summary of recent RI discussion

[Paul Harrison]

Ray Plante wrote:
> Hi RWGers,
> 
> I thought I would try to summarize what I think is the state of the 
> various discussion threads.  I wasn't sure until I started looking back at 
> the discussion, but we actually have made some progress.  Here's my 
> summary, segregated by topic.
> 
> 1. ownedAuthority ==> registry of registries
> 
> We ressurected the discussion of an <ownedAuthority> tag as part of a 
> mechanism for determining what registries to harvest from and aggregating 
> the harvesting at the national/regional level.  The various solutions 
> posed suffered from a certain amount of complexity.  Bob Hanisch suggested 
> that the IVOA sponsor a "registry of registries": a small registry 
> containing only Registry records.  It provides a central place for 
> publishers to register their publishing registries and full registries a 
> place to find out how to publish from.  
> 
> The idea of aggregating the harvesting was dropped given the simplicity of
> this new mechanism: the number of registries to harvest from might be in
> the low tens.  Thus, <ownedAuthority> is not needed.  This idea also
> eliminates the need for a harvester interface, which currently included a
> harvest() function and possibly a getRegistries() function.

Surely the separation of the owned Authority and searchable Authority 
concept is still needed even by the registry of registries fully to 
describe what is out there.  As well as <Registry> records, it needs to 
contain <Authority> records, and I rather liked your idea to have an 
element in the Authority that points to the "owning" registry, which 
would fulfil this role. The "managedAuthority" elements in each of the 
Registry elements would then be the list of authorityIDs that were 
searchable in a particular registry (i.e. the set of harvested, and 
owned AuthorityIDs). There are several use cases this model can support, 
that are needed by the current set of registry implementations/deployments.

1. A registry can "own"/publish more than one Authority
2. Not all registries will be able to support all specialized schema 
extensions, so it will not be the case that all registries are equal - 
i.e. it will not be possible to create an "uber"-registry that could 
satisfy any query by harvesting from all the publishing registries. The 
registry of registries does allow an agent to discover which of the 
registries can service a query for a particular AuthorityID.

I still think that it might be better to replace the term "managed" with 
"searchable"  in these discussions, because I think that "manage" has 
meant "own" to some people.
> 
> 2. harvesting all vs. managed 
> 
> We all like the idea of being able to get all records from a registry or
> just those that originated from that registry.  It was agreed to define an
> OAI set called "ivo_managed" to harvest the latter subset.

It is a good idea, but should be used with caution if the aim is then 
for a searchable registry to claim to manage all of the harvested 
records, as (see my point 2 above) the registry might not be able to 
"understand" all of the schema extensions enough to be able to pass them on.



-- 
Paul Harrison
ESO Garching
www.eso.org