Azure Redis Cache - Multiple errors TimeoutException: Timeout performing GET {key}

问题

We deployed our application to Azure. It is using the Azure Redis Cache and we are experiencing quite a few timeouts. Namely:

[TimeoutException: Timeout performing GET textobjectDetails__23290_TextObject, inst: 1, mgr: Inactive, queue: 5, qu=0, qs=5, qc=0, wr=0/0, in=56864/0]

[TimeoutException: Timeout performing GET featured_series_CachedSeries, inst: 1, mgr: Inactive, queue: 4, qu=0, qs=4, qc=0, wr=0/0, in=44470/0]

[TimeoutException: Timeout performing GET SeriesByFranchiseId_1_CachedSeries, inst: 1, mgr: Inactive, queue: 3, qu=0, qs=3, qc=0, wr=0/0, in=11252/0]

[TimeoutException: Timeout performing GET media_silo-1-1-0_Media, inst: 1, mgr: Inactive, queue: 3, qu=0, qs=3, qc=0, wr=0/0, in=15188/0]

[TimeoutException: Timeout performing GET textobjectDetails__3092_TextObject, inst: 3, mgr: Inactive, queue: 7, qu=0, qs=7, qc=0, wr=0/0, in=65536/0]

[TimeoutException: Timeout performing GET textobjectbytype_104__TextObject, inst: 11, mgr: Inactive, queue: 9, qu=0, qs=9, qc=0, wr=0/0, in=65536/0]

[TimeoutException: Timeout performing GET groupnews_2_14_TextObject, inst: 1, mgr: Inactive, queue: 7, qu=0, qs=7, qc=0, wr=0/0, in=65536/0]

[TimeoutException: Timeout performing GET archived_news_by_group_13586_1_TextObject, inst: 2, mgr: Inactive, queue: 7, qu=0, qs=7, qc=0, wr=0/0, in=65536/0]

[TimeoutException: Timeout performing GET textobjectDetails__24404_TextObject, inst: 11, mgr: Inactive, queue: 12, qu=0, qs=12, qc=0, wr=0/0, in=65536/0]

[TimeoutException: Timeout performing GET standings_232_lcds_fixtures, inst: 2, mgr: Inactive, queue: 11, qu=0, qs=11, qc=0, wr=0/0, in=65536/0]

[TimeoutException: Timeout performing GET player_name1099_Player, inst: 4, mgr: Inactive, queue: 11, qu=0, qs=11, qc=0, wr=0/0, in=65536/0]

[TimeoutException: Timeout performing GET groupnews_1_6_TextObject, inst: 4, mgr: Inactive, queue: 9, qu=0, qs=9, qc=0, wr=0/0, in=65536/0]

[TimeoutException: Timeout performing GET archivednewscount__20789_TextObject, inst: 2, mgr: Inactive, queue: 11, qu=0, qs=11, qc=0, wr=0/0, in=65536/0]

[TimeoutException: Timeout performing GET media_id3648_Media, inst: 1, mgr: Inactive, queue: 10, qu=0, qs=10, qc=0, wr=0/0, in=65536/0]

The body of the exception is the same for all of them:

