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Posted to users@trafficserver.apache.org by Veiko Kukk <ve...@gmail.com> on 2017/11/23 14:35:46 UTC
Avoiding TCP_REFRESH_HIT
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
Re: Avoiding TCP_REFRESH_HIT
Posted by Veiko Kukk <ve...@gmail.com>.
Just to give back to community what was the final solution
* /etc/trafficserver/header_rewrite.config [1]
cond %{READ_RESPONSE_HDR_HOOK} [AND]
cond %{STATUS} = 200
rm-header Expires
set-header Cache-Control "max-age=157784630"
* /etc/trafficserver/plugin.config [2]
header_rewrite.so header_rewrite.config
* /etc/trafficserver/records.config [3]
CONFIG proxy.config.http.cache.required_headers INT 2
[1]
https://docs.trafficserver.apache.org/en/7.1.x/admin-guide/plugins/header_rewrite.en.html
[2]
https://docs.trafficserver.apache.org/en/7.1.x/admin-guide/files/plugin.config.en.html
[3]
https://docs.trafficserver.apache.org/en/7.1.x/admin-guide/files/records.config.en.html#proxy-config-http-cache-required-headers
It's important to add max-age only to HTTP status code 200 and to set
required headers to contain max-age.
set-header overwrites existing 'Cache-Control'.
Regards,
Veiko
2017-11-24 11:24 GMT+02:00 Veiko Kukk <ve...@gmail.com>:
> Hi,
>
> 1) I don't know. ATS is not in production yet, i just noticed that it
> happened during testing. Since we are just moving from Squid to ATS, i'm
> testing latest stable ATS, thats being 7.1.1 at the moment.
>
> 2) Thank you for that! That's exatly what I was looking for, some clever
> way to overwrite ATS staleness decision.
>
> Regards,
> Veiko
>
>
> 2017-11-23 22:33 GMT+02:00 Shu Kit Chan <ch...@gmail.com>:
>
>> 1) How often does TCP_REFRESH_HIT happen? Just a wild guess. If you
>> are using ATS < 6.2.0, there is a fuzz feature that may cause this to
>> happen very once in a while.
>>
>> 2) Here is an alternative approach. you can try to use ts_lua plugin
>> with the following script.
>>
>> function cache_lookup()
>> ts.debug('cache-lookup')
>> -- mark stale hit as fresh hit
>> local cache_status = ts.http.get_cache_lookup_status()
>> if cache_status == TS_LUA_CACHE_LOOKUP_HIT_STALE then
>> ts.debug('stale hit')
>> ts.http.set_cache_lookup_status(TS_LUA_CACHE_LOOKUP_HIT_FRESH)
>> end
>> return 0
>> end
>>
>> function do_global_read_request()
>> ts.hook(TS_LUA_HOOK_CACHE_LOOKUP_COMPLETE, cache_lookup)
>> return 0
>> end
>>
>> 3) You can also try to debug it by turning on debug and use debug tag
>> of "http.*" and see what kind of messages are generated in traffic.out
>> when TCP_REFRESH_HIT happened. It should give you some hints on why a
>> revalidate is needed.
>>
>> Thanks. Hopefully it helps.
>>
>> Kit
>>
>>
>>
>> On Thu, Nov 23, 2017 at 10:41 AM, Stephen Washburn
>> <st...@stephenwashburn.com> wrote:
>> > Ah… sorry about that.
>> >
>> > Stephen
>> >
>> > On Nov 23, 2017, at 10:22, Veiko Kukk <ve...@gmail.com> wrote:
>> >
>> > Hi Stephen,
>> >
>> > As i wrote in my first post, i've set CONFIG
>> > proxy.config.http.cache.when_to_revalidate INT 3
>> >
>> > Veiko
>> >
>> >
>> > 2017-11-23 19:56 GMT+02:00 Stephen Washburn <
>> stephen@stephenwashburn.com>:
>> >>
>> >> Apologies if I’m missing something, but doesn’t that page say that
>> there
>> >> is an option to have it treat freshness as such:
>> >>
>> >> Traffic Server considers all HTTP objects in the cache to be
>> fresh:Never
>> >> revalidate HTTP objects in the cache with the origin server.
>> >>
>> >>
>> >> By modifying proxy.config.http.cache.when_to_revalidate
>> >>
>> >>
>> >> https://docs.trafficserver.apache.org/en/7.1.x/admin-guide/
>> files/records.config.en.html#proxy-config-http-cache-when-to-revalidate
>> >>
>> >> Stephen
>> >>
>> >> On Nov 23, 2017, at 09:26, Veiko Kukk <ve...@gmail.com> wrote:
>> >>
>> >> Now to think about it, i might have set dest_domain to wrong value.
