Asynchronous querying and tabular data
szalay at jhu.edu
Tue May 1 13:57:06 PDT 2007
My take n this would be that the VOSpace is bytes-in, bytes-out. If we 'put'
a certain pattern of bytes that happens to be a VOTable, we should get back
EXACTLY the same bytes when we 'get' it.
From: owner-voql-teg at eso.org [mailto:owner-voql-teg at eso.org] On Behalf Of
Sent: Tuesday, May 01, 2007 4:46 PM
To: Patrick Dowler
Cc: voql-teg at ivoa.net
Subject: Re: Asynchronous querying and tabular data
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
> Tel/Tél: (250) 363-6914 | fax/télécopieur: (250) 363-0045
> Canadian Astronomy Data Centre | Centre canadien de donnees
> astronomiques National Research Council Canada | Conseil national de
> Government of Canada | Gouvernement du Canada
> 5071 West Saanich Road | 5071, chemin West Saanich
> Victoria, BC | Victoria (C.-B.)
More information about the voql-teg