Re: [squid-users] AVG Updates not being cached with squid 2.6?

Richard Chapman wrote:
> Amos Jeffries wrote:
>> Richard Chapman wrote:
>>> I have a more or less default configured squid 2.6 proxy on a centos
>>> 5.4 server.
>>> I have configured AVG 9 network edition (Virus scanner) to use the
>>> squid proxy (as opposed to the avg proxy) - and it appears to be
>>> doing so.
>>> However - checking the usage logs - it appears that different client
>>> machines download identical update (.bin) files within a few hours of
>>> each other - but do not appear to get a cache hit..
>>>
>>> Can anyone suggest why these update files are not being cached (or at
>>> least not getting cache hits) - and whether there is anything I can
>>> do to encourage them to be cached?
>>>
>>> I have checked the Squid FAQ and searched the archive - and found a
>>> similar request from 2005. The suggestion there was that the AVG
>>> server might be using the
>>>
>>> "Pragma: no-cache" HTTP header
>>
>> To be sure take the URL that should be a HIT and enter it at redbot.org.
>> The whole problems should be easily visible there.
>>
>>>
>>> And that at that time there was no suggestion on how to override
>>> this. Can anyone confirm that this is the reason for the apparently
>>> unnecessary cache misses - and if so - is there anything new in squid
>>> to allow us to override?
>>>
>>
>> Squid which do not ignore "Pragma: no-cache" treat it the same as
>> "Cache-Control: no-cache"
>>
>> Amos
> Thanks Amos
> I tried redbot as you suggested - and this is a url which I think SHOULD
> have been a hit - though it is hard to be sure. The stats show that NONE
> of the avg updates come from cache - and I assume they should all have
> similar headers... Hopefully someone more knowledgeable than I can make
> more sense of this;
>
> http://redbot.org/?uri=http://aa.avg.com/softw/90/update/u7iavi2551u2550qp.bin
>
>
>
> It looks to me that it should be cacheable - but the only suspicious
> thing is the statement I get when I hover over the "This response is
> stale". I think it says that it has a "Freshnes lifetime of 0" - which
> sounds like it will always be considered stale. I'm not sure why they
> would do this as each update has a unique file name - and could
> therefore be considered fresh indefinitely couldn't it?
>
> Can anyone confirm my interpretation - and/or suggest a way to treat the
> updates more rationally?
>
> Richard.
>
>
>
> A cache considers a HTTP response stale when its age (here, 0) is equal
> to or exceeds its freshness lifetime (in this case, 0)
>
> A A cache considers a HTTP response stale when its age (here, 0) is
> equal to or exceeds its freshness lifetime (in this case, 0).cache
> considers a HTTP response stale when its age (here, 0) is equal to or
> exceeds its freshness lifetime (in this case, 0).

Hmm, something strange there.

AFAIK the object looks like with the L-M header + the Date should have
both non-zero freshness (Date - LM) and an age (now - Date).

Amos

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