AppFabric caching expiring suddenly

Question

I'm currently testing AppFabric caching, but I'm having a strange problem with my caching. Even though I say he needs to cache a simple object for 3 minutes, he only caches it for approximately 3 seconds.

The settings for my cache are as follows:

PS C:> Get-CacheConfig default CacheName : default TimeToLive : 100 mins CacheType : Partitioned Secondaries : 0 IsExpirable : True EvictionType : LRU NotificationsEnabled : False

I built this cache using the following 3 commandlets:

Use-CacheCluster 
Start-CacheCluster
Grant-CacheAllowedClientAccount <myAccount>

Afterwards I try to run the following program (program.cs):

class Program
{
    static void Main(string[] args)
    {
        Console.WriteLine("Press any key to continue, Q to quit");
        while (Console.ReadKey() != new ConsoleKeyInfo('q', ConsoleKey.Q, false, false, false))
        {
            DoStuff();
        }
    }

    static void DoStuff()
    {
        Person p = null;
        DataCacheItem cacheItem = CacheUtility.CurrentCache.GetCacheItem("jebas");
        if (cacheItem != null)
        {
            Console.WriteLine("V - Got my stuff from cache");
            p = (Person)cacheItem.Value;
        }

        if (p == null)
        {
            Console.WriteLine("! - I just did an expensive call");
            p = GetPerson();
            CacheUtility.CurrentCache.Add("jebas", p, new TimeSpan(0, 30, 0));
        }
    }

    private static Person GetPerson()
    {
        return new Person() { FirstName = "Jeroen", LastName = "Van Bastelaere", Id = Guid.NewGuid() };
    }
}

CacheUtility class:

sealed class CacheUtility
{
    private static DataCacheFactory _factory;
    private static DataCache _cache;
    private static readonly object _lock = new object();

    CacheUtility() { }

    public static DataCache CurrentCache
    {
        get
        {
            lock (_lock)
            {
                if (_cache == null)
                {
                    List<DataCacheServerEndpoint> servers = new List<DataCacheServerEndpoint>();
                    servers.Add(new DataCacheServerEndpoint("demo2010a", 22233));
                    DataCacheFactoryConfiguration config = new DataCacheFactoryConfiguration()
                    {
                        Servers = servers
                    };
                    _factory = new DataCacheFactory(config);
                    _cache = _factory.GetDefaultCache();
                }
                return _cache;
            }
        }
    }
}

Using this program, I just run it and press a random key for an amount of time: Most of the time it says "I got it from cache", but once in every 3 seconds it does the expensive call. When I check with Get-CacheStatistics default when he misses the cache he has this:

PS C:> Get-CacheStatistics default

Size : 0 ItemCount : 0 RegionCount : 1 RequestCount : 1543 MissCount : 75

When it is in cache it gives me this:

Size : 566 ItemCount : 1 RegionCount : 1 RequestCount : 1553 MissCount : 77

Using perfmon I was able to tell that my object gets evicted, because the counter Total Evicted Objects rises when I run my program (and it's suddenly not in cache anymore).

I have no idea why it is being evicted though, that's the only object I'm caching at the moment and the server has got plenty of memory left (4GB+)

Can anybody help me to get my object cached for the 30 minutes that I ask it to cache instead of 3 seconds?

Help is very appreciated. :-)

Thanks in advance,

Jeroen

Apparantly resource throttling came into place, I had about 6 w3wp processes, 1 sql and one owstimer process that was taking up a lot of memory (90% of total physical memory) and when the total free memory is below 15% of physical memory it begins to throttle. Killing processes solved the issue for me (or actually: iisreset :-)) — Jeroen Van Bastelaere

BenCr BenCr · Accepted Answer · 2011-11-04T11:01:18

When physical memory becomes low on a Windows Server AppFabric cache host, the cache host can enter a state called throttling. The cache cluster will not write data to any cache that resides on a throttled cache host until the available physical memory increases to resolve the throttled state.

http://msdn.microsoft.com/en-us/library/ff921030.aspx

;)

AppFabric caching expiring suddenly

1 Answers