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Re: PaceBatch and pipelining

On Sun, Jun 26, 2005 at 10:25:48PM -0700, Tim Bray wrote:
> On Jun 26, 2005, at 7:40 PM, Mark Baker wrote:
> 
> >Moreover, the
> >problems with batching non-idempotent requests isn't at all  
> >specific to
> >HTTP pipelining, it's just inherrent to any batch mechanism, including
> >PaceBatch.  That is, if you POST a BatchRequest with two app:Post
> >requests embedded, you're going to have exactly the same issues as
> >with two pipelined HTTP POST requests.
> 
> Except for, PaceBatch recognizes that partial success is a  
> possibility and specifies measures (no re-using URIs) to limit the  
> damage.

Hmm, I can't seem to find that in the Pace, but it seems like it could
be a useful restriction.  Is there any reason we couldn't just provide
the same advice when using pipelining?

>Curious: is there any prior art in using HTTP to do this  
> kind of thing?

Dunno.

> >So I'm -1 on PaceBatch, but I'd support APP calling out the use of  
> >HTTP
> >pipelining for batching purposes (with a caveat about going against  
> >the
> >SHOULD NOT recommendation from 2616, of course).
> 
> So, let me see... we could adopt an approach which is limited to HTTP  

Last time I checked, APP was still HTTP based (8-), so I see no problem
in leveraging another existing, battle tested, widely implemented,
HTTP-specific feature.

> while flying in the face of a SHOULD in its RFC,

I responded to that point already, so won't repeat it here, except to
say that I believe this Pace should say that BatchRequests SHOULD NOT
include non-idempotent operations (such as app:Post).

> one which which breaks no rules and is potentially usable on a wide  
> variety of protocols including HTTP.  Seems like a no-brainer to me.   
>
> (Assuming we believe there's a real quantitative optimization to be  
> had). -Tim

Yes, that's good to keep in mind.

Mark.
-- 
Mark Baker.  Ottawa, Ontario, CANADA.          http://www.markbaker.ca
Coactus; Web-inspired integration strategies   http://www.coactus.com