Votable status

[Laurent Bourgès]

Dear all,

I would like to give my comments about the VOTable standard (1.2) and its
new revision 1.3 in order to simplify the standard document (i.e. make
optional or minor items deprecated) and clarify many topics (explanations,
use cases).

Could you remind me links to VOTable 1.3 documentation (wiki page,
documents) ?

FYI, I started working with andre schaff on the new Savot implementation
(4.0) first to fix performance issues and also to add missing features
(Binary, datatype handling, id / name / reference resolver ...)

Recently I looked in depth at the standard related to DATA handling,
encodings (base64, gzip) on BINARY (or TD) and I advocate many points were
fuzzy to me:
- which BINARY encoding must be supported by implementation ?
- which are concrete rules / best practices related to data encoding /
decoding as VOTable ?
- who is using VOTable extensions (XMLDATA or TD encoding) ?
- what means gzip encoding in a xml document (gzip + base64) ? why it is
better than base64 + complete votable document compression (gzip or http
compression) ?

About compression: very huge TABLEDATA can be compressed (gzip) much more
than BINARY (base64) or (gzip) because compression does not work well on
binary streams.

Of course, dealing with very huge TABLEDATA requires an efficient VOTable
parser (partial parsing) and consume data on the fly (to avoid allocating
all data in memory first). Savot 4 will support a new ROW_READ mode to
parse only one row at a time.

Laurent
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