StackExchange.Redis.ConnectionMultiplexer.ExecuteSyncImpl[T](Message message, ResultProcessor`1 processor, ServerEndPoint server):509
    StackExchange.Redis.RedisBase.ExecuteSync[T](Message message, ResultProcessor`1 processor, ServerEndPoint server):25
    StackExchange.Redis.RedisDatabase.StringGet(RedisKey key, CommandFlags flags):16
    AB.SiteCaching.Providers.RedisDataSource+<>c__DisplayClasse`1.<RetrieveCacheObject>b__b():0
    Microsoft.Practices.TransientFaultHandling.RetryPolicy.ExecuteAction[TResult](Func`1 func):115
    AB.SiteCaching.Providers.RedisDataSource.RetrieveCacheObject[T](String fullCacheKey):56
    AB.SiteCaching.Providers.RedisDataSource.RetrieveCached[T](String key, Func`1 onNotCached, TimeSpan timeOut):61
    DataAccess.Data.Caching.CachedSeries.GetSeriesByFranchiseId(Int32 franchiseId):64
    Shared.Services.SeriesService.LatestYearByFranchiseId(Int32 franchiseId):0
    AllBlacksdotcom.Controllers.FixturesController._MostRecentYearOfFixtures(Int32 franchiseId):0
    (unknown).lambda_method(Closure , ControllerBase , Object[] ):-1
    System.Web.Mvc.ActionMethodDispatcher.Execute(ControllerBase controller, Object[] parameters):0
    System.Web.Mvc.ReflectedActionDescriptor.Execute(ControllerContext controllerContext, IDictionary`2 parameters):87
    System.Web.Mvc.ControllerActionInvoker.InvokeActionMethod(ControllerContext controllerContext, ActionDescriptor actionDescriptor, IDictionary`2 parameters):0
    System.Web.Mvc.Async.AsyncControllerActionInvoker.<BeginInvokeSynchronousActionMethod>b__39(IAsyncResult asyncResult, ActionInvocation innerInvokeState):0
    System.Web.Mvc.Async.AsyncResultWrapper+WrappedAsyncResult`2.CallEndDelegate(IAsyncResult asyncResult):0
    System.Web.Mvc.Async.AsyncResultWrapper+WrappedAsyncResultBase`1.End():41
    System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeActionMethod(IAsyncResult asyncResult):0
    System.Web.Mvc.Async.AsyncControllerActionInvoker+AsyncInvocationWithFilters.<InvokeActionMethodFilterAsynchronouslyRecursive>b__3d():20
    System.Web.Mvc.Async.AsyncControllerActionInvoker+AsyncInvocationWithFilters+<>c__DisplayClass46.<InvokeActionMethodFilterAsynchronouslyRecursive>b__3f():134
    System.Web.Mvc.Async.AsyncControllerActionInvoker+<>c__DisplayClass33.<BeginInvokeActionMethodWithFilters>b__32(IAsyncResult asyncResult):0
    System.Web.Mvc.Async.AsyncResultWrapper+WrappedAsyncResult`1.CallEndDelegate(IAsyncResult asyncResult):0
    System.Web.Mvc.Async.AsyncResultWrapper+WrappedAsyncResultBase`1.End():41
    System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeActionMethodWithFilters(IAsyncResult asyncResult):0
    System.Web.Mvc.Async.AsyncControllerActionInvoker+<>c__DisplayClass21+<>c__DisplayClass2b.<BeginInvokeAction>b__1c():0
    System.Web.Mvc.Async.AsyncControllerActionInvoker+<>c__DisplayClass21.<BeginInvokeAction>b__1e(IAsyncResult asyncResult):65
    System.Web.Mvc.Async.AsyncResultWrapper+WrappedAsyncResult`1.CallEndDelegate(IAsyncResult asyncResult):0
    System.Web.Mvc.Async.AsyncResultWrapper+WrappedAsyncResultBase`1.End():41
    System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeAction(IAsyncResult asyncResult):0
    System.Web.Mvc.Controller.<BeginExecuteCore>b__1d(IAsyncResult asyncResult, ExecuteCoreState innerState):0
    System.Web.Mvc.Async.AsyncResultWrapper+WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult):0
    System.Web.Mvc.Async.AsyncResultWrapper+WrappedAsyncResultBase`1.End():41
    System.Web.Mvc.Controller.EndExecuteCore(IAsyncResult asyncResult):0
    System.Web.Mvc.Controller.<BeginExecute>b__15(IAsyncResult asyncResult, Controller controller):0
    System.Web.Mvc.Async.AsyncResultWrapper+WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult):0
    System.Web.Mvc.Async.AsyncResultWrapper+WrappedAsyncResultBase`1.End():41
    System.Web.Mvc.Controller.EndExecute(IAsyncResult asyncResult):0
    System.Web.Mvc.Controller.System.Web.Mvc.Async.IAsyncController.EndExecute(IAsyncResult asyncResult):0
    System.Web.Mvc.MvcHandler.<BeginProcessRequest>b__5(IAsyncResult asyncResult, ProcessRequestState innerState):0
    System.Web.Mvc.Async.AsyncResultWrapper+WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult):0
    System.Web.Mvc.Async.AsyncResultWrapper+WrappedAsyncResultBase`1.End():41
    System.Web.Mvc.MvcHandler.EndProcessRequest(IAsyncResult asyncResult):0
    System.Web.Mvc.MvcHandler.System.Web.IHttpAsyncHandler.EndProcessRequest(IAsyncResult result):0
    System.Web.Mvc.HttpHandlerUtil+ServerExecuteHttpHandlerAsyncWrapper+<>c__DisplayClassa.<EndProcessRequest>b__9():0
    System.Web.Mvc.HttpHandlerUtil+ServerExecuteHttpHandlerWrapper+<>c__DisplayClass4.<Wrap>b__3():0
    System.Web.Mvc.HttpHandlerUtil+ServerExecuteHttpHandlerWrapper.Wrap[TResult](Func`1 func):0
    System.Web.Mvc.HttpHandlerUtil+ServerExecuteHttpHandlerWrapper.Wrap(Action action):25
    System.Web.Mvc.HttpHandlerUtil+ServerExecuteHttpHandlerAsyncWrapper.EndProcessRequest(IAsyncResult result):32
    System.Web.HttpServerUtility.ExecuteInternal(IHttpHandler handler, TextWriter writer, Boolean preserveForm, Boolean setPreviousPage, VirtualPath path, VirtualPath filePath, String physPath, Exception error, String queryStringOverride):772

