4net.Repository .Hierarchy.Logger.CallAppenders（log4net.Core.LoggingEvent loggingEvent）0xa9 bytes log4net.dll！log4net.Repository.Hierarchy.Logger.ForcedLog（System.Type callerStackBoundaryDeclaringType，log4net.Core.Level level，object message，System.Exception exception） 0x4a bytes log4net.dll！log4net.Repository.Hierarchy.Logger.Log（System.Type callerStackBoundaryDeclaringType，log4net.Core.Level level，object message，System.Exception exception）0x5e bytes log4net.dll！log4n et.Core.LogImpl.Info（对象消息）0x27字节

这是log4net AppenderSkeleton.DoAppend的源代码

public void DoAppend(LoggingEvent loggingEvent) 
{
    // This lock is absolutely critical for correct formatting
    // of the message in a multi-threaded environment.  Without
    // this, the message may be broken up into elements from
    // multiple thread contexts (like get the wrong thread ID).

    lock(this)
    {
        if (m_closed)
        {
            ErrorHandler.Error("Attempted to append to closed appender named ["+m_name+"].");
            return;
        }

        // prevent re-entry
        if (m_recursiveGuard)
        {
            return;
        }

        try
        {
            m_recursiveGuard = true;

            if (FilterEvent(loggingEvent) && PreAppendCheck())
            {
                this.Append(loggingEvent);
            }
        }
        catch(Exception ex)
        {
            ErrorHandler.Error("Failed in DoAppend", ex);
        }
#if !MONO && !NET_2_0
        // on .NET 2.0 (and higher) and Mono (all profiles), 
        // exceptions that do not derive from System.Exception will be
        // wrapped in a RuntimeWrappedException by the runtime, and as
        // such will be catched by the catch clause above
        catch
        {
            // Catch handler for non System.Exception types
            ErrorHandler.Error("Failed in DoAppend (unknown exception)");
        }
#endif
        finally
        {
            m_recursiveGuard = false;
        }
    }
}

这是我的log4net设置：

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
  <configSections>
    <section name="log4net" type="log4net.Config.Log4NetConfigurationSectionHandler,log4net" />
  </configSections>
  <log4net xsi:noNamespaceSchemaLocation="log4net.xsd" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
    <appender name="RollingFileAppender" type="log4net.Appender.RollingFileAppender">
      <file value="g:\logfiles\mySerivceName\" />
      <appendToFile value="true" />
      <rollingStyle value="Date" />
      <datePattern value="'myServiceName.'yyyy-MM-dd-HH'-00.log'"/>
      <staticLogFileName value="false" />
      <layout type="log4net.Layout.PatternLayout">
        <conversionPattern value="%date{yyyy-MM-dd HH:mm:ss.fff} %-5level [%3thread] [%-50.50stacktrace] %message %newline"/>
      </layout>
      <filter type="log4net.Filter.LevelRangeFilter">
        <levelMin value="INFO" />
        <levelMax value="FATAL" />
      </filter>
    </appender>
    <appender name="SmtpAppender" type="log4net.Appender.SmtpAppender">
        <to value="alerts@myCompanyName.com" />
        <from value="servicename@localnetwork" />
        <subject value="${COMPUTERNAME} - Error Generated" />
        <smtpHost value="mySmtpServerIpAddress" />
        <bufferSize value="2" />
        <lossy value="true" />
        <layout type="log4net.Layout.PatternLayout">
            <conversionPattern value="%date{yyyy-MM-dd HH:mm:ss.fff} %-5level [%3thread] [%-50.50stacktrace] %message %newline" />
        </layout>
        <filter type="log4net.Filter.LevelRangeFilter">
            <levelMin value="ERROR" />
            <levelMax value="FATAL" />
        </filter>
    </appender>
    <root>
      <level value="DEBUG"/>
      <appender-ref ref="RollingFileAppender" />
    </root>
  </log4net>
</configuration>

