[jsdl-wg] [Fwd: Proposed extension]

[Donal K. Fellows]

Peter Lane wrote:
> I also think the ID attribute is perhaps redundant. JobIdentification  
> has a JobName element that seems like it should be sufficient for  
> uniquely identifying a subjob. Or is this not how the authors  
> envisioned JobName's use?

Actually, the problem with an ID attribute is more subtle, in that the
uniqueness constraint upon it is defined purely at the document level.
In the world of XML documents living at URLs, the wider disambiguation
is done by the URL of the overall document, but that's not useful with
JSDL because job submission templates will typically not have a (fixed)
URL before the submission. I suspect that to fix this we need a GUID
*somewhere* in there, and that the source of the GUID has to be either
the user or (more likely) the client software that injects the JSDL
document into the system. That would allow JSDL consumers to know
unambiguously whether they've seen the document before without having to
do a full canonicalize-and-compare. With a bit of work[*], I might even
come up with a scenario where a full comparison would fail despite two
JSDL documents really being the "same" in some higher-level sense.
Things get quite complex when you have job rewriting/optimization
services in the mix, but a GUID lets the "what is identity" decision be
taken at a the outermost - and hence most abstract - level.

Donal.
[* Which I'd rather not do, being somewhat lazy. :-) ]