TAP 1.0: sync vs async

[Guy Rixon]

Hi Gerard,

I support your suggestion that the VOSI resources be siblings of the  
TAP sync and async resources.

This was discussed at length in the drafting of TAP 0.3x, but the  
editors did not get a consensus in favour, only a majority.

Separating the VOSI resources has an important advantage: the  
capabilities and tables resources can then be implemented as a static  
XML-document. When VOSI is combined with the TAP-query resources,  
requests for capabilities and tables have to be generated (or at least  
mediated) by servlets or scripts.

I note that the VOSI spec doesn't mandate any particular URL for the  
VOSI resources. Including them in sync is allowed; separating them is  
also OK.

Cheers,
Guy

On 16 Jul 2009, at 10:24, Gerard wrote:

> Dear colleagues
>
> In the recent interop the issue of whether support for synchronous  
> queries
> should be mandated, or async, or both was mentioned, but not really
> discussed further in the relevant sessions. I would like to once  
> more bring
> this up though.
>
> My proposal is still that we mandate that sync OR async is  
> supported, or
> both.
>
> There are use cases where sync allone suffices, and whatever some  
> experts
> argue, sync is easier to support in a robust manner than async.
> On the other hand there are use cases where async is clearly the best
> option, and sync might never be desired, so async alone should also be
> possible.
> We have had discussions on the mailing lists some months ago and I  
> guess we
> do not need to rehash those.
>
> One "argument" against leaving it optional to support sync is that  
> the VOSI
> requests are currently implemented on the sync/ end point.
> Irrespective of how we decide on sync vs async, I propose the VOSI  
> requests
> should NOT be put on top of the sync/ end point, but "next to" sync/  
> and
> async/. They are different things from the actual service requests and
> should/need not be mixed with them.
>
> All these points were discussed with various people right after the  
> closing
> of the interop, when I realised that they had not been discussed.
> There was general agreement (about 8 people were included in the  
> discussion,
> I will keep their identities secret) on all these points.
> I promised to bring this up during the RFC, so here you have it.
>
> Best regards
>
> Gerard