new RI document

[Paul Harrison]

On 16.06.2006, at 13:50, Ray Plante wrote:

>
> I think we're making the wrong analogy here.  People don't expect  
> Google
> to return the exact same results for a set of words as, say,  
> Ask.com or
> Yahoo or any other search engine.

They do not have an interface document and a content data model that  
make a claim to them being similar to one another - IVOA registries do.

> The reason is because each uses
> different searching and sorting algorithms behind the scenes.  That  
> is the
> very reason we have different results from our registries.
>
> (Nor, BTW, do users expect Google to return the same answer to the  
> same
> keywords two days in a row.)

No because they understand that the data that they are searching is  
changing rapidly - a fair analogy would be to ask would people expect  
two queries that they fired simultaneously at two google servers (if  
there were 2) to return the same results?

> The choice of the mandatory list was taken in the spirit of what  
> are the
> minimal requirements we place on a registry to call it compliant and
> interoperable.

but as soon as a registry choses to implement the keyword search over  
a key outside the mandatory set it becomes non-interoperable = does  
not behave in the same way for that interface call.

> Furthermore, that difference in behavior is how they attract users-- 
> they
> try to give the best results for their target community.  Now we  
> shouldn't
> think of our registries as in competition for users; however,  
> registries
> do need to be able to innovate and gradually improve the  
> effectiveness of
> the keyword search.  And there are a number of very useful  
> techniques that
> could be added, such as Soundex, as Noel suggested.  However, these  
> can
> get complex, and there's no way we can mandate their use across  
> different
> implementations and back-end databases.

Indeed - I am all for innovation, and the new 1.0 services  
registration  model would allow for a registry to do precisely that -  
if they want to implement a better search, then they can publish an  
extra interface that does the better searching, whilst still doing  
the standard stuff (and no more) in the standard interface.

The whole motivation for the keyword search operation is simplicity -  
it is simpler both for the implementor and the client user if the  
list of fields searched is closed and fixed.

It is a common complaint amongst client software writers that IVOA  
services have too many "optional" features and the "core" of the  
service is too weak e.g. David Schade's comments on http:// 
www.ivoa.net/twiki/bin/view/IVOA/InterOpMay2006Architecture - and  
there are more who share this view...

Paul.