>> >> Documentation is not that clear on that. If there are x.y.z.tld and
>> >> a.b.z.tld then what have to be written to dest_domain to capture both
>> of
>> >> those?
>> >> dest_domain=z.tld
>> >> or
>> >> dest_domain=*.*.z.tld
>> >>
>> >> Or someting else?
>> >>
>> >> Veiko
>> >>
>> >>
>> >> 2017-11-23 19:20 GMT+02:00 Veiko Kukk <ve...@gmail.com>:
>> >>>
>> >>> Hi Alan,
>> >>>
>> >>> That is what i had already done in cache.config:
>> >>> dest_domain=.*.source.tld ttl-in-cache=9999d
>> >>>
>> >>> Of cource, source.tld is actually real domain, and this did not avoid
>> >>> checking origin for object freshness, it was still considered stale
>> by ATS.
>> >>>
>> >>>
>> >>> https://docs.trafficserver.apache.org/en/7.1.x/admin-guide/
>> configuration/cache-basics.en.html#ensuring-cached-object-freshness
>> >>> describes that if Expires is present, it is used to calculate objects
>> >>> freshness. And there is no way to ignore it. I've configured now ATS
>> to
>> >>> remove Expires header and set Cache-control: max-age=157784630 with
>> header
>> >>> rewrite plugin and cond %{READ_RESPONSE_HDR_HOOK}
>> >>> Will see it that helps.
>> >>>
>> >>> Veiko
>> >>>
>> >>>
>> >>> 2017-11-23 18:38 GMT+02:00 Alan Carroll <so...@oath.com>:
>> >>>>
>> >>>> You might try fiddling with the 'cache.config' file and set a cache
>> TTL
>> >>>> of 10 years or so.
>> >>>>
>> >>>> On Thu, Nov 23, 2017 at 10:11 AM, Veiko Kukk <ve...@gmail.com>
>> >>>> wrote:
>> >>>>>
>> >>>>> Hi David,
>> >>>>>
>> >>>>> Objects are not fetched from ATS via browser. ATS is just internal
>> >>>>> cache. Only problem is to trick ATS into believing that object is
>> always
>> >>>>> fresh, never stale.
>> >>>>> I wonder if modifying headers before ATS (READ_RESPONSE_HDR_HOOK)
>> >>>>> removing or changing Expires and/or adding max-age to some very big
>> value
>> >>>>> might be right way to go for me.
>> >>>>>
>> >>>>> Veiko
>> >>>>>
>> >>>>>
>> >>>>> 2017-11-23 17:52 GMT+02:00 David Carlin <dc...@oath.com>:
>> >>>>>>
>> >>>>>> 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 <ve...@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
>> >>>>>>>>
>> >>>>>>>
>> >>>>>>
>> >>>>>
>> >>>>
>> >>>
>> >>
>> >
>>
>
>
Re: Avoiding TCP_REFRESH_HIT
Posted by Veiko Kukk <ve...@gmail.com>.
Hi,
1) I don't know. ATS is not in production yet, i just noticed that it
happened during testing. Since we are just moving from Squid to ATS, i'm
testing latest stable ATS, thats being 7.1.1 at the moment.
2) Thank you for that! That's exatly what I was looking for, some clever
way to overwrite ATS staleness decision.
Regards,
Veiko
2017-11-23 22:33 GMT+02:00 Shu Kit Chan <ch...@gmail.com>:
> 1) How often does TCP_REFRESH_HIT happen? Just a wild guess. If you
> are using ATS < 6.2.0, there is a fuzz feature that may cause this to
> happen very once in a while.
>
> 2) Here is an alternative approach. you can try to use ts_lua plugin
> with the following script.
>
> function cache_lookup()
> ts.debug('cache-lookup')
> -- mark stale hit as fresh hit
> local cache_status = ts.http.get_cache_lookup_status()
> if cache_status == TS_LUA_CACHE_LOOKUP_HIT_STALE then
> ts.debug('stale hit')
> ts.http.set_cache_lookup_status(TS_LUA_CACHE_LOOKUP_HIT_FRESH)
> end
> return 0
> end
>
> function do_global_read_request()
> ts.hook(TS_LUA_HOOK_CACHE_LOOKUP_COMPLETE, cache_lookup)
> return 0
> end
>
> 3) You can also try to debug it by turning on debug and use debug tag
> of "http.*" and see what kind of messages are generated in traffic.out
> when TCP_REFRESH_HIT happened. It should give you some hints on why a
> revalidate is needed.
