Re: CORBA performance - why CORBA

[Diego Sevilla Ruiz <dsevilla um es>]

Hello all!

On Wed, 5 Dec 2001, Bart Schuller wrote:

> On Mon, Dec 03, 2001 at 11:53:23PM -0500, Michael Meeks wrote:
> > On 3 Dec 2001, Havoc Pennington wrote:
> > >   b) to avoid round trips; I'd like for example a "set key to value"
> > >      operation to be oneway (yeah I could just put oneway
> > >      on all existing methods, for this).
> > 
> >         Quite; oneway is great.
> 
> I don't understand why I keep hearing this, when CORBA itself doesn't
> guarantee message delivery for oneway calls. Sure, Orbit may give that
> guarantee (how can it?), but ignoring this is precisely the kind of
> transparency that is actually a dangerous simplification.
> 

Yes, oneway messages (and their specification in IDL files) has been
traditionally treated as a bad adition to IDL. The same topic was
discussed here a year or so ago. Some of these problems lead to the
implementation of ORBit2, I think.

	There are several problems with oneway messages, including
non-guaranteed delivery and that asynchrony is an implementation concept
that it's specified in an only-declarative language as is IDL.

	These problems and others can be found in Vinoski&Schmidt article:
http://www.iona.com/hyplan/vinoski/col15.pdf

	In addition, there are others of the same series: 

http://www.iona.com/hyplan/vinoski/col16.pdf
http://www.iona.com/hyplan/vinoski/col17.pdf
http://www.iona.com/hyplan/vinoski/col19.pdf

	Perhaps, it's time now, with ORBit2, to implement some kind of
asynchrony following the OMG standard for it (as commented out in the
articles).

	The idea behind it is allowing the client deciding the asynchrony
of its invocations regardless of the contract (IDL) used.

	Best regards.
	diego.

--
Diego Sevilla Ruiz -- http://ditec.um.es/~dsevilla/ -- dsevilla um es
Dep. Ingeniería y Tecnología de Computadores, Facultad de Informática
Univ.de Murcia,Campus Espinardo,30080 Murcia (SPAIN),Tel.+34968367658
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