Re: [squid-users] Question about refresh_pattern and TCP_MEM_HIT

On 19/09/2012 9:10 a.m., Eliezer Croitoru wrote:
> On 9/18/2012 6:01 PM, Silamael wrote:
>> refresh_pattern foo.example.org 0 0% 0
>> refresh_pattern . 0 20% 14400
>>
>> Now, if i fetch something from foo.example.org i get a
>> TCP_CLIENT_REFRESH_MISS/200
>> The following request for the same url is shown in the squid.log with
>> TCP_MEM_HIT/200.
>> If i understand this correctly the TCP_MEM_HIT means that squid did not
>> reload the requested url but served the request with the object still in
>> memory, isn't it?
>> If so, I'm wondering why this url is kept in the memory cache. The
>> refresh_pattern above should prevent this case and force squid to reload
>> the asked object every time.
>>
>> So, what's the explanation for this behaviour?
>>
>> Thanks in advance!
> The refresh_pattern is regex which might just not match all your request.
> if you do not want to cache you dont change the refresh_pattern to
> 0... but use the:
> cache deny acl

refresh_pattern is *only* a set of default values to apply in absence of
cache-control and expiry headers from the server for Squid to use to
determine staleness on followup requests.

This is why the default (/cgi-bin/|\?) pattern with all zeros is
recommended for use on dynamic content. It defaults to not caching
*unless* the server provides proper caching headers. In which case it is
safe to cache.

I would say from that description that your requested resource response
contains all the required HTTP/1.1 headers to permit and specify both
cacheing and expiry limitations on the tested URL.

Amos
Received on Wed Sep 19 2012 - 00:12:43 MDT