Asynchronous querying and tabular data
dtody at nrao.edu
Tue May 1 13:46:12 PDT 2007
Of course async and VOSpace go together, but a subtle issue here is
what exactly it means to store a table in VOSpace. Is the table stored
as a DBMS table managed by the VOSpace, or as a file (e.g., a VOTable)?
Probably the former, with serialization occuring only at access time,
e.g., when a remote client retrieves the table. Hence TAP would compute
the output table, and somehow hand it off to the local VOSpace, which
would manage it thereafter. If the output VOSpace is remote, then is
the table serialized for transfer, and in so in what format? Is it
ingested and stored as a file or as a DBMS table on the remote VOSpace?
If ultimately we want to be able to upload large tables to be used in a
query, or store output tables as intermediate results, then the VOSpace
will want to at least be co-located on the same DBMS. As you suggest,
TAP and VOSpace could probably be separate services however.
On Tue, 1 May 2007, Patrick Dowler wrote:
> Agreed. On a practical level this means we don't have to define all the stuff
> VOSpace can do and -- more importantly even -- it is easier for the TAP
> implemention to be a VOSpace client than manage the resources necessary to
> stage the result itself. you can write a more or less stateless TAP service
> where a request has a finite lifetime and you don't have to do cleanup and
> resource management later on.
> On Tuesday 01 May 2007 13:00, Alex Szalay wrote:
> > I think that when we get into the async responses, this will
> > have to be part of the VOStore/VOSpace story, i.e. the output
> > goes into a friendly VOSpace location and sends the handle
> > to the result.
> > --Alex
> Patrick Dowler
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