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Posted to users@trafficserver.apache.org by Esmq <es...@163.com> on 2013/06/27 04:27:29 UTC
ts may return incorrect Age header?
hi,all
i observed that ts sometimes return with Age header which value greater than 0, (but the value never greater than 5 or so)
but i when looking for access log, all is TCP_MISS...
TCP_MISS and the Age header value greater that 0....isn't that conflict?!
Re: ts may return incorrect Age header?
Posted by James Peach <jp...@apache.org>.
On Jun 26, 2013, at 7:45 PM, Jan van Doorn <jv...@knutsel.com> wrote:
> Hmmm...
>
> How can you see from the client's persepctive if this was a hit or miss? I've been using the Age: header, but have been confused by this same problem. I know I can setproxy.config.http.insert_response_via_str to 3, but what if I don't want to expose that much information in all responses?
Would https://issues.apache.org/jira/browse/TS-1571 help?
>
>
> Rgds,
> JvD
>
> On 06/26/2013 08:35 PM, Leif Hedstrom wrote:
>> On 6/26/13 8:27 PM, Esmq wrote:
>>> hi,all
>>>
>>> i observed that ts sometimes return with Age header which value greater than 0, (but the value never greater than 5 or so)
>>>
>>> but i when looking for access log, all is TCP_MISS...
>>>
>>> TCP_MISS and the Age header value greater that 0....isn't that conflict?!
>>
>>
>> Typically means that your origin took > 0s and (in your case) less than 5s to respond. Age: starts when ATS sends the request to origin.
>>
>> -- Leif
>
>
Re:Re: ts may return incorrect Age header?
Posted by Esmq <es...@163.com>.
Very Good Explanation
thanks all
At 2013-06-27 10:59:51,"Leif Hedstrom" <zw...@apache.org> wrote:
>On 6/26/13 8:45 PM, Jan van Doorn wrote:
>> Hmmm...
>>
>> How can you see from the client's persepctive if this was a hit or miss?
>> I've been using the Age: header, but have been confused by this same
>> problem. I know I can set proxy.config.http.insert_response_via_str to 3,
>> but what if I don't want to expose that much information in all responses?
>
>curl -s -D - -o /dev/null -H "Cache-Control: only-if-cached"
>http://www.example.com/some/url.html
>
>
>or, the Via headers, or the logs. Typically though, if you origin takes that
>long that you can't distinguish between a probably cache hit, and a cache
>miss, something is odd ;). Age: is never certain to specify if it's a cahce
>hit or not, it's not the semantics of it at all.
>
>Cheers,
>
>-- Leif
>
Re: ts may return incorrect Age header?
Posted by Leif Hedstrom <zw...@apache.org>.
On 6/26/13 8:45 PM, Jan van Doorn wrote:
> Hmmm...
>
> How can you see from the client's persepctive if this was a hit or miss?
> I've been using the Age: header, but have been confused by this same
> problem. I know I can set proxy.config.http.insert_response_via_str to 3,
> but what if I don't want to expose that much information in all responses?
curl -s -D - -o /dev/null -H "Cache-Control: only-if-cached"
http://www.example.com/some/url.html
or, the Via headers, or the logs. Typically though, if you origin takes that
long that you can't distinguish between a probably cache hit, and a cache
miss, something is odd ;). Age: is never certain to specify if it's a cahce
hit or not, it's not the semantics of it at all.
Cheers,
-- Leif
Re: ts may return incorrect Age header?
Posted by Jan van Doorn <jv...@knutsel.com>.
Hmmm...
How can you see from the client's persepctive if this was a hit or miss?
I've been using the Age: header, but have been confused by this same
problem. I know I can set proxy.config.http.insert_response_via_str to
3, but what if I don't want to expose that much information in all
responses?
Rgds,
JvD
On 06/26/2013 08:35 PM, Leif Hedstrom wrote:
> On 6/26/13 8:27 PM, Esmq wrote:
>> hi,all
>>
>> i observed that ts sometimes return with Age header which value
>> greater than 0, (but the value never greater than 5 or so)
>>
>> but i when looking for access log, all is TCP_MISS...
>>
>> TCP_MISS and the Age header value greater that 0....isn't that
>> conflict?!
>
>
> Typically means that your origin took > 0s and (in your case) less
> than 5s to respond. Age: starts when ATS sends the request to origin.
>
> -- Leif
Re: ts may return incorrect Age header?
Posted by Leif Hedstrom <zw...@apache.org>.
On 6/26/13 8:27 PM, Esmq wrote:
> hi,all
>
> i observed that ts sometimes return with Age header which value greater
> than 0, (but the value never greater than 5 or so)
>
> but i when looking for access log, all is TCP_MISS...
>
> TCP_MISS and the Age header value greater that 0....isn't that conflict?!
Typically means that your origin took > 0s and (in your case) less than 5s
to respond. Age: starts when ATS sends the request to origin.
-- Leif