[squid-users] Squid logs TCP_MISS/200 for a served cached object requested with If-None-Match

[Garri Djavadyan]

On 2016-11-28 17:39, Garri Djavadyan wrote:
> On Sat, 2016-11-19 at 01:12 +0500, Garri Djavadyan wrote:
>> Hello,
>> 
>> I noticed that Squid logs TCP_MISS/200 when it serves previously
>> cached 
>> object in return to non-matched conditional request with If-None-
>> Match. 
>> For example:
>> 
>> 1. Non-conditional request to the previously cached object.
>> 
>> $ curl -v -x http://127.0.0.1:3128 
>> http://mirror.comnet.uz/centos/7/os/x86_64/GPL >/dev/null
>> 
>> < HTTP/1.1 200 OK
>> < Server: nginx
>> < Date: Fri, 18 Nov 2016 19:58:38 GMT
>> < Content-Type: application/octet-stream
>> < Content-Length: 18009
>> < Last-Modified: Wed, 09 Dec 2015 22:35:46 GMT
>> < ETag: "5668acc2-4659"
>> < Accept-Ranges: bytes
>> < Age: 383
>> < X-Cache: HIT from gentoo.comnet.uz
>> < Via: 1.1 gentoo.comnet.uz (squid/5.0.0-BZR)
>> < Connection: keep-alive
>> 
>> 
>> 2. Conditional request with non-matching entity to the same object.
>> 
>> $ curl -v -x http://127.0.0.1:3128 -H 'If-None-Match: "5668acc2-
>> 4658"' 
>> http://mirror.comnet.uz/centos/7/os/x86_64/GPL >/dev/null
>> 
>> < HTTP/1.1 200 OK
>> < Server: nginx
>> < Date: Fri, 18 Nov 2016 19:58:38 GMT
>> < Content-Type: application/octet-stream
>> < Content-Length: 18009
>> < Last-Modified: Wed, 09 Dec 2015 22:35:46 GMT
>> < ETag: "5668acc2-4659"
>> < Accept-Ranges: bytes
>> < X-Cache: MISS from gentoo.comnet.uz
>> < Via: 1.1 gentoo.comnet.uz (squid/5.0.0-BZR)
>> < Connection: keep-alive
>> 
>> 
>> I found that the behavior is related to the following code 
>> (client_side_reply.cc):
>> 
>>          if (!e->hasIfNoneMatchEtag(r)) {
>>              // RFC 2616: ignore IMS if If-None-Match did not match
>>              r.flags.ims = false;
>>              r.ims = -1;
>>              r.imslen = 0;
>>              r.header.delById(Http::HdrType::IF_MODIFIED_SINCE);
>> --->        http->logType = LOG_TCP_MISS;
>>              sendMoreData(result);
>>              return true;
>>          }
>> 
>> 
>> So, it seems like intended behavior, but I can't understand the
>> reasons.
>> Or maybe it is a bug?
>> 
>> Thanks.
>> 
>> Garri
> 
> 
> Any comments will be much appreciated. Thanks.
> 
> Garri

I found that the behavior is a blocker for the bug report 4169 [1]

[1] http://bugs.squid-cache.org/show_bug.cgi?id=4169


Garri