The DoAppend stack that is rolling over to a new file

mscorlib.dll！System.Text.StringBuilder.Append（char value）第953行0xb字节
mscorlib.dll！System.IO.PathHelper.Append（char value）第139行0x18字节
mscorlib.dll！System.IO.Path.NormalizePath（string path，bool fullCheck，int maxPathLength，bool expandShortPaths）620行
mscorlib.dll！System.IO.Path.GetDirectoryName（字符串路径）第170行0x24字节
log4net.dll！log4net.Appender.FileAppender.LockingModelBase.CreateStream（string filename，bool append，System.IO.FileShare fileShare）0x35 bytes
log4net.dll！log4net.Appender.FileAppender.ExclusiveLock.OpenFile（string filename，bool append，System.Text.Encoding encoding）0x2d bytes
log4net.dll！log4net.Appender.FileAppender.OpenFile（string fileName，bool append）0x1ac bytes
log4net.dll！log4net.Appender.RollingFileAppender.OpenFile（string fileName，bool append）0x189 bytes
log4net.dll！log4net.Appender.FileAppender.SafeOpenFile（string fileName，bool append）0x2d bytes
log4net.dll！log4net.Appender.FileAppender.PrepareWriter（）0x13字节
log4net.dll！log4net.Appender.TextWriterAppender.PreAppendCheck（）0x32字节
log4net.dll！log4net.Appender.AppenderSkeleton.DoAppend（log4net.Core.LoggingEvent loggingEvent）0xe0 bytes
log4net.dll！log4net.Util.AppenderAttachedImpl.AppendLoopOnAppenders（log4net.Core.LoggingEvent loggingEvent）0xa0 bytes
log4net.dll！log4net.Repository.Hierarchy.Logger.CallAppenders（log4net.Core.LoggingEvent loggingEvent）0xa9 bytes
log4net.dll！log4net.Repository.Hierarchy.Logger.ForcedLog（System.Type callerStackBoundaryDeclaringType，log4net.Core.Level level，object message，System.Exception exception）0x4a bytes
log4net.dll！log4net.Repository.Hierarchy.Logger.Log（System.Type callerStackBoundaryDeclaringType，log4net.Core.Level level，object message，System.Exception exception）0x5e bytes
log4net.dll！log4net.Core.LogImpl.Info（对象消息）0x27字节

这是同一台机器上的另一个调用堆栈，不同的进程，也挂起：

clr.dll！AwareLock :: Contention（）0x10d bytes [管理到本机转换] log4net.dll！log4net.Appender.AppenderSkeleton.DoAppend（log4net.Core.LoggingEvent loggingEvent）0x3e bytes log4net.dll！log4net.Util.AppenderAttachedImpl . AppendLoopOnAppenders（log4net.Core.LoggingEvent loggingEvent）0xa0字节log4net.dll！log4net.Repository.Hierarchy.Logger.CallAppenders（log4net.Core.LoggingEvent loggingEvent）0xa9 bytes log4net.dll！log4net.Repository.Hierarchy.Logger.ForcedLog（System.Type callerStackBoundaryDeclaringType，log4net.Core.Level level，object消息，System.Exception异常）0x4a bytes log4net.dll！log4net.Repository.Hierarchy.Logger.Log（System.Type callerStackBoundaryDeclaringType，log4net.Core.Level level，object message，System.Exception exception）0x5e bytes log4net.dll！log4net .Core.LogImpl.Info（对象消息）0x27字节

在同一台机器上的第二个进程中，还有一个线程似乎被阻止尝试翻转 .

MSVCR120_CLR0400.dll！_memcpy（）0x21e bytes [管理到本机转换] mscorlib.dll！System.Buffer._Memcpy（byte * dest，byte * src，int len）行484 0x20字节C＃mscorlib.dll！System.Buffer . Memcpy（byte * dest，byte * src，int len）第401行C＃mscorlib.dll！string.FillStringChecked（string dest，int destPos，string src）第1523行0xf字节C＃mscorlib.dll！string.ConcatArray（string [] values ，int totalLength）第3340行C＃mscorlib.dll！string.Concat（object [] args）第3180行0xa字节C＃log4net.dll！log4net.Appender.FileAppender.OpenFile（字符串fileName，bool追加）0x162字节log4net.dll！log4net .Appender.RollingFileAppender.OpenFile（string fileName，bool append）0x189 bytes log4net.dll！log4net.Appender.FileAppender.SafeOpenFile（string fileName，bool append）0x2d bytes log4net.dll！log4net.Appender.FileAppender.PrepareWriter（）0x13 bytes log4net.dll！log4net.Appender.TextWriterAppender.PreAppendCheck（）0x32 bytes log4net.dll！log4net.Appender.AppenderSkeleton.DoAppend（log4ne t.Core.LoggingEvent loggingEvent）0xe0 bytes log4net.dll！log4net.Util.AppenderAttachedImpl.AppendLoopOnAppenders（log4net.Core.LoggingEvent loggingEvent）0xa0 bytes log4net.dll！log4net.Repository.Hierarchy.Logger.CallAppenders（log4net.Core.LoggingEvent loggingEvent ）0xa9 bytes log4net.dll！log4net.Repository.Hierarchy.Logger.ForcedLog（System.Type callerStackBoundaryDeclaringType，log4net.Core.Level level，object message，System.Exception exception）0x4a bytes log4net.dll！log4net.Repository.Hierarchy.Logger .Log（System.Type callerStackBoundaryDeclaringType，log4net.Core.Level level，object message，System.Exception exception）0x5e bytes log4net.dll！log4net.Core.LogImpl.Info（object message）0x27 bytes