>
> Thanks. Hopefully it helps.
>
> Kit
>
>
>
> On Thu, Nov 23, 2017 at 10:41 AM, Stephen Washburn
> <st...@stephenwashburn.com> wrote:
> > Ah… sorry about that.
> >
> > Stephen
> >
> > On Nov 23, 2017, at 10:22, Veiko Kukk <ve...@gmail.com> wrote:
> >
> > Hi Stephen,
> >
> > As i wrote in my first post, i've set CONFIG
> > proxy.config.http.cache.when_to_revalidate INT 3
> >
> > Veiko
> >
> >
> > 2017-11-23 19:56 GMT+02:00 Stephen Washburn <stephen@stephenwashburn.com
> >:
> >>
> >> Apologies if I’m missing something, but doesn’t that page say that there
> >> is an option to have it treat freshness as such:
> >>
> >> Traffic Server considers all HTTP objects in the cache to be fresh:Never
> >> revalidate HTTP objects in the cache with the origin server.
> >>
> >>
> >> By modifying proxy.config.http.cache.when_to_revalidate
> >>
> >>
> >> https://docs.trafficserver.apache.org/en/7.1.x/admin-
> guide/files/records.config.en.html#proxy-config-http-cache-
> when-to-revalidate
> >>
> >> Stephen
> >>
> >> On Nov 23, 2017, at 09:26, Veiko Kukk <ve...@gmail.com> wrote:
> >>
> >> Now to think about it, i might have set dest_domain to wrong value.
> >> Documentation is not that clear on that. If there are x.y.z.tld and
> >> a.b.z.tld then what have to be written to dest_domain to capture both of
> >> those?
> >> dest_domain=z.tld
> >> or
> >> dest_domain=*.*.z.tld
> >>
> >> Or someting else?
> >>
> >> Veiko
> >>
> >>
> >> 2017-11-23 19:20 GMT+02:00 Veiko Kukk <ve...@gmail.com>:
> >>>
> >>> Hi Alan,
> >>>
> >>> That is what i had already done in cache.config:
> >>> dest_domain=.*.source.tld ttl-in-cache=9999d
> >>>
> >>> Of cource, source.tld is actually real domain, and this did not avoid
> >>> checking origin for object freshness, it was still considered stale by
> ATS.
> >>>
> >>>
> >>> https://docs.trafficserver.apache.org/en/7.1.x/admin-
> guide/configuration/cache-basics.en.html#ensuring-cached-object-freshness
> >>> describes that if Expires is present, it is used to calculate objects
> >>> freshness. And there is no way to ignore it. I've configured now ATS to
> >>> remove Expires header and set Cache-control: max-age=157784630 with
> header
> >>> rewrite plugin and cond %{READ_RESPONSE_HDR_HOOK}
> >>> Will see it that helps.
> >>>
> >>> Veiko
> >>>
> >>>
> >>> 2017-11-23 18:38 GMT+02:00 Alan Carroll <so...@oath.com>:
> >>>>
> >>>> You might try fiddling with the 'cache.config' file and set a cache
> TTL
> >>>> of 10 years or so.
> >>>>
> >>>> On Thu, Nov 23, 2017 at 10:11 AM, Veiko Kukk <ve...@gmail.com>
> >>>> wrote:
> >>>>>
> >>>>> Hi David,
> >>>>>
> >>>>> Objects are not fetched from ATS via browser. ATS is just internal
> >>>>> cache. Only problem is to trick ATS into believing that object is
> always
> >>>>> fresh, never stale.
> >>>>> I wonder if modifying headers before ATS (READ_RESPONSE_HDR_HOOK)
> >>>>> removing or changing Expires and/or adding max-age to some very big
> value
> >>>>> might be right way to go for me.
> >>>>>
> >>>>> Veiko
> >>>>>
> >>>>>
> >>>>> 2017-11-23 17:52 GMT+02:00 David Carlin <dc...@oath.com>:
> >>>>>>
> >>>>>> 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 <ve...@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 <ve...@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
> >>>>>>>>
> >>>>>>>
> >>>>>>
> >>>>>
> >>>>
> >>>
> >>
> >
>
Re: Avoiding TCP_REFRESH_HIT
Posted by Shu Kit Chan <ch...@gmail.com>.
1) How often does TCP_REFRESH_HIT happen? Just a wild guess. If you
are using ATS < 6.2.0, there is a fuzz feature that may cause this to
happen very once in a while.
