项目中遇到的问题
排查原因
最近调试一个东西，写了个监控页面，发现自己Cache的数据在设定的过期时间远远还没有到的时候就过期了，于是我着手排查了下出现问题的原因：
1、程序会删除缓存 -- 查找了整个项目，发现程序里根本没有删除缓存的操作，所以这个原因可以排除。
2、写缓存的方法有问题 -- 这个也可以排除，因为很多地方用这个dll，其它项目不存在这个bug，所以这个原因也可以排除。
3、服务器上有清除所有内存的程序 -- 于是一个个服务终止了下，最后发现终止了一个动转静服务后，程序就没有异常了，所以这个问题是因为动转静服务引起的了。
解决方案
反编译了这个动转静服务的源码，发现并没有清理内存的操作，于是想到了是不是因为动转静服务的什么操作，引起了应用程序池Appliacation_End，然后cache都被回收了。于是在Global.asax里面的Application_End方法里写了下面的代码，用于记录是否引起了这个事件，以及引起事件触发的原因。
| protected void Application_End(object sender, EventArgs e) { HttpRuntime runtime = (HttpRuntime)typeof(System.Web.HttpRuntime).InvokeMember("_theRuntime", BindingFlags.NonPublic | BindingFlags.Static | BindingFlags.GetField, null, null, null); if (runtime == null) return; string shutDownMessage = (string)runtime.GetType().InvokeMember("_shutDownMessage", BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.GetField, null, runtime, null); string shutDownStack = (string)runtime.GetType().InvokeMember( "_shutDownStack", BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.GetField, null, runtime, null); if (!EventLog.SourceExists(".NETRuntime")) { EventLog.CreateEventSource(".NETRuntime", "Application"); } EventLog log = new EventLog(); log.Source = ".NET Runtime"; log.WriteEntry(String.Format("\r\n\r\n_shutDownMessage={0}\r\n\r\n_shutDownStack={1}", shutDownMessage, shutDownStack), EventLogEntryType.Error); } |
结果，日志文件里头果然有记录，记录都为：
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The description for Event ID ( 0 ) in Source ( .NET Runtime ) cannot be found. The local computer may not have the necessary registry information or message DLL files to display messages from a remote computer. You may be able to use the /AUXSOURCE= flag to retrieve this description; see Help and Support for details. The following information is part of the event:
_shutDownMessage=Recompilation limit of 15 reached
HostingEnvironment initiated shutdown
HostingEnvironment caused shutdown
_shutDownStack= at System.Environment.GetStackTrace(Exception e, Boolean needFileInfo)
at System.Environment.get_StackTrace()
at System.Web.Hosting.HostingEnvironment.InitiateShutdownInternal()
at System.Web.Hosting.HostingEnvironment.InitiateShutdown()
at System.Web.HttpRuntime.ShutdownAppDomain(String stackTrace)
at System.Web.Compilation.DiskBuildResultCache.ShutdownCallBack(Object state)
at System.Threading._ThreadPoolWaitCallback.WaitCallback_Context(Object state)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
at System.Threading._ThreadPoolWaitCallback.PerformWaitCallbackInternal(_ThreadPoolWaitCallback tpWaitCallBack)
at System.Threading._ThreadPoolWaitCallback.PerformWaitCallback(Object state).
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