Clarification on ObsCore 1.1 Specification

[Molinaro, Marco]

Hi,

actually, point 2. pol_states, is already covered by an erratum, erratum-2:

https://wiki.ivoa.net/twiki/bin/view/IVOA/ObsCore-1_1-Erratum-2

Cheers
    Marco

Il giorno gio 15 ott 2026 alle ore 11:57 Markus Demleitner via dm <
dm at ivoa.net> ha scritto:

> Hi Phelokazi,
>
> On Thu, Oct 08, 2026 at 12:36:07PM +0000, Phelokazi Dube via dm wrote:
> > I am currently working on implementing an ObsCore/ObsTAP service
> > for the Southern African Large Telescope (SALT) at the South
> > African Astronomical Observatory (SAAO), using DaCHS as our Virtual
>
> [disclosure: main DaCHS developer speaking here]
>
> > 1. pol_xel datatype — INTEGER or BIGINT?
> > In Table 4 (TAP Implementation of ObsCoreDM), the datatype for
> > pol_xel is specified as adql:BIGINT. However, the version change
> > history indicates that the datatype was changed from BIGINT to
> > INTEGER. Could you please confirm which datatype is intended for
> > pol_xel?
>
> DaCHS used to have bigint until a while ago
> (<http://blog.g-vo.org/queries-against-my-obscore-are-slow-.html> has
> a bit of background).  The hard-coded sizes have been a topic before
> <http://mail.ivoa.net/pipermail/dm/2016-June/005408.html>, but then
> somehow we failed to update the spec accordingly.
>
> My take: We'll have string/integer types as in RegTAP
> <https://ivoa.net/documents/RegTAP/20241002/REC-RegTAP-1.2.html#tth_sEc8>
> in the next minor version, and hence you shouldn't need to worry.
> Current (I think) versions of the stilts TAP validator accept any
> integer type for these columns.
>
> > 2. pol_states — Mandatory or optional?
> > In Appendix B, Table 5 (Data Model Summary), the pol_states field
> > is marked MAN = NO, indicating that it is optional. However,
> > Section B.6.5.1 (List of Polarization States) describes pol_states
> > as a mandatory field, with NULL permitted when polarization is not
> > applicable. Could you please clarify whether pol_states is
> > mandatory or whether its optional?
>
> DaCHS includes pol_states, and it would be fairly non-trivial for you
> to remove it.  May I ask why this bothers you (except that the spec
> needs to be fixed, of course)?
>
> Other than that I'd say the inconsistency is a case for a bug
> against obscore <https://github.com/ivoa-std/ObsCore/issues>-
>
> Thanks,
>
>          Markus
>
>

-- 
Marco Molinaro
INAF - Istituto Nazionale di AstroFisica
Osservatorio Astronomico di Trieste
email marco.molinaro at inaf.it
tel. [+39] 333 33 20 564 [also Telegram]
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