Status element in OAI-PMH envelope, managed authorities declared by registries, and RegTAP

[Markus Demleitner]

Hi Menelaos,

On Tue, Nov 04, 2014 at 12:43:26PM +0100, Menelaus Perdikeas wrote:
> Consider the following scenario: a resource was hosted in a
> registry A and was later, for some reasons, migrated by its owner
> to another registry B. In an IVOA context this should presumably
> also require that the managed authorities of both registries be
> updated to reflect the migration of the resource(s).
> 
> Assuming OAI-PMH support for deletions in repository A, should the
> repository A now report the migrated record as "deleted" or not?
> 
> This has ramifications for RegTAP. When harvesting a repository if
> I see that a record is "deleted" (in the OAI-PMH envelope sense)
> then I proceed to also purge it from the RegTAP database (as per
> RegTAP's requirement that  "deleted" and "inactive" records are not
> maintained - although that "deleted" refers to the "status"
> attribute of the VOResource, not the OAI-PMH envelope's "status"
> element).

The case of a moving authority poses some subtle problems, indeed,
and you are probably right that we need to be more careful in
describing the desired behaviour.

> Does the above make sense? If so, it is important that managed
> authorities declared by registries are correctly maintained when
> resources are migrated (a rare event at any rate).

I believe your treatment makes sense; and of course, maintaining an
essentially perfect registry - authority mapping makes many registry
problems much easier (which is why I propose to give the RofR a
stronger role there).

What I'd suggest as concrete rules for authority moves would look
like:

  (1) Searchable registries detecting a move of an authority from one
  registry to another should schedule a full reharvest of both the
  originating and the receiving registry.

  (2) When an authority moves from one registry to another, deleted
  records should be moved along if at all possible.  The originating
  registry should stop handing out records with the moved authority
  immediately, at least not within its ivo_managed set.  In particular,
  it should not generate deleted records for the records that left the
  registry.

I've put down as much on
http://wiki.ivoa.net/twiki/bin/view/IVOA/RegistryInterfacesNext --
comments, changes and critique welcome there and/or here.

Cheers,

      Markus