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• 10-30-2009, 10:41 AM

  JAltrichter Joined on 06-12-2009, 6:36 PM Posts 46

  ARR v2 RC - NETSH HTTP shows extra cache entries for WebResource.axd Reply Contact In examining the HTTP kernel cache on my ARR machines, I have been spotting extra entries for URI's that I would not expect to be cached.  Further, the Cache Entry TTL for these cache entries is very large (> 31500000). Let me provide some background.  Due to issues w/ 3rd party controls when we first tested ARR we engineered our application to segregate cacheable content from data.  So we have one farm that purely caches content (with a 99% cache hit rate) and a second that serves dynamic data without caching. I am seeing HTTP cache entries for resources on the non-cached server farm such as "WebResource.axd"  with these unusual long TTL's.  I am concened that a users might inadvertently received cached data from a different user's session.  However we are not seeing that happen in any of testing.  Can you explain what is going on with these cache entries? At the Server Farm level, my cache setting on the non-cached server farm are as follows:  Memory cache duration = 0  Enable Disk Cache = Off  Enable Request Consolidation = Off  Query String Support  = No Caching Thanks for any replies Jim

  Tags: IIS 7memory cacheARR v2 RC

• 10-30-2009, 1:08 PM

  In reply to

  anilr Joined on 05-23-2006, 6:13 PM Redmond, WA Posts 2,343

  Re: ARR v2 RC - NETSH HTTP shows extra cache entries Reply Contact Setting memory cache duration to 0 only disables caching of static-files that ARR decides to auto-cache even though they do not contain any cache-control headers in the response.  It does not apply to responses which have a Cache-Control/Expires header in the response - what are the headers on the webresource.axd response that is cached? - you can request from wfetch to get that information. (the duration seems like exactly one year). If you want to also disable caching even for responses containing Cache-Control/Expires header, you can add the following to the rule routing the request to that particular web-farm. <serverVariables>   <set name="ARR_CACHE_CONTROL_OVERRIDE" value="1,private" /> </serverVariables> Anil Ruia Senior Software Design Engineer IIS Core Server

• 10-30-2009, 3:30 PM

  In reply to

  JAltrichter Joined on 06-12-2009, 6:36 PM Posts 46

  Re: ARR v2 RC - NETSH HTTP shows extra cache entries Reply Contact Anil, Thanks for the reply.  The reason I specifically asked about Webresource.axd is that is not a user-created content, it is a special handler for retreiving ASP.Net assembly resources (reference http://support.microsoft.com/kb/910442).   For that reason, I would like to understand why the ASP.net resoruce hanlder would be cached on ARR?  Is it by design that this handler conent can be cached?  If truly is a cache-control/expires header issue, where would somone go to change that? I will run down the Cache-Control/Expires header with WFetch 1.4 (http://www.iis.net/downloads/default.aspx?tabid=34&i=1307&g=6) and post back with results. Thanks again, Jim

• 10-30-2009, 3:44 PM

  In reply to

  JAltrichter Joined on 06-12-2009, 6:36 PM Posts 46

  Re: ARR v2 RC - NETSH HTTP shows extra cache entries Reply Contact Anil, I found an instance of Webresource.axd in the HTTP cache then loaded those settings into WFetch and retreived the following cache control headers:  HTTP/1.1 200 OK\r\n Cache-Control: public\r\n Content-Length: 38446\r\n Content-Type: text/javascript\r\n Expires: Sat, 30 Oct 2010 19:22:33 GMT\r\n Last-Modified: Thu, 29 Oct 2009 11:11:31 GMT\r\n Server: Microsoft-IIS/7.0\r\n X-AspNet-Version: 2.0.50727\r\n X-Powered-By: ASP.NET\r\n Date: Fri, 30 Oct 2009 19:36:25 GMT\r\n BTW the "Expires: Sat, 30 Oct 2010 19:22:33 GMT" does look to be a 1 year expiration. Jim

• 10-30-2009, 3:59 PM

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  JAltrichter Joined on 06-12-2009, 6:36 PM Posts 46	Re: ARR v2 RC - NETSH HTTP shows extra cache entries Reply Contact Anil, Just for your reference the each ASP.Net page has the following caching directive.     ' Limit & disable Client Side Cache     Response.Cache.SetCacheability(HttpCacheability.ServerAndNoCache) Jim

• 10-30-2009, 4:17 PM

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  anilr Joined on 05-23-2006, 6:13 PM Redmond, WA Posts 2,343

  Re: ARR v2 RC - NETSH HTTP shows extra cache entries Reply Contact The Cache-Control: public is what makes the content cached forever.  I don't know why asp.net is sending webresource.axd response with Cache-Contro: public (you will have to ask an asp.net expert), but you can use the above server-variable in your rewrite rule to override the cache-control directive being sent by the server. Anil Ruia Senior Software Design Engineer IIS Core Server

• 10-30-2009, 5:19 PM

  In reply to

  JAltrichter Joined on 06-12-2009, 6:36 PM Posts 46

  Re: ARR v2 RC - NETSH HTTP shows extra cache entries Reply Contact Anil, Thanks, we will follow-up on the ASP.Net communities. Preliminary results seem to indicate you can not programmatically control cache headers for WebResource.axd. My riddle to the ARR team is... I only see a HTTP cache entries for WebResource.axd on the ARR servers not on the load balanced content nodes.  Any ideas why that might be different? Jim

• 10-31-2009, 2:08 AM

  In reply to

  anilr Joined on 05-23-2006, 6:13 PM Redmond, WA Posts 2,343	Re: ARR v2 RC - NETSH HTTP shows extra cache entries Reply Contact I know that asp.net in some case will only send cache-control headers for client/proxy caching, but will not ask the content on the server, that is probably why the content in not cached on the backend server. Anil Ruia Senior Software Design Engineer IIS Core Server