GaiaDR2 cross-match with UnWISE returns object ID with wrong unsigned char length

Question

For the catalogs gaia_dr2.x1p5__gaia_source__unwise_dr1__object and unwise_dr1.x1p5__object_gaia_dr2__gaia_source, the UnWISE object ID (for the first catalog is "id2" and for the secon is "id1") has a type of VARCHAR(n) which is an unsigned char with length 16. 

When doing queries to get this specific column (or the full table) from python with the pyvo library, the values for the column are returned with a type of unsigned char with length 1. Therefore every value of the column has only the first character of the string and it's missing the rest.

Could you please check the issue? It is worth mentioning that doing the query from TOPCAT or the Query Interface from Astro Data Lab web page, the column values are returned with the correct length, so looks like it's only affecting python.

Answer 1

Hello, thank you for reaching out. We confirm the behavior you report when querying out TAP service using pyvo. We will fix it in the coming weeks (considering some currently ongoing DB server operations, and staff vacation season at the moment).

In the meantime, we recommend running TAP queries through either of these (some of which you have already pointed out):

- the Data Lab `queryClient` interface (works e.g. in notebooks, Python scripts, etc.)
- the `datalab` command-line utility (works from a local installation)
- web query interface at Data Lab
- other TAP-aware clients, e.g. TOPCAT

Thank you for reporting this, it's much appreciated.
Robert