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From Mateusz Zajakala <zajak...@gmail.com>
Subject Re: partial object caching
Date Thu, 06 Aug 2015 19:17:47 GMT
One question about the background fetch plugin. How does it relate (if at
all) to configs
proxy.config.http.background_fill_completed_threshold
proxy.config.http.background_fill_active_timeout

If I understand correctly these configs instruct ATS to continue fetching
file from origin even though the client may disconnect. I also understand
that background fetch plugin does a similar thing when client issues a
byte-range request.

The interesting thing is that when byte-range request comes from the client
ATS reports in logs:
ERR_CLIENT_ABORT/206

So - is background_fill going to kick in? Or do I need the background fetch
plugin?

Ps. The case is delivery (streaming / progressive download) of large (>1GB)
video files with clients issueing range requests.


On Thu, Aug 6, 2015 at 6:00 PM, Madhava Gaikwad (madgaikw) <
madgaikw@cisco.com> wrote:

> This is a problem even with varnish. Let me assess where I can quickly fix
> this. We need one level of indirection(cache) to store the hashes of RR of
> same URLs and then need a correct coalesce operator.
>
>
>
> Thanks for the confirmation and help. Let me get back to you with my
> findings.
>
>
>
> Madhava
>
>
>
> *From:* Rushford, John [mailto:John_Rushford@cable.comcast.com]
> *Sent:* Thursday, August 06, 2015 9:15 PM
>
> *To:* users@trafficserver.apache.org
> *Subject:* Re: partial object caching
>
>
>
> Yes, the requests may be served from cache only if the requested range was
> previously requested.  If you find that all clients are requesting the same
> ranges, the plugin would be of help.
>
>
>
> *Thanks*
>
> --
>
> John J. Rushford
>
> IPCDN Engineering
>
> 1400 Wewatta Street, Denver Colorado 80202
>
> John_Rushford@cable.comcast.com
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> *From: *"Madhava Gaikwad (madgaikw)" <madgaikw@cisco.com>
> *Reply-To: *"users@trafficserver.apache.org" <
> users@trafficserver.apache.org>
> *Date: *Thursday, August 6, 2015 at 9:35 AM
> *To: *"users@trafficserver.apache.org" <users@trafficserver.apache.org>
> *Subject: *RE: partial object caching
>
>
>
> Thanks for the response John. This really looks promising and it meets my
> first requirement. Yes, I wanted to talk about that too. If first client
> send RR for 1-10 bytes and another RR for 11-20 bytes. If second client
> comes and asks for 1-12 bytes, this will still cause a fresh fetch request,
> and cannot be served from cache.
>
>
>
> Thank you.
>
> Madhava
>
>
>
> *From:* Rushford, John [mailto:John_Rushford@cable.comcast.com
> <John_Rushford@cable.comcast.com>]
> *Sent:* Thursday, August 06, 2015 8:41 PM
> *To:* users@trafficserver.apache.org
> *Subject:* Re: partial object caching
>
>
>
> Madhava,
>
>
>
> I recently submitted a range request plugin for ATS.  If your analysis
> shows that clients are deterministic with range requests, my plugin may be
> of use to you.  See plugins/experimental/cache_*range_*requests/
>
>
>
> *Thanks*
>
> --
>
> John J. Rushford
>
> IPCDN Engineering
>
> 1400 Wewatta Street, Denver Colorado 80202
>
> John_Rushford@cable.comcast.com
>
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> *From: *"Madhava Gaikwad (madgaikw)" <madgaikw@cisco.com>
> *Reply-To: *"users@trafficserver.apache.org" <
> users@trafficserver.apache.org>
> *Date: *Thursday, August 6, 2015 at 1:29 AM
> *To: *"users@trafficserver.apache.org" <users@trafficserver.apache.org>
> *Subject: *partial object caching
>
>
>
> Hello experts,
>
>
>
> I have legacy forward proxy used in enterprise network facing to internet
> behind firewall. Unfortunately it cannot do partial object caching. I am
> looking if I can get an alternate proxy to do this.
>
> My requirement is:
>
> 1.       Partial object caching so updates by apple etc. can be cached.
> Also video caching will just work.
>
> 2.       Streaming to multiple client at same time should be possible
> from single server connection.
>
>
>
> It seems varnish can do above stuff. But it works effectively as reverse
> proxy, so I have to position it before my proxy, as it cannot work as
> upstream proxy directly. Also its cache seems gets vanished after
> restart(Everything in cache is from heap).
>
> Do you guys know if ATS can do this functionality? I believe it is not
> possible, but I thought just ask if we achieve this by any means. A
> pointing to how to would be really appreciated.
>
>
>
>
>
> Thank you from Newbie,
>
> Madhava
>

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