Please see our time-out settings:

retryTimeoutInMilliseconds = "5000" 
connectionTimeoutInMilliseconds = "5000" 
operationTimeoutInMilliseconds = "1000"

How do I approach these time-outs? Would increasing operationTimeoutInMilliseconds do the trick? I also read about g-zip compression being helpful for decreasing time that it takes to read the data from Redis.

All nuget packages related to Redis are on their latest versions. We are using C1 version of Azure Redis Cache (would increasing to C2 help?).

回答1:

A few points that improved our situation:

Protobuf-net instead of BinaryFormatter

I recommend using protobuf-net as it will reduce the size of values that you want to store in your cache.

public interface ICacheDataSerializer
    {
        byte[] Serialize(object o);
        T Deserialize<T>(byte[] stream);
    }

public class ProtobufNetSerializer : ICacheDataSerializer
    {
        public byte[] Serialize(object o)
        {
            using (var memoryStream = new MemoryStream())
            {
                Serializer.Serialize(memoryStream, o);

                return memoryStream.ToArray();
            }
        }

        public T Deserialize<T>(byte[] stream)
        {
            var memoryStream = new MemoryStream(stream);

            return Serializer.Deserialize<T>(memoryStream);
        }
    }

Implement retry strategy

Implement this RedisCacheTransientErrorDetectionStrategy to handle timeout issues.

using Microsoft.Practices.TransientFaultHandling;

public class RedisCacheTransientErrorDetectionStrategy : ITransientErrorDetectionStrategy
    {
        /// <summary>
        /// Custom Redis Transient Error Detenction Strategy must have been implemented to satisfy Redis exceptions.
        /// </summary>
        /// <param name="ex"></param>
        /// <returns></returns>
        public bool IsTransient(Exception ex)
        {
            if (ex == null) return false;

            if (ex is TimeoutException) return true;

            if (ex is RedisServerException) return true;

            if (ex is RedisException) return true;

            if (ex.InnerException != null)
            {
                return IsTransient(ex.InnerException);
            }

            return false;
        }
    }

Instantiate like this:

private readonly RetryPolicy _retryPolicy;

// CODE
var retryStrategy = new FixedInterval(3, TimeSpan.FromSeconds(2));
            _retryPolicy = new RetryPolicy<RedisCacheTransientErrorDetectionStrategy>(retryStrategy);

Use like this:

var cachedString = _retryPolicy.ExecuteAction(() => dataCache.StringGet(fullCacheKey));

Review your code to minimize cache calls and values that you are storing in your cache. I reduced lots of errors by storing values more efficiently.

If none of this helps. Move to higher cache (we ended up using C3 instead of C1).

回答2:

In all of your exception messages, you have something like "in=65536/0". This indicates that 65536 bytes have been received locally (in the kernel's socket buffer on the local machine) but have not yet been processed by StackExchange.Redis. This would point at an issue on the client app side of things that is keeping the system from processing your response. Two possibilities I can think of that could lead to this:

Your system does not have enough free thread pool threads to process the data fast enough. If you update to build 1.0.450 or later of StackExchange.Redis, the timeout messages will include statistics for how busy the thread pool is, which will help diagnose this issue. Alternatively, you can take use code like https://github.com/JonCole/SampleCode/blob/master/ThreadPoolMonitor/ThreadPoolLogger.cs to log this same information yourself whenever you get an exception.
You are receiving a very large object from the cache and the size of the object is not received within the timeout configured on StackExchange.Redis. When this happens, all calls that were queued onto the same connection behind the large item will timeout when the large item times out.

Anyway, hope this helps.