[squid-users] How long this object should be left in the cache?

[Amos Jeffries]

On 03/07/17 20:09, Eliezer Croitoru wrote:
> I had to tune up couple things and I have a question about a HEAD request I
> have seen since something doesn't make sense in them.
> I have the following line in the access log:
> 1499068883.928    163 192.168.168.102 TCP_MISS/200 522 HEAD
> http://download.windowsupdate.com/d/msdownload/update/software/updt/2016/03/
> windows6.1-kb3147071-x64_18992bd5fa0424684c4872e1c10f5663b6d3aa52.psf -
> HIER_DIRECT/8.253.70.46 application/octet-stream Q-CC: "-" "-" Q-P: "-" "-"
> REP-CC: "public,max-age=172800" REP-EXP: "Sat, 05 Nov 2016 03:50:11 GMT"
> VARY: "-" 52:54:00:bc:e3:78 CacheHeader: "MISS from localhost.localdomain"
> 
> And I am using this logformat to get it:
> logformat cache_headers %ts.%03tu %6tr %>a %Ss/%03>Hs %<st %rm %ru %[un
> %Sh/%<a %mt Q-CC: "%{Cache-Control}>h" "%{Cache-Control}>ha" Q-P:
> "%{Pragma}>h" "%{Pragma}>ha" REP-CC: "%{Cache-Control}<h" REP-EXP:
> "%{Expires}<h" VARY: "%{Vary}<h" %>eui CacheHeader: "%{X-Cache}<h"
> access_log daemon:/var/log/squid/access.log cache_headers
> 
> I am not sure if I am seeing right or wrong and if these are real, what is
> expected or how it should be treated since:
> - the expires header is I the past....
> - and against to this it's a public object with a very long maximum age.
> 
> How should squid handle this request what is expected from squid in this
> confusing situation?

It is a HEAD request for something not in cache. What might not be "real"?

IIRC Squid lacks the ability to cache the reply unless there is an 
existing object to update the headers for. So it should just relay the 
messages instead.

Amos