2) Here is an alternative approach. you can try to use ts_lua plugin
with the following script.
function cache_lookup()
ts.debug('cache-lookup')
-- mark stale hit as fresh hit
local cache_status = ts.http.get_cache_lookup_status()
if cache_status == TS_LUA_CACHE_LOOKUP_HIT_STALE then
ts.debug('stale hit')
ts.http.set_cache_lookup_status(TS_LUA_CACHE_LOOKUP_HIT_FRESH)
end
return 0
end
function do_global_read_request()
ts.hook(TS_LUA_HOOK_CACHE_LOOKUP_COMPLETE, cache_lookup)
return 0
end
3) You can also try to debug it by turning on debug and use debug tag
of "http.*" and see what kind of messages are generated in traffic.out
when TCP_REFRESH_HIT happened. It should give you some hints on why a
revalidate is needed.
Thanks. Hopefully it helps.
Kit
On Thu, Nov 23, 2017 at 10:41 AM, Stephen Washburn
<st...@stephenwashburn.com> wrote:
> Ah… sorry about that.
>
> Stephen
>
> On Nov 23, 2017, at 10:22, Veiko Kukk <ve...@gmail.com> wrote:
>
> Hi Stephen,
>
> As i wrote in my first post, i've set CONFIG
> proxy.config.http.cache.when_to_revalidate INT 3
>
> Veiko
>
>
> 2017-11-23 19:56 GMT+02:00 Stephen Washburn <st...@stephenwashburn.com>:
>>
>> Apologies if I’m missing something, but doesn’t that page say that there
>> is an option to have it treat freshness as such:
>>
>> Traffic Server considers all HTTP objects in the cache to be fresh:Never
>> revalidate HTTP objects in the cache with the origin server.
>>
>>
>> By modifying proxy.config.http.cache.when_to_revalidate
>>
>>
>> https://docs.trafficserver.apache.org/en/7.1.x/admin-guide/files/records.config.en.html#proxy-config-http-cache-when-to-revalidate
>>
>> Stephen
>>
>> On Nov 23, 2017, at 09:26, Veiko Kukk <ve...@gmail.com> wrote:
>>
>> Now to think about it, i might have set dest_domain to wrong value.
>> Documentation is not that clear on that. If there are x.y.z.tld and
>> a.b.z.tld then what have to be written to dest_domain to capture both of
>> those?
>> dest_domain=z.tld
>> or
>> dest_domain=*.*.z.tld
>>
>> Or someting else?
>>
>> Veiko
>>
>>
>> 2017-11-23 19:20 GMT+02:00 Veiko Kukk <ve...@gmail.com>:
>>>
>>> Hi Alan,
>>>
>>> That is what i had already done in cache.config:
>>> dest_domain=.*.source.tld ttl-in-cache=9999d
>>>
>>> Of cource, source.tld is actually real domain, and this did not avoid
>>> checking origin for object freshness, it was still considered stale by ATS.
>>>
>>>
>>> https://docs.trafficserver.apache.org/en/7.1.x/admin-guide/configuration/cache-basics.en.html#ensuring-cached-object-freshness
>>> describes that if Expires is present, it is used to calculate objects
>>> freshness. And there is no way to ignore it. I've configured now ATS to
>>> remove Expires header and set Cache-control: max-age=157784630 with header
>>> rewrite plugin and cond %{READ_RESPONSE_HDR_HOOK}
>>> Will see it that helps.
>>>
>>> Veiko
>>>
>>>
>>> 2017-11-23 18:38 GMT+02:00 Alan Carroll <so...@oath.com>:
>>>>
>>>> You might try fiddling with the 'cache.config' file and set a cache TTL
>>>> of 10 years or so.
>>>>
>>>> On Thu, Nov 23, 2017 at 10:11 AM, Veiko Kukk <ve...@gmail.com>
>>>> wrote:
>>>>>
>>>>> Hi David,
>>>>>
>>>>> Objects are not fetched from ATS via browser. ATS is just internal
>>>>> cache. Only problem is to trick ATS into believing that object is always
>>>>> fresh, never stale.
>>>>> I wonder if modifying headers before ATS (READ_RESPONSE_HDR_HOOK)
>>>>> removing or changing Expires and/or adding max-age to some very big value
>>>>> might be right way to go for me.
>>>>>
>>>>> Veiko
>>>>>
>>>>>
>>>>> 2017-11-23 17:52 GMT+02:00 David Carlin <dc...@oath.com>:
>>>>>>
>>>>>> 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 <ve...@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 <ve...@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
>>>>>>>>
>>>>>>>
>>>>>>
>>>>>
>>>>
>>>
>>
>
Re: Avoiding TCP_REFRESH_HIT
Posted by Stephen Washburn <st...@stephenwashburn.com>.
