trafficserver-users mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From David Carlin <dcar...@oath.com>
Subject Re: Avoiding TCP_REFRESH_HIT
Date Thu, 23 Nov 2017 15:52:20 GMT
Have you considered adding "Cache-Control: Immutable" to these objects
which will never require re-validation?  This will prevent the browser from
attempting an If-Modified-Since request.

https://hacks.mozilla.org/2017/01/using-immutable-caching-to-speed-up-the-web/

David

On Thu, Nov 23, 2017 at 10:07 AM, Veiko Kukk <veiko.kukk@gmail.com> wrote:

> In addition to my previous e-mail, headers that are provided by source to
> ATS:
>
> < HTTP/1.1 200 OK
> < Content-Length: 1185954
> < Accept-Ranges: bytes
> < Last-Modified: Mon, 02 Nov 2015 17:56:12 GMT
> < Etag: 92ef40097ba87bdf09efcf7e1cefd32a
> < X-Timestamp: 1446486971.39466
> < Content-Type: application/octet-stream
> < Content-Disposition: attachment; filename="ABIYohNyPrJNjvFsAdgN5wc8D-8Yo4ZO.m4s";
> filename*=UTF-8''ABIYohNyPrJNjvFsAdgN5wc8D-8Yo4ZO.m4s
> < Expires: Thu, 23 Nov 2017 15:27:30 GMT
> < X-Trans-Id: tx3a0af5473d5c41d38195c-005a16e30d
> < X-Openstack-Request-Id: tx3a0af5473d5c41d38195c-005a16e30d
> < Date: Thu, 23 Nov 2017 15:02:37 GMT
> < X-IPLB-Instance: 12631
>
> I assume, Expires header is here to blame and must be overriden in ATS
> config, but how? I don't have control over source, its Openstack Swift
> object storage.
>
> Veiko
>
>
> 2017-11-23 16:35 GMT+02:00 Veiko Kukk <veiko.kukk@gmail.com>:
>
>> Hi,
>>
>> Could ATS in reverse proxy mode be configured such way that it would
>> never try to revalidate from source? It is known that in our case, object
>> never changes (and is never refetched from source) and it is desirable to
>> avoid any source validation. Validation verification adds significant
>> overhead and we need to avoid it. Response to client with TCP_REFRESH_HIT
>> would take 100-200ms instead of 0-10 in case of direct local TCP_HIT.
>>
>> I've configured following:
>> dest_domain=.*.source.tld action=ignore-no-cache
>> dest_domain=.*.source.tld revalidate=9999d
>> dest_domain=.*.source.tld ttl-in-cache=9999d
>>
>> CONFIG proxy.config.http.cache.when_to_revalidate INT 3
>> CONFIG proxy.config.http.cache.required_headers INT 0
>>
>> But i still get TCP_REFRESH_HIT even when 9999 days have not passed
>> (obviously).
>>
>> NB! ATS is used as internal cache and our 'client' never explicitly
>> requests revalidation.
>>
>> Thanks,
>> Veiko
>>
>>
>

Mime
View raw message