Re: [squid-users] Re: Squid Reverse Proxy (accel) always contacting the server

From: Daniele Segato <daniele.segato_at_gmail.com>
Date: Mon, 02 Apr 2012 10:05:58 +0200

On 04/02/2012 03:22 AM, Amos Jeffries wrote:
>> Last-Modified: <date here, should change when the content change>
>> Cache-Control: public, max-age=60
>>
>> 60 = 60 seconds, means: squid please do not bother the server for 60
>> seconds after this reply, even if they ask for "If-Modified-Since"
>
> Small correction: means don't ask again until 60 seconds from
> Last-Modified. If Last-Modified is missing or invalid, 60 seconds from
> Date:.

that's not what I've seen

I returned Last-Modified (very old), Date: "now" and max-age: 60

squid3 is not checking the server again for 1 minute, then when it does
it keep replying without checking the server for another 1 minute and so on.

Is it because I specified Age: 0 and Date now?

>> I also added Age: 0 (i tell squid that I'm providing a fresh content).
>> And Date: with the current date, I think this also tells squid the
>> content is fresh
>> not sure those are needed but probably helps.
>
> Tells when the response was generated, in case of transfer delays. Acts
> as a backup for Last-Modified as above, and a value to synchronise
> Expires: comparisons between proxies and servers despite any clock
> difference problems.

My server return Age:0 and Date: "now" that should do right?

>> On the squid size I configured the refresh_pattern <regex> 0 20% 4320
>>
>> without adding any other option, this was perfectly fine.
>
> refresh_pattern provides default values for max-age / min-age and next
> revalidate time if none are provided by the combination of cache control
> headers discussed above. When Expires: or Cache-Control: are sent
> refresh_pattern value is not used.

In the log it say:
2012/04/02 07:35:47.326| refreshCheck: Matched '/alfresco/service/stream
0 20%% 259200'

are you saying this is ignored?

I tried by setting that rule with 0 %20 0 and I had all TCP_MISS

so apparently the rule "win" against the http headers.

or maybe I misunderstood you :)

thanks again,
Daniele
Received on Mon Apr 02 2012 - 08:01:47 MDT

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