Ah… sorry about that.
Stephen
> On Nov 23, 2017, at 10:22, Veiko Kukk <ve...@gmail.com> wrote:
>
> Hi Stephen,
>
> As i wrote in my first post, i've set CONFIG proxy.config.http.cache.when_to_revalidate INT 3
>
> Veiko
>
>
> 2017-11-23 19:56 GMT+02:00 Stephen Washburn <st...@stephenwashburn.com>:
>> Apologies if I’m missing something, but doesn’t that page say that there is an option to have it treat freshness as such:
>>
>>> Traffic Server considers all HTTP objects in the cache to be fresh:
>>> Never revalidate HTTP objects in the cache with the origin server.
>>
>> By modifying proxy.config.http.cache.when_to_revalidate
>>
>> https://docs.trafficserver.apache.org/en/7.1.x/admin-guide/files/records.config.en.html#proxy-config-http-cache-when-to-revalidate
>>
>> Stephen
>>
>>> On Nov 23, 2017, at 09:26, Veiko Kukk <ve...@gmail.com> wrote:
>>>
>>> Now to think about it, i might have set dest_domain to wrong value. Documentation is not that clear on that. If there are x.y.z.tld and a.b.z.tld then what have to be written to dest_domain to capture both of those?
>>> dest_domain=z.tld
>>> or
>>> dest_domain=*.*.z.tld
>>>
>>> Or someting else?
>>>
>>> Veiko
>>>
>>>
>>> 2017-11-23 19:20 GMT+02:00 Veiko Kukk <ve...@gmail.com>:
>>>> Hi Alan,
>>>>
>>>> That is what i had already done in cache.config:
>>>> dest_domain=.*.source.tld ttl-in-cache=9999d
>>>>
>>>> Of cource, source.tld is actually real domain, and this did not avoid checking origin for object freshness, it was still considered stale by ATS.
>>>>
>>>> https://docs.trafficserver.apache.org/en/7.1.x/admin-guide/configuration/cache-basics.en.html#ensuring-cached-object-freshness describes that if Expires is present, it is used to calculate objects freshness. And there is no way to ignore it. I've configured now ATS to remove Expires header and set Cache-control: max-age=157784630 with header rewrite plugin and cond %{READ_RESPONSE_HDR_HOOK}
>>>> Will see it that helps.
>>>>
>>>> Veiko
>>>>
>>>>
>>>> 2017-11-23 18:38 GMT+02:00 Alan Carroll <so...@oath.com>:
>>>>> You might try fiddling with the 'cache.config' file and set a cache TTL of 10 years or so.
>>>>>
>>>>>> On Thu, Nov 23, 2017 at 10:11 AM, Veiko Kukk <ve...@gmail.com> wrote:
>>>>>> Hi David,
>>>>>>
>>>>>> Objects are not fetched from ATS via browser. ATS is just internal cache. Only problem is to trick ATS into believing that object is always fresh, never stale.
>>>>>> I wonder if modifying headers before ATS (READ_RESPONSE_HDR_HOOK) removing or changing Expires and/or adding max-age to some very big value might be right way to go for me.
>>>>>>
>>>>>> Veiko
>>>>>>
>>>>>>
>>>>>> 2017-11-23 17:52 GMT+02:00 David Carlin <dc...@oath.com>:
>>>>>>> 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 <ve...@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 <ve...@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
>>>>>>>>>
>>>>>>>>
>>>>>>>
>>>>>>
>>>>>
>>>>
>>>
>
Re: Avoiding TCP_REFRESH_HIT
Posted by Veiko Kukk <ve...@gmail.com>.
Hi Stephen,
As i wrote in my first post, i've set CONFIG
proxy.config.http.cache.when_to_revalidate
INT 3
Veiko
2017-11-23 19:56 GMT+02:00 Stephen Washburn <st...@stephenwashburn.com>:
> Apologies if I’m missing something, but doesn’t that page say that there
> is an option to have it treat freshness as such:
>
> *Traffic Server considers all HTTP objects in the cache to be fresh:*Never
> revalidate HTTP objects in the cache with the origin server.
>
>
> By modifying proxy.config.http.cache.when_to_revalidate
>
> https://docs.trafficserver.apache.org/en/7.1.x/admin-
> guide/files/records.config.en.html#proxy-config-http-cache-
> when-to-revalidate
>
> Stephen
>
> On Nov 23, 2017, at 09:26, Veiko Kukk <ve...@gmail.com> wrote:
>
> Now to think about it, i might have set dest_domain to wrong value.
