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RE: Range Requests vs Content Codings

From: <K.Morgan@iaea.org>
Date: Sat, 21 Jun 2014 16:34:59 +0000
To: <zhong.j.yu@gmail.com>, <roland@zinks.de>
CC: <ietf-http-wg@w3.org>, <C.Brunhuber@iaea.org>
Message-ID: <0356EBBE092D394F9291DA01E8D28EC201186DE96A@sem002pd.sg.iaea.org>
On 18 June 2014 18:35, zhong.j.yu@gmail.com wrote:
> On Wed, Jun 18, 2014 at 5:10 AM, Roland Zink <roland@zinks.de> wrote:
>> A slightly different use case is to access the end of the log file without
>> reading the whole log file. When the log file is content-encoded gzip then a
>> client would need to read the whole log file (possible in chunks) just to be
>> able to decompress the last chunk. With the bbcc scheme and the addition
>> that only the range response is content-encoded this is not necessary.
> There is some logistic issues with this use case that makes it
> unrealistic. There is just one log file (accessible from one URI) that
> grows forever. Assuming the growth is very fast (otherwise we won't
> need gzip+range), the file will quickly reach an impractical size.
> ...
> Another difficulty is at the assumption that the file is only appended
> to, and previously written bytes are never altered. ...
> ...
> ... The proponents
> of bbcc need to uncover a lot more benefit of the feature to justify
> its cost.

I basically agree with everything you said, despite the fact that we actually do have this use case (but nobody cares unless you are Google or their little brother [1] :)

We have rapidly growing append-only files.  Currently we use gzip Transfer-Encoding to compress an identity range request.  But since T-E went away (again) in h2, it's no longer possible.

I realize it's a controversial issue, but if I understand correctly, h2 is supposed to replace *everything* you could do in 1.1.

As far as I can tell, there are four solutions for maintaining this capability...

1. Julian's bbcc
2. Matthew's DATA frame compression - possibly as an extension now that it was removed from the main spec.
3. My & Christoph's Message-Encoding HTTP extension (an end-to-end version of T-E that is applied after C-E, but before T-E)
4. Keep T-E in h2 (I dare say nobody wants this solution)

[1] http://www.nationmultimedia.com/breakingnews/Google-to-pay-Firefox-almost-1-billion-dollars-in--30172517.html
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Received on Saturday, 21 June 2014 16:35:33 UTC

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