[squid-users] Lots of "Vary object loop!"

[Sebastián Goicochea]

Amos, thanks for your answer. I understand your point in 
collapsed_forwarding not being triggered because the requests are not 
concurrent, nevertheless if I use collapsed_forwarding the Vary loop 
appears, if I disable it, format the cache_dir and start over .. It does 
not appear.

If you think I could do something else to debug this I'll be glad to do 
it. For now I've disabled collapsed_forwarding in my production servers 
and everything looks good


Regards,
Sebastian

El 15/09/15 a las 07:37, Amos Jeffries escribió:
> On 15/09/2015 9:16 a.m., Sebastián Goicochea wrote:
>> I could finally isolate the problem, it only happens if you are using
>> collapsed_forwarding.
>>
>> If you want, you can use this script to replicate it:
>>
>> #!/bin/bash
>> H='--header'
>>
>> echo "With Firefox"
>> wget -d  \
>> $H='Accept:
>> text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8' \
>> $H='Accept-Encoding: gzip, deflate' \
>> $H='Accept-Language: en-us,en;q=0.5' \
>> $H='Cache-Control: max-age=0' \
>> $H='Connection: keep-alive' \
>> -U 'Mozilla/5.0 (Windows NT 5.1; rv:10.0.2) Gecko/20100101
>> Firefox/10.0.2' \
>> -O /dev/null \
>>   $1
>>
>> echo "With Chrome"
>> wget -d  \
>> $H='Accept:text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8'\
>>
>> $H='Accept-Charset:ISO-8859-1,utf-8;q=0.7,*;q=0.3'\
>> $H='Accept-Encoding:gzip,deflate,sdch'\
>> $H='Accept-Language:es-ES,es;q=0.8'\
>> $H='Cache-Control:no-cache'\
>> $H='Connection:keep-alive'\
>> $H='Pragma:no-cache'\
>> -U 'User-Agent:Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.32
>> (KHTML, like Gecko) Chrome/27.0.1425.0 Safari/537.32 SUSE/27.0.1425.0'\
>> -O /dev/null \
>>   $1
>> # End of script
>>
>> script usage: ./wgets.sh
>> http://www.clarin.com/external-images/GranDTUnificada_5729dd7a1487678526c23516a5083661.jpg
>>
> That script is not doing what you think it is.
>
> The requests are being made in series with the first one finishing
> before the second starts. Your access.log timing confirms that with a
> whole 18ms between the two requests.
>
> So I dont think this script is actually triggering the collapsed
> forwarding behaviour. Or it should not be if it is.
>
>
> Also, look closely for the "\r\n" between headers.
>
> [User-Agent: Wget/1.12
>> (linux-gnu)\r\nAccept:
>> text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8--header=Accept-Charset:ISO-8859-1,utf-8;q=0.7,*;q=0.3--header=Accept-Encoding:gzip,deflate,sdch--header=Accept-Language:es-ES,es;q=0.8--header=Cache-Control:no-cache--header=Connection:keep-alive--header=Pragma:no-cache-U\r\nHost:
>> www.clarin.com\r\nConnection: Keep-Alive\r\n]
>> cache.log output:
>> 2015/09/14 14:05:01 kid1| clientProcessHit: Vary object loop!
>> 2015/09/14 14:05:27 kid1| varyEvaluateMatch: Oops. Not a Vary match on
>> second attempt,
>> 'http://www.clarin.com/external-images/GranDTUnificada_5729dd7a1487678526c23516a5083661.jpg'
>> 'accept-encoding="gzip,%20deflate",
>> user-agent="Mozilla%2F5.0%20(Windows%20NT%205.1%3B%20rv%3A10.0.2)%20Gecko%2F20100101%20Firefox%2F10.0.2"'
>>
>> 2015/09/14 14:05:27 kid1| clientProcessHit: Vary object loop!
>> 2015/09/14 14:05:27 kid1| varyEvaluateMatch: Oops. Not a Vary match on
>> second attempt,
>> 'http://www.clarin.com/external-images/GranDTUnificada_5729dd7a1487678526c23516a5083661.jpg'
>> 'accept-encoding, user-agent="Wget%2F1.12%20(linux-gnu)"'
>> 2015/09/14 14:05:27 kid1| clientProcessHit: Vary object loop!
>>
>> What do you think? Is this the expected behaviour?
>>
> There is something slightly odd. I'm not sure if its wrong exactly, but
> definitely odd.
>
>
> Its not clear if the cache.log output is from the first or second
> request. I assume (big IF) that above cache.log is the first one finding
> some prior Firefox entry, then the second one finding the first ones entry.
>
> Its very weird that the second one gets "Not a Vary match". The lookups
> should have been the same regardless of your script breakage.
>
> Amos
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