Volodymyr Kostyrko wrote:
I got one file stuck into my cache for two month despite site having
newer version:
1219244034.580 3 192.168.8.18 TCP_HIT/200 50599 GET
http://www.freebsd.org/ports/auditfile.tbz - NONE/-
application/x-bzip-compressed-tar
> fetch -vvvvv http://www.freebsd.org/ports/auditfile.tbz
scheme: [http]
user: []
password: []
host: [www.freebsd.org]
port: [0]
document: [/ports/auditfile.tbz]
---> www.freebsd.org:80
looking up www.freebsd.org
connecting to www.freebsd.org:80
requesting http://www.freebsd.org/ports/auditfile.tbz
>>> GET /ports/auditfile.tbz HTTP/1.1
>>> Host: www.freebsd.org
>>> User-Agent: fetch libfetch/2.0
>>> Connection: close
>>>
<<< HTTP/1.0 200 OK
<<< Content-Type: application/x-bzip-compressed-tar
<<< Accept-Ranges: bytes
<<< ETag: "-943519291"
<<< Last-Modified: Wed, 04 Jun 2008 14:10:03 GMT
last modified: [2008-06-04 14:10:03]
<<< Content-Length: 50198
content length: [50198]
<<< Date: Wed, 04 Jun 2008 14:25:15 GMT
<<< Server: httpd/1.4.x LaHonda
<<< Age: 16663
<<< X-Cache: HIT from utwig.xim.bz
<<< X-Cache-Lookup: HIT from utwig.xim.bz:3128
<<< Via: 1.0 utwig.xim.bz (squid/3.0.STABLE8)
<<< Proxy-Connection: close
<<<
offset 0, length -1, size -1, clength 50198
local size / mtime: 50198 / 1212588603
remote size / mtime: 50198 / 1212588603
auditfile.tbz 100% of 49 kB 21 MBps
Mmmm. No expiry information, so Squid has to do a best-effort
approach. Let's learn about refresh patterns
(http://www.squid-cache.org/Versions/v3/3.0/cfgman/refresh_pattern.html).
The default for Squid includes...
refresh_pattern . 0 20% 4320
...which would match the request mentioned. So what does this mean? In
the absence of expiry information, Squid should use the age (gathered
from the Last Modified date) to infer how long the object will be
fresh. The first number specifies there should be no lower limit on the
freshness of the object. If the freshness calculation concludes that
the object is only fresh for 30 seconds, so be it. The last number
states that the maximum object freshness is 4320 minutes (3 days). Even
if the freshness calculation states the object could be fresh for
another year, we'll verify freshness every 3 days. The middle number is
where the calculation comes in. The cached object was last modified on
June 4, 2008 at 14:10:03 GMT. As the object gets older, it's assumed
that it is less likely to change (we are predicting the future based on
past performance), so after an hour of no changes, we assume that the
object is not going to change in the next 12 minutes (60 * 20%). After
a day of no changes, we assume the object will not change for around 5
hours. At 15 days of no changes we hit the ceiling on freshness (15 *
20%) and our freshness calculation becomes superfluous.
Obviously the object has changed, so you have a few options:
* Use the PURGE method with squidclient
* force a refresh with your browser (hold down shift or control when you
press the refresh or reload button, use the -r switch with squidclient
or --cache=off for wget. fetch does not appear to have a method of
forcing a refresh.)
* Add a cache deny for this domain
* Wait for the freshness calculation to expire (3 days at the most)
> fetch -vvvvv http://www.freebsd.org/ports/auditfile.tbz
scheme: [http]
user: []
password: []
host: [www.freebsd.org]
port: [0]
document: [/ports/auditfile.tbz]
---> www.freebsd.org:80
looking up www.freebsd.org
connecting to www.freebsd.org:80
requesting http://www.freebsd.org/ports/auditfile.tbz
>>> GET /ports/auditfile.tbz HTTP/1.1
>>> Host: www.freebsd.org
>>> User-Agent: fetch libfetch/2.0
>>> Connection: close
>>>
<<< HTTP/1.1 200 OK
<<< Connection: close
<<< Content-Type: application/x-bzip-compressed-tar
<<< Accept-Ranges: bytes
<<< ETag: "-1888419386"
<<< Last-Modified: Wed, 20 Aug 2008 14:40:01 GMT
last modified: [2008-08-20 14:40:01]
<<< Content-Length: 51141
content length: [51141]
<<< Date: Wed, 20 Aug 2008 14:56:35 GMT
<<< Server: httpd/1.4.x LaHonda
<<<
offset 0, length -1, size -1, clength 51141
remote size / mtime: 51141 / 1219243201
auditfile.tbz 100% of 49 kB 28 kBps
config:
cache_replacement_policy heap LFUDA
memory_replacement_policy heap GDSF
refresh_pattern ^ftp: 1440 20% 1440 refresh-ims
refresh_pattern ^gopher: 1440 0% 1440
refresh_pattern . 0 20% 4320
Chris