> Documentation is not that clear on that. If there are x.y.z.tld and
> a.b.z.tld then what have to be written to dest_domain to capture both of
> those?
> dest_domain=z.tld
> or
> dest_domain=*.*.z.tld
>
> Or someting else?
>
> Veiko
>
>
> 2017-11-23 19:20 GMT+02:00 Veiko Kukk <ve...@gmail.com>:
>
>> Hi Alan,
>>
>> That is what i had already done in cache.config:
>> dest_domain=.*.source.tld ttl-in-cache=9999d
>>
>> Of cource, source.tld is actually real domain, and this did not avoid
>> checking origin for object freshness, it was still considered stale by ATS.
>>
>> https://docs.trafficserver.apache.org/en/7.1.x/admin-guide/
>> configuration/cache-basics.en.html#ensuring-cached-object-freshness
>> describes that if Expires is present, it is used to calculate objects
>> freshness. And there is no way to ignore it. I've configured now ATS to
>> remove Expires header and set Cache-control: max-age=157784630 with header
>> rewrite plugin and cond %{READ_RESPONSE_HDR_HOOK}
>> Will see it that helps.
>>
>> Veiko
>>
>>
>> 2017-11-23 18:38 GMT+02:00 Alan Carroll <so...@oath.com>:
>>
>>> You might try fiddling with the 'cache.config' file and set a cache TTL
>>> of 10 years or so.
>>>
>>> On Thu, Nov 23, 2017 at 10:11 AM, Veiko Kukk <ve...@gmail.com>
>>> wrote:
>>>
>>>> Hi David,
>>>>
>>>> Objects are not fetched from ATS via browser. ATS is just internal
>>>> cache. Only problem is to trick ATS into believing that object is always
>>>> fresh, never stale.
>>>> I wonder if modifying headers before ATS (READ_RESPONSE_HDR_HOOK)
>>>> removing or changing Expires and/or adding max-age to some very big value
>>>> might be right way to go for me.
>>>>
>>>> Veiko
>>>>
>>>>
>>>> 2017-11-23 17:52 GMT+02:00 David Carlin <dc...@oath.com>:
>>>>
>>>>> 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 <ve...@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 <ve...@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
>>>>>>>
>>>>>>>
>>>>>>
>>>>>
>>>>
>>>
>>
>
Re: Avoiding TCP_REFRESH_HIT
Posted by Stephen Washburn <st...@stephenwashburn.com>.
Apologies if I’m missing something, but doesn’t that page say that there is an option to have it treat freshness as such:
> Traffic Server considers all HTTP objects in the cache to be fresh:
> Never revalidate HTTP objects in the cache with the origin server.
By modifying proxy.config.http.cache.when_to_revalidate
https://docs.trafficserver.apache.org/en/7.1.x/admin-guide/files/records.config.en.html#proxy-config-http-cache-when-to-revalidate
Stephen
> On Nov 23, 2017, at 09:26, Veiko Kukk <ve...@gmail.com> wrote:
>
> Now to think about it, i might have set dest_domain to wrong value. Documentation is not that clear on that. If there are x.y.z.tld and a.b.z.tld then what have to be written to dest_domain to capture both of those?
> dest_domain=z.tld
> or
> dest_domain=*.*.z.tld
>
> Or someting else?
>
> Veiko
>
>
> 2017-11-23 19:20 GMT+02:00 Veiko Kukk <ve...@gmail.com>:
>> Hi Alan,
>>
>> That is what i had already done in cache.config:
>> dest_domain=.*.source.tld ttl-in-cache=9999d
>>
>> Of cource, source.tld is actually real domain, and this did not avoid checking origin for object freshness, it was still considered stale by ATS.
>>
>> https://docs.trafficserver.apache.org/en/7.1.x/admin-guide/configuration/cache-basics.en.html#ensuring-cached-object-freshness describes that if Expires is present, it is used to calculate objects freshness. And there is no way to ignore it. I've configured now ATS to remove Expires header and set Cache-control: max-age=157784630 with header rewrite plugin and cond %{READ_RESPONSE_HDR_HOOK}
>> Will see it that helps.
>>
>> Veiko
>>
>>
>> 2017-11-23 18:38 GMT+02:00 Alan Carroll <so...@oath.com>:
>>> You might try fiddling with the 'cache.config' file and set a cache TTL of 10 years or so.
>>>
>>>> On Thu, Nov 23, 2017 at 10:11 AM, Veiko Kukk <ve...@gmail.com> wrote:
>>>> Hi David,
>>>>
>>>> Objects are not fetched from ATS via browser. ATS is just internal cache. Only problem is to trick ATS into believing that object is always fresh, never stale.
