Re: [squid-users] unexplainable MISSes (squid 2.7stable9)

So, the problem boils down to:

why a cashed version of the page with URL X will be invalidated by an
access to the same URL and a different value in one of the headers
listed in the Vary header? The store log consistently logs:

Mon 08 Nov 2010 11:27:50 PM CET RELEASE 200 text/html GET
http://127.0.0.1:3128/VirtualHostBase/http/www.somewebsite.com:80/www/SITE/VirtualHostRoot/
Mon 08 Nov 2010 11:27:50 PM CET SWAPOUT 200 text/html GET
http://127.0.0.1:3128/VirtualHostBase/http/www.somewebsite.com:80/www/SITE/VirtualHostRoot/
Mon 08 Nov 2010 11:27:50 PM CET SWAPOUT 200 x-squid-internal/vary GET
http://127.0.0.1:3128/VirtualHostBase/http/www.somewebsite.com:80/www/SITE/VirtualHostRoot/
Mon 08 Nov 2010 11:27:50 PM CET RELEASE 200 x-squid-internal/vary GET
http://127.0.0.1:3128/VirtualHostBase/http/www.somewebsite.com:80/www/SITE/VirtualHostRoot/

each time I make a request that has one of the headers in vary with a
different value.

On 11/08/2010 06:33 PM, Adrian Dascalu wrote:
> Done some new tests and I found out that caching an URL that has a
> different X-Username header will invalidate the other version of that
> object.
>
> Is this the intended behaviour? I mean, Vary header will just inform
> there is a new version so everything else is discarded? If so, is there
> a method for cacheing multiple versions of the same URL ?
>
> Adrian
>
> On 11/08/2010 02:33 PM, Adrian Dascalu wrote:
>
>> Hi,
>>
>> I'm out of ideeas trying to debug cache misses that I cannot explain. As a last resort I'm sending this problem to the list with the hope that you could come up with some explanation and/or cure for this.
>>
>> the setup is: squid 2.7stable9 on RHEL 5, configured as accel, 12 parents 1 sibling (another squid). Apache in front zope as parents.
>>
>> For the root page I send requests from the same browser. The page is supposed to stay in cache for 1h. I've seen it behaving correctly one time (at squid startup) afterwards if i keep requesting the page a few times I will get a MISS long before the 3600s have passed.
>>
>> I have checked and there is no PURGE for this URL in the mean time. There are some for other URL's deeper in the structure.
>>
>> here's a request:
>>
>> Host www.somewebsite.com
>>
>> User-Agent Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.1.9) Gecko/20100330 Fedora/3.5.9-1.fc11 Firefox/3.5.9Accepttext/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
>>
>> Accept-Language en-us,en;q=0.5
>>
>> Accept-Encoding gzip,deflate
>>
>> Accept-Charset ISO-8859-1,utf-8;q=0.7,*;q=0.7
>>
>> Keep-Alive 300
>>
>> Connection keep-alive
>>
>> Referer http://www.somewebsite.com/
>>
>> Cookie __utma=173508663.4134765344646281700.1250060356.1271487209.1289208944.50; __utmb=173508663.59.10.1289208944; __utmc=173508663; __utmz=173508663.1289208944.50.1.utmcsr=(direct)|utmccn=(direct)|utmcmd=(none)
>>
>> here's a HIT reply:
>>
>> Date Mon, 08 Nov 2010 12:06:29 GMT
>>
>> Server Zope/(Zope 2.9.10-final, python 2.4.3, linux2) ZServer/1.1 Plone/2.5.5
>>
>> Content-Length 10131
>>
>> Content-Language en
>>
>> Content-Encoding gzip
>>
>> Expires Fri, 10 Nov 2000 12:05:48 GMT
>>
>> Vary Accept-Encoding,Accept,If-None-Match,X-Username
>>
>> X-Caching-Rule-Id plone-containers
>>
>> Cache-Control max-age=0, s-maxage=3600
>>
>> Content-Type text/html;charset=utf-8
>>
>> X-Header-Set-Id cache-in-proxy-1-hour
>>
>> Age 40
>>
>> X-Cache HIT from squid1.somewebsite.com
>>
>> X-Cache-Lookup HIT from squid1.somewebsite.com:3128
>>
>> Via 1.0 squid1.somewebsite.com:3128 (squid/2.7.STABLE9)
>>
>> Keep-Alive timeout=8, max=100
>>
>> Connection Keep-Alive
>>
>> Long before the 3600s have passed ,from the same browser, I would get a MISS. The request headers are IDENTICAL and there is no PURGE. What else might invalidate the cached object?
>>
>>
>> Thank you,
>> Adrian
>>
>>
>>
>>
>
Received on Mon Nov 08 2010 - 22:33:22 MST