[squid-users] Unable to get TCP_MEM_HIT (just TCP_HIT) with rock storage

[duanyao]

在 2017/10/18 上午12:23, Alex Rousskov 写道:
> On 10/16/2017 10:30 PM, duanyao wrote:
>
>> When I test squid with rock storage, I have never got a TCP_MEM_HIT
>> (just TCP_HIT) in access.log.
>>
>> Is this normal, or something is mis-configured?
> Neither :-). You are testing with a Vary-controlled response. The shared
> memory cache does not support caching of Vary-controlled responses yet.
> I failed to find a dedicated feature request for implementing this, but
> the problem has been known for several years [1,2,3].
>
> [1]
> http://bazaar.launchpad.net/~measurement-factory/squid/bag5s/revision/12743
> [2] https://bugs.squid-cache.org/show_bug.cgi?id=3806#c9
> [3]
> https://github.com/squid-cache/squid/commit/b8a899c01051c27f2d46f5b9fcbcd27622f388ff
>

I guess this issue will unlikely be fixed any time soon. So is there any 
workaround? Something in my mind:
1) Configure squid to ignore "Vary: Accept-Encoding" and assume all 
clients can handle any Content-Encoding from original servers (this make 
sense in my use case).
2) Use non-shared memory cache with Rock storage.

>> I do get TCP_MEM_HIT with ufs storage.
> To be more precise, you are getting TCP_MEM_HIT with a non-shared memory
> cache. This is not a Rock problem; it is a shared memory cache problem.
> Switching to UFS appears to help because it disables SMP and shared
> memory caching in your specific Squid configuration.
>
>
> Please note that your cache.log does not contain the lines relevant to
> storing the response in the memory cache so there may be other,
> additional reasons why your test response does not get memory-cached. If
> you continue testing and need to report more details, please start from
> a clean cache and post the log containing the very first (cache miss)
> transaction as well as the subsequent (hit) transactions. Compress the
> logs as needed.
>
>
> Thank you,
>
> Alex.
>
>
>
>> I run squid locally, and run `curl -v -x localhost:3128
>> http://localhost:8001/1000 > /dev/null` two times successively, and
>> expect at least the second one being TCP_MEM_HIT, but it is always TCP_HIT.
>>
>>
>> Attachment "squid.conf" is my configuration file; and "cache.rock.log"
>> is the part of cache.log during 2 successive accesses to a same URL;
>> "anysize-server.js" is the HTTP server at port 8001 for the test, and
>> you can run it by `node anysize-server.js`.
>>
>>
>> I tested squid 3.5.27 and 4.0.21, both compiled and run on Linux x86_64:
>> `./configure --with-default-user=duanyao
>> --prefix=/home/duanyao/project/proxy/squid-root/`.
>>
>>
>> Thanks.
>>
>>
>> Duan, Yao
>>
>>
>>
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