>>>> I wonder if modifying headers before ATS (READ_RESPONSE_HDR_HOOK) removing or changing Expires and/or adding max-age to some very big value might be right way to go for me.
>>>>
>>>> Veiko
>>>>
>>>>
>>>> 2017-11-23 17:52 GMT+02:00 David Carlin <dc...@oath.com>:
>>>>> 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 <ve...@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 <ve...@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
>>>>>>>
>>>>>>
>>>>>
>>>>
>>>
>>
>
Re: Avoiding TCP_REFRESH_HIT
Posted by David Carlin <dc...@oath.com>.
I have not played with cache.config much, but one setting that may impact
dest_domain value is whether or not proxy.config.url_remap.pristine_host_hdr
is enabled.
David
On Thu, Nov 23, 2017 at 12:26 PM, Veiko Kukk <ve...@gmail.com> wrote:
> Now to think about it, i might have set dest_domain to wrong value.
> Documentation is not that clear on that. If there are x.y.z.tld and
> a.b.z.tld then what have to be written to dest_domain to capture both of
> those?
> dest_domain=z.tld
> or
> dest_domain=*.*.z.tld
>
> Or someting else?
>
> Veiko
>
>
> 2017-11-23 19:20 GMT+02:00 Veiko Kukk <ve...@gmail.com>:
>
>> Hi Alan,
>>
>> That is what i had already done in cache.config:
>> dest_domain=.*.source.tld ttl-in-cache=9999d
>>
>> Of cource, source.tld is actually real domain, and this did not avoid
>> checking origin for object freshness, it was still considered stale by ATS.
>>
>> https://docs.trafficserver.apache.org/en/7.1.x/admin-guide/
>> configuration/cache-basics.en.html#ensuring-cached-object-freshness
>> describes that if Expires is present, it is used to calculate objects
>> freshness. And there is no way to ignore it. I've configured now ATS to
>> remove Expires header and set Cache-control: max-age=157784630 with header
>> rewrite plugin and cond %{READ_RESPONSE_HDR_HOOK}
>> Will see it that helps.
>>
>> Veiko
>>
>>
>> 2017-11-23 18:38 GMT+02:00 Alan Carroll <so...@oath.com>:
>>
>>> You might try fiddling with the 'cache.config' file and set a cache TTL
>>> of 10 years or so.
>>>
>>> On Thu, Nov 23, 2017 at 10:11 AM, Veiko Kukk <ve...@gmail.com>
>>> wrote:
>>>
>>>> Hi David,
>>>>
>>>> Objects are not fetched from ATS via browser. ATS is just internal
>>>> cache. Only problem is to trick ATS into believing that object is always
>>>> fresh, never stale.
>>>> I wonder if modifying headers before ATS (READ_RESPONSE_HDR_HOOK)
>>>> removing or changing Expires and/or adding max-age to some very big value
>>>> might be right way to go for me.
>>>>
>>>> Veiko
>>>>
>>>>
>>>> 2017-11-23 17:52 GMT+02:00 David Carlin <dc...@oath.com>:
>>>>
>>>>> 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 <ve...@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 <ve...@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
>>>>>>>
>>>>>>>
>>>>>>
>>>>>
>>>>
>>>
>>
>
Re: Avoiding TCP_REFRESH_HIT
Posted by Veiko Kukk <ve...@gmail.com>.
Now to think about it, i might have set dest_domain to wrong value.
Documentation is not that clear on that. If there are x.y.z.tld and
a.b.z.tld then what have to be written to dest_domain to capture both of
those?
dest_domain=z.tld
or
dest_domain=*.*.z.tld
Or someting else?
Veiko
2017-11-23 19:20 GMT+02:00 Veiko Kukk <ve...@gmail.com>:
> Hi Alan,
>
> That is what i had already done in cache.config:
> dest_domain=.*.source.tld ttl-in-cache=9999d
>
> Of cource, source.tld is actually real domain, and this did not avoid
> checking origin for object freshness, it was still considered stale by ATS.
>
> https://docs.trafficserver.apache.org/en/7.1.x/admin-
> guide/configuration/cache-basics.en.html#ensuring-cached-object-freshness
> describes that if Expires is present, it is used to calculate objects
> freshness. And there is no way to ignore it. I've configured now ATS to
> remove Expires header and set Cache-control: max-age=157784630 with header
> rewrite plugin and cond %{READ_RESPONSE_HDR_HOOK}
> Will see it that helps.
