[provenance-challenge] Re: Optional Query 9

[Ben Clifford]

On Mon, 27 Apr 2009, Robert Clark wrote:

> I wanted to raise an objection I have to suggested query nine and see 
> what kind of responses my objection yields.
> 
> Which steps were not executed because of halt?
> 
> I believe this is *not* a provenance query, it asks a question about 
> what may have happened in the future not a question about what has 
> happened in the past. To me, this query seems more at home in a workflow 
> system study rather than a challenge studying the interoperability of a 
> provenance model.

I am of the same opinion (probably because our system cannot easily answer 
this ;)

VDS, which was the predecessor project to Swift, could probably have 
answered this with its Virtual Data Catalog because it preloaded workflow 
steps. However, Swift, my present project, cannot easily answer this, as 
in many cases we do not know what future steps will be without evaluating 
a SwiftScript program further, something we don't/can't do if some part 
has failed.

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