Example notebooks with query of XTE archive don't work anymore

[matteobachetti]

EDIT: the problem might have been temporary, because one of the workflows I'm running is now working correctly.

Hi,
I'm having problems accessing the archives of several X-ray telescopes. It's maybe easier to show by running the demo_rxte_ml notebook. The notebook executes the following query:

SELECT target_name, cycle, prnb, obsid, time, exposure, ra, dec 
    FROM public.xtemaster as cat 
    where 
    contains(point('ICRS',cat.ra,cat.dec),circle('ICRS',161.26474075372,-59.6844587777,0.1))=1 
    and 
    cat.exposure > 0 order by cat.time

But the result of the execution is

results=tap_services[0].search(query).to_table()

---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
File ~/miniconda3/envs/heasoft/lib/python3.9/site-packages/pyvo/dal/query.py:243, in DALQuery.execute_votable(self, post)
    242 try:
--> 243     return votableparse(self.execute_stream(post=post).read)
    244 except Exception as e:

File ~/miniconda3/envs/heasoft/lib/python3.9/site-packages/astropy/utils/decorators.py:546, in deprecated_renamed_argument.<locals>.decorator.<locals>.wrapper(*args, **kwargs)
    544         warnings.warn(msg, warning_type, stacklevel=2)
--> 546 return function(*args, **kwargs)

File ~/miniconda3/envs/heasoft/lib/python3.9/site-packages/astropy/io/votable/table.py:159, in parse(source, columns, invalid, verify, chunk_size, table_number, table_id, filename, unit_format, datatype_mapping, _debug_python_based_parser)
    156 with iterparser.get_xml_iterator(
    157         source,
    158         _debug_python_based_parser=_debug_python_based_parser) as iterator:
--> 159     return tree.VOTableFile(
    160         config=config, pos=(1, 1)).parse(iterator, config)

File ~/miniconda3/envs/heasoft/lib/python3.9/site-packages/astropy/io/votable/tree.py:3572, in VOTableFile.parse(self, iterator, config)
   3570 config['_current_table_number'] = 0
-> 3572 for start, tag, data, pos in iterator:
   3573     if start:

ValueError: 1:0: syntax error

During handling of the above exception, another exception occurred:

DALFormatError                            Traceback (most recent call last)
Cell In[20], line 1
----> 1 results=tap_services[0].search(query).to_table()

File ~/miniconda3/envs/heasoft/lib/python3.9/site-packages/pyvo/registry/regtap.py:709, in RegistryResource.search(self, *args, **keys)
    704 if not self.service:
    705     raise dalq.DALServiceError(
    706         "resource, {}, is not a searchable service".format(
    707             self.short_name))
--> 709 return self.service.search(*args, **keys)

File ~/miniconda3/envs/heasoft/lib/python3.9/site-packages/pyvo/dal/tap.py:255, in TAPService.run_sync(self, query, language, maxrec, uploads, **keywords)
    228 def run_sync(
    229         self, query, language="ADQL", maxrec=None, uploads=None,
    230         **keywords):
    231     """
    232     runs sync query and returns its result
    233 
   (...)
    253     TAPResults
    254     """
--> 255     return self.create_query(
    256         query, language=language, maxrec=maxrec, uploads=uploads,
    257         **keywords).execute()

File ~/miniconda3/envs/heasoft/lib/python3.9/site-packages/pyvo/dal/tap.py:1073, in TAPQuery.execute(self)
   1059 def execute(self):
   1060     """
   1061     submit the query and return the results as a TAPResults instance
   1062 
   (...)
   1071        for errors parsing the VOTable response
   1072     """
-> 1073     return TAPResults(self.execute_votable(), url=self.queryurl, session=self._session)

File ~/miniconda3/envs/heasoft/lib/python3.9/site-packages/pyvo/dal/query.py:246, in DALQuery.execute_votable(self, post)
    244 except Exception as e:
    245     self.raise_if_error()
--> 246     raise DALFormatError(e, self.queryurl)

DALFormatError: ValueError: 1:0: syntax error

Has anything changed in the language? In any case, I think the example notebooks should be updated because they don't work anymore.

[zoghbi-a]

Thanks @matteobachetti for reporting the issue.
This looks like a transient server error. In these cases, trying again or at a later time can fix it.

The notebooks are being updated (#13), so if the error persists, please let us know.

[matteobachetti]

Thanks for checking @zoghbi-a!