>
> Veiko
>
>
> 2017-11-23 18:38 GMT+02:00 Alan Carroll <so...@oath.com>:
>
>> You might try fiddling with the 'cache.config' file and set a cache TTL
>> of 10 years or so.
>>
>> On Thu, Nov 23, 2017 at 10:11 AM, Veiko Kukk <ve...@gmail.com>
>> wrote:
>>
>>> Hi David,
>>>
>>> Objects are not fetched from ATS via browser. ATS is just internal
>>> cache. Only problem is to trick ATS into believing that object is always
>>> fresh, never stale.
>>> I wonder if modifying headers before ATS (READ_RESPONSE_HDR_HOOK)
>>> removing or changing Expires and/or adding max-age to some very big value
>>> might be right way to go for me.
>>>
>>> Veiko
>>>
>>>
>>> 2017-11-23 17:52 GMT+02:00 David Carlin <dc...@oath.com>:
>>>
>>>> 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 <ve...@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 <ve...@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
>>>>>>
>>>>>>
>>>>>
>>>>
>>>
>>
>
Re: Avoiding TCP_REFRESH_HIT
Posted by Veiko Kukk <ve...@gmail.com>.
Hi Alan,
That is what i had already done in cache.config:
dest_domain=.*.source.tld ttl-in-cache=9999d
Of cource, source.tld is actually real domain, and this did not avoid
checking origin for object freshness, it was still considered stale by ATS.
https://docs.trafficserver.apache.org/en/7.1.x/admin-guide/configuration/cache-basics.en.html#ensuring-cached-object-freshness
describes that if Expires is present, it is used to calculate objects
freshness. And there is no way to ignore it. I've configured now ATS to
remove Expires header and set Cache-control: max-age=157784630 with header
rewrite plugin and cond %{READ_RESPONSE_HDR_HOOK}
Will see it that helps.
Veiko
2017-11-23 18:38 GMT+02:00 Alan Carroll <so...@oath.com>:
> You might try fiddling with the 'cache.config' file and set a cache TTL of
> 10 years or so.
>
> On Thu, Nov 23, 2017 at 10:11 AM, Veiko Kukk <ve...@gmail.com> wrote:
>
>> Hi David,
>>
>> Objects are not fetched from ATS via browser. ATS is just internal cache.
>> Only problem is to trick ATS into believing that object is always fresh,
>> never stale.
>> I wonder if modifying headers before ATS (READ_RESPONSE_HDR_HOOK)
>> removing or changing Expires and/or adding max-age to some very big value
>> might be right way to go for me.
>>
>> Veiko
>>
>>
>> 2017-11-23 17:52 GMT+02:00 David Carlin <dc...@oath.com>:
>>
>>> 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 <ve...@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 <ve...@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
>>>>>
>>>>>
>>>>
>>>
>>
>
Re: Avoiding TCP_REFRESH_HIT
Posted by Alan Carroll <so...@oath.com>.
You might try fiddling with the 'cache.config' file and set a cache TTL of
10 years or so.
On Thu, Nov 23, 2017 at 10:11 AM, Veiko Kukk <ve...@gmail.com> wrote:
> Hi David,
>
> Objects are not fetched from ATS via browser. ATS is just internal cache.
> Only problem is to trick ATS into believing that object is always fresh,
> never stale.
> I wonder if modifying headers before ATS (READ_RESPONSE_HDR_HOOK) removing
> or changing Expires and/or adding max-age to some very big value might be
> right way to go for me.
>
> Veiko
>
>
> 2017-11-23 17:52 GMT+02:00 David Carlin <dc...@oath.com>:
>
>> 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 <ve...@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 <ve...@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
>>>>
>>>>
>>>
>>
>
Re: Avoiding TCP_REFRESH_HIT
Posted by Veiko Kukk <ve...@gmail.com>.
Hi David,
Objects are not fetched from ATS via browser. ATS is just internal cache.
Only problem is to trick ATS into believing that object is always fresh,
never stale.
I wonder if modifying headers before ATS (READ_RESPONSE_HDR_HOOK) removing
or changing Expires and/or adding max-age to some very big value might be
right way to go for me.
Veiko
2017-11-23 17:52 GMT+02:00 David Carlin <dc...@oath.com>:
> 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 <ve...@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 <ve...@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
>>>
>>>
>>
>
Re: Avoiding TCP_REFRESH_HIT
Posted by David Carlin <dc...@oath.com>.
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 <ve...@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 <ve...@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
>>
>>
>
Re: Avoiding TCP_REFRESH_HIT
Posted by Veiko Kukk <ve...@gmail.com>.
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 <ve...@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
>
>