superset: Oracle backend: pandas Exception : KeyError

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/local/Python-3.5.2/lib/python3.5/site-packages/caravel/views.py", line 827, in explore
    payload = obj.get_json()
  File "/usr/local/Python-3.5.2/lib/python3.5/site-packages/caravel/viz.py", line 294, in get_json
    'data': self.get_data(),
  File "/usr/local/Python-3.5.2/lib/python3.5/site-packages/caravel/viz.py", line 479, in get_data
    return self.get_df().to_html(
  File "/usr/local/Python-3.5.2/lib/python3.5/site-packages/caravel/viz.py", line 474, in get_df
    margins=True,
  File "/usr/local/Python-3.5.2/lib/python3.5/site-packages/pandas/tools/pivot.py", line 120, in pivot_table
    grouped = data.groupby(keys)
  File "/usr/local/Python-3.5.2/lib/python3.5/site-packages/pandas/core/generic.py", line 3778, in groupby
    **kwargs)
  File "/usr/local/Python-3.5.2/lib/python3.5/site-packages/pandas/core/groupby.py", line 1427, in groupby
    return klass(obj, by, **kwds)
  File "/usr/local/Python-3.5.2/lib/python3.5/site-packages/pandas/core/groupby.py", line 354, in __init__
    mutated=self.mutated)
  File "/usr/local/Python-3.5.2/lib/python3.5/site-packages/pandas/core/groupby.py", line 2383, in _get_grouper
    in_axis, name, gpr = True, gpr, obj[gpr]
  File "/usr/local/Python-3.5.2/lib/python3.5/site-packages/pandas/core/frame.py", line 1997, in __getitem__
    return self._getitem_column(key)
  File "/usr/local/Python-3.5.2/lib/python3.5/site-packages/pandas/core/frame.py", line 2004, in _getitem_column
    return self._get_item_cache(key)
  File "/usr/local/Python-3.5.2/lib/python3.5/site-packages/pandas/core/generic.py", line 1350, in _get_item_cache
    values = self._data.get(item)
  File "/usr/local/Python-3.5.2/lib/python3.5/site-packages/pandas/core/internals.py", line 3290, in get
    loc = self.items.get_loc(item)
  File "/usr/local/Python-3.5.2/lib/python3.5/site-packages/pandas/indexes/base.py", line 1947, in get_loc
    return self._engine.get_loc(self._maybe_cast_indexer(key))
  File "pandas/index.pyx", line 137, in pandas.index.IndexEngine.get_loc (pandas/index.c:4154)
  File "pandas/index.pyx", line 159, in pandas.index.IndexEngine.get_loc (pandas/index.c:4018)
  File "pandas/hashtable.pyx", line 675, in pandas.hashtable.PyObjectHashTable.get_item (pandas/hashtable.c:12368)
  File "pandas/hashtable.pyx", line 683, in pandas.hashtable.PyObjectHashTable.get_item (pandas/hashtable.c:12322)
KeyError: 'agent_name'