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Re: About draft-nottingham-http-pipeline-01.txt

From: Brian Pane <brianp@brianp.net>
Date: Wed, 4 May 2011 19:04:57 -0700
Message-ID: <BANLkTi=gG=zVXx4chvHvwQuoSZBiEs0h1Q@mail.gmail.com>
To: HTTP Working Group <ietf-http-wg@w3.org>
On Wed, Apr 27, 2011 at 12:13 AM, Mark Nottingham <mnot@mnot.net> wrote:
> On 27/04/2011, at 10:43 AM, Brian Pane wrote:
>> On Mon, Apr 25, 2011 at 11:56 PM, Mark Nottingham <mnot@mnot.net> wrote:
>> [...]
>>> A fair amount of time has passed since the first version (or even most
>>> recent version!) of the draft, and in my conversations with vendors --
>>> especially Moz's Patrick McManus -- I've come to realise that the draft
>>> is probably too conservative. I.e., There's a desire to have pipelining on
>>> by default, without any opt-in or special mechanisms from the server,
>>> using heuristics to back off if a problem is encountered.
>> Does this also imply the use of heuristics up-front to decide whether a
>> given request is a suitable candidate for pipelining?  E.g., I can imagine
>> a client implementation doing something like this: "if method is GET and
>> request-URI doesn't contain a query string and the request was not
>> issued via JavaScript then assume it's safe to pipeline."  If so, I also
>> anticipate that web app developers will start designing toward the
>> browsers' heuristics.
> Well, nothing prohibits a browser from doing that, but the heuristics
> that I'm seeing are very carefully watching for errors and slowdowns,
> and adjusting appropriately.

What sort of adjustment semantics are you seeing?  If a client issues
pipelined requests R1 through Rn and then detects a problem with R1 (slow
or malformed response), I'm assuming it will just continue awaiting responses
for R2 through Rn; the client can't reissue those requests on different
connections because it can't tell whether the server has begun processing
them, and it doesn't know whether the processing is idempotent.

Received on Thursday, 5 May 2011 02:05:44 UTC

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