Re: How squid caches some things

From: Evgeny Kotsuba <evgen__k@dont-contact.us>
Date: Tue, 11 Oct 2005 23:54:06 +0400

On Tue, 11 Oct 2005 00:51:07 +0200 (CEST)
  Henrik Nordstrom <hno@squid-cache.org> wrote:
> On Tue, 11 Oct 2005, Evgeny Kotsuba wrote:
>
>> 1128979352.320 470 127.0.0.1 TCP_REFRESH_HIT/200 341 GET
>> http://u1386.48.spylog.com/cnt?p=1 evg NONE/- text/html [Host:
>> u1386.48.spylog.com\r\nUser-Agent: Mozilla/5.0 (OS/2; U; Warp 4.5;
>>en-US;
>> rv:1.4.1) Gecko/20031121\r\nAccept:
>> video/x-mng,image/png,image/jpeg,image/gif;q=0.2,*/*;q=0.1\r\nAccept-Language:
>> ru,en-us;q=0.7,en;q=0.3\r\nAccept-Encoding:
>>gzip,deflate\r\nAccept-Charset:
>> KOI8-R,utf-8;q=0.7,*;q=0.7\r\nKeep-Alive: 300\r\nProxy-Connection:
>> keep-alive\r\nReferer:
>> http://kubok.yandex.ru/regkubok_msk1/a18820af44d1c98777244f3e2da43ebb/?&1029.27724170637\r\nCookie:
>> VISID=DQKCCBIWMIICOCZWTB\r\nProxy-Authorization: Basic
>> ZXZnOjEyMw==\r\nPragma: no-cache\r\n] [HTTP/1.1 200 OK\r\nDate: Sun,
>>09 Oct
>> 2005 12:12:13 GMT\r\nServer: Apache/1.3.6 (OS/2)
>> rus/PL28.16\r\nLast-Modified: Wed, 11 Apr 2001 11:22:00 GMT\r\nETag:
>> "10001a-2b-3ad43e58"\r\nAccept-Ranges: bytes\r\nContent-Length:
>> 43\r\nKeep-Alive: timeout=15, max=100\r\nConnection:
>> Keep-Alive\r\nContent-Type: image/gif\r\n\r]
>
>Forced reload of the cache due to "Pragma: no-cache" request header.
>

Once again.
This url is _REDIRECTED_ to dot.gif at my local apache
  _______^^^^^^^^^^^^^^^^^______________
Why quid ask anything about it ? As well why squid ask DNS about
 it ?

>> ---------------8<--------------------------------
>> (3)
>> 1128979353.680 1700 127.0.0.1 TCP_REFRESH_HIT/200 5269 GET
>> http://kubok.yandex.ru/i/top6.gif evg DIRECT/213.180.204.2 image/gif
>>[Host:
>> kubok.yandex.ru\r\nUser-Agent: Mozilla/5.0 (OS/2; U; Warp 4.5;
>>en-US;
>> rv:1.4.1) Gecko/20031121\r\nAccept:
>> video/x-mng,image/png,image/jpeg,image/gif;q=0.2,*/*;q=0.1\r\nAccept-Language:
>> ru,en-us;q=0.7,en;q=0.3\r\nAccept-Encoding:
>>gzip,deflate\r\nAccept-Charset:
>> KOI8-R,utf-8;q=0.7,*;q=0.7\r\nKeep-Alive: 300\r\nProxy-Connection:
>> keep-alive\r\nReferer:
>> http://kubok.yandex.ru/regkubok_msk1/a18820af44d1c98777244f3e2da43ebb/?&1029.27724170637\r\nCookie:
>> mail_tag=yandex.ru; yandexuid=880632171062857853;
>> yandex_login=\r\nProxy-Authorization: Basic ZXZnOjEyMw==\r\nPragma:
>> no-cache\r\n] [HTTP/1.1 200 OK\r\nDate: Sun, 09 Oct 2005 09:16:56
>> GMT\r\nServer: Apache/1.3.33 (Unix) mod_perl/1.29 PHP/4.4.0
>> rus/PL30.20\r\nLast-Modified: Tue, 04 Oct 2005 16:59:41 GMT\r\nETag:
>> "14da60-134e-4342b4fd"\r\nAccept-Ranges: bytes\r\nContent-Length:
>> 4942\r\nConnection: close\r\nContent-Type: image/gif\r\n\r]
>> ---------------8<--------------------------------
>> Pragma: no-cache
>> Last-Modified: Tue, 04 Oct 2005 16:59:41 GMT
>>
>> Why I should not place this image to cache ?!
>
> It is cached, but the client forbids use of the cached entry (via
>"Pragma: no-cache") forcing the cache to verify freshness.
>
>> It truth somewere near the refresh_pattern ?
>
> You can fiddle with refresh_pattern to override this specific case.
>But beware that overriding "Pragma: no-cache" violates the HTTP
>specifications.

I look at refresh_pattern, but can't see how it is possible to make
simple obvious thing: ignore reload if there is the same object in
cache with the same Last-Modified time

SY,
Evgeny Kotsuba
Received on Tue Oct 11 2005 - 13:54:08 MDT

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