c# - 如何修复 Azure redis 缓存中的超时异常？

Question

我们有一个使用 Microsoft.Web.Redis.RedisSessionStateProvider 作为 session 状态提供程序的 Web 应用程序。我们在这方面没有遇到任何问题，直到最近应用程序突然报告大量异常，如下所述。

该消息表明存在某种超时。但我不知道如何解决这个问题。该应用程序是 Kentico CMS 的一个实例，我们没有以任何方式定制其 session 缓存机制。

主要异常(exception):

消息:

Exception of type 'System.Web.HttpException' was thrown.

堆栈跟踪:

at System.Web.HttpAsyncResult.End() 
at System.Web.HttpApplication.AsyncEventExecutionStep.OnAsyncEventCompletion(IAsyncResult ar) 

内部异常:

消息:

Timeout performing EVAL, inst: 1, mgr: Inactive, err: never, queue: 0, qu: 0, qs: 0, qc: 0, wr: 0, wq: 0, in: 0, ar: 0, IOCP: (Busy=0,Free=1000,Min=2,Max=1000), WORKER: (Busy=3,Free=32764,Min=2,Max=32767), clientName: KSCOMAZUATWEB2

堆栈跟踪:

at StackExchange.Redis.ConnectionMultiplexer.ExecuteSyncImpl[T](Message message, ResultProcessor`1 processor, ServerEndPoint server) in c:\TeamCity\buildAgent\work\3ae0647004edff78\StackExchange.Redis\StackExchange\Redis\ConnectionMultiplexer.cs:line 1927 
at StackExchange.Redis.RedisBase.ExecuteSync[T](Message message, ResultProcessor`1 processor, ServerEndPoint server) in c:\TeamCity\buildAgent\work\3ae0647004edff78\StackExchange.Redis\StackExchange\Redis\RedisBase.cs:line 80 
at StackExchange.Redis.RedisDatabase.ScriptEvaluate(String script, RedisKey[] keys, RedisValue[] values, CommandFlags flags) in c:\TeamCity\buildAgent\work\3ae0647004edff78\StackExchange.Redis\StackExchange\Redis\RedisDatabase.cs:line 866 
at Microsoft.Web.Redis.StackExchangeClientConnection.<>c__DisplayClass4.<Eval>b__3() in d:\TeamCityBuildAgent\work\f55792526e6d9089\src\Shared\StackExchangeClientConnection.cs:line 113 
at Microsoft.Web.Redis.StackExchangeClientConnection.RetryForScriptNotFound(Func`1 redisOperation) in d:\TeamCityBuildAgent\work\f55792526e6d9089\src\Shared\StackExchangeClientConnection.cs:line 129 
at Microsoft.Web.Redis.StackExchangeClientConnection.RetryLogic(Func`1 redisOperation) in d:\TeamCityBuildAgent\work\f55792526e6d9089\src\Shared\StackExchangeClientConnection.cs:line 155 
at Microsoft.Web.Redis.StackExchangeClientConnection.Eval(String script, String[] keyArgs, Object[] valueArgs) in d:\TeamCityBuildAgent\work\f55792526e6d9089\src\Shared\StackExchangeClientConnection.cs:line 113 
at Microsoft.Web.Redis.RedisConnectionWrapper.TryTakeWriteLockAndGetData(DateTime lockTime, Int32 lockTimeout, Object& lockId, ISessionStateItemCollection& data, Int32& sessionTimeout) in d:\TeamCityBuildAgent\work\f55792526e6d9089\src\RedisSessionStateProvider\RedisConnectionWrapper.cs:line 182 
at Microsoft.Web.Redis.RedisSessionStateProvider.GetItemFromSessionStore(Boolean isWriteLockRequired, HttpContext context, String id, Boolean& locked, TimeSpan& lockAge, Object& lockId, SessionStateActions& actions) in d:\TeamCityBuildAgent\work\f55792526e6d9089\src\RedisSessionStateProvider\RedisSessionStateProvider.cs:line 272 
at Microsoft.Web.Redis.RedisSessionStateProvider.GetItemExclusive(HttpContext context, String id, Boolean& locked, TimeSpan& lockAge, Object& lockId, SessionStateActions& actions) in d:\TeamCityBuildAgent\work\f55792526e6d9089\src\RedisSessionStateProvider\RedisSessionStateProvider.cs:line 190 
at System.Web.SessionState.SessionStateModule.GetSessionStateItem() 
at System.Web.SessionState.SessionStateModule.PollLockedSessionCallback(Object state) 

Answer 1

在遇到相同的问题并阅读有关设置最小和最大线程值等的各种帖子后，发现问题出在订阅层上。

C1 基本版(每月 35 英镑/英镑)拥有 1GB 缓存、1000 个并发连接，这与 C1 标准层(每月 95 英镑/英镑)的标题数字完全相同。这是一个自然的假设，即当您只需要几 MB 的缓存并且在任何时候只有 50 个并发 session 处于事件状态时，C!基本的就足够了，如果不是过度的话。

区别似乎在于，如果您的网站上有 10 个或更少的并发用户，则 C1 Basic 可以工作。平心而论，细则中提到了basic只适合开发和测试环境。