notes from Session 1 of Interop

[Ray Plante]

Hi RWGers,

For the benefit of thoses who could not attend the first Registry session 
at the Interop in Victoria, here are the notes (appended below).  For more 
information about Registry WG work at the the Interop can be found at 
http://www.ivoa.net/cgi-bin/twiki/bin/view/IVOA/InterOpMay2010Reg.

Note that this week we have two special sessions on Validation and 
Verification where we are discussioning related issues.  See 
http://www.ivoa.net/cgi-bin/twiki/bin/view/IVOA/InterOpMay2010Val

cheers,
Ray

Session 1: VOResource Extensions: VOStandard, RegSimpleDAL (Tuesday, 2pm)

Agenda:
   Status on Current Efforts: VOStandard and RegSimpleDAL     RayPlante
   Accessing the Registry From TOPCAT 	                     Mark Taylor
   Registry Searchin in Heliophysics VxO                      Kevin Benson
   Discussion: Future Standards Efforts

New Naming convention:

We had been advised by the TCG to consider renaming VOStandard as this 
name could be confused with the IVOA Document Standards among those 
outside of the the Registry Working Group. RegSimpleDAL was observed to be 
more mysterious. We came up with a new convention for short names for RWG 
standards that are focussed on defining a registry extension and which 
would be applied to these two standards: subject + RegExt.

Thus, VOStandard will now be referred to as StandardsRegExt, and 
RegSimpleDAL will be referred to as SimpleDALRegExt?. Ray will update the 
relevent documents and twiki pages.

RegSimpleDAL/SimpleDALRegExt

     * If necessary, SSA will be split out of this document if necessary
       changes for this extension cannot be incorporated into this document
       when it is otherwise ready for PR.

     * We should be sure this document includes a statement that accessURL
       values should end in either a ? or a &

The Search interface

     * See Mark's slides for the Topcat experience
           o Mark uses the ivoaregistry Java library which returns results
             in DOM; the memory requirements can be quite large
           o One UKIDSS record is 11 MB
           o He replaced the DOM part with SAX streaming to extract the few
             things he was interested in
           o He offered to make this code available
     * Interest was expressed in his SAX streaming; Ray would like to get
       it into ivoaregistry.
     * A common use case for applications is to extract a small part of the
       description in a light-weight way. Any new search interface we
       consider should allow the client ask for the desired items.

Registry Interoperability

     * Mark: serious problem with Euro-VO registry: use of LIKE in ADQL
       searches are case-sensitive.
           o errata to RI on this point?
     * dynamic discovery of Registries via the standard search interface is
       apparently broken with all registries.

Future Standards Efforts

With modest but persistent effort, we can easily complete the two pending 
standards in the next six months. Where should we go from here? Here are 
some thoughts from past IVOA discussions:

     * VOApplications, an extension for registering tools, applications and
       software libraries, has been on our roadmap; however, last fall we
       concluded that motivation for registering applications was not very
       strong. Thus, this standard has been tabled for now. Has our outlook
       changed since then?
     * The constraint-based search interface is less than desirable. Can we
       do something better?
     * Standard for search results in VOTable format
     * We would like to recognize and endorse Astronomical Visualization
       Metadata (AVM) as a standard.

We also have real need to put effort into operational kinds of activities 
(the theme for Thursday). Given limited person-power, how important are 
the potential new standards, compared to curation, validation of our 
current assets?

Ray:  Current assessment of full constraint-based search interface:
   - Current based on deprecated version of ADQL
   - Certain kinds of query not possible
   + searching on any item is possible without change to standard

New search interface should include:
   + searching on any item (or future item) without change to standard
   + from Mark: ability to select what information to return

Possible directions:
   o  push XQuery for relational databases
   o  VOExplorer's Google-like syntax (title:LMC ability:TAP)
       +comment: it is sufficient to expose this at the tool level; rather
                 than server interface level.
   o  ...

Kevin Benson shared some slides borrowed from a talk he saw about the 
Heliophysics VxO.  This community is considering a Lucene-based syntax.