Pinot BIG_DECIMAL columns are not accessible via SQLAlchemy

[keriharris]

When retrieving Pinot table metadata with sqlalchemy the Pinot BIG_DECIMAL type is not currently supported. This prevents Apache SuperSet from creating datasets for any Pinot tables that contain BIG_DECIMAL columns. The following code triggers this:

from sqlalchemy import *
from sqlalchemy.engine import create_engine

engine = create_engine("pinot+http://<broker_host>:<broker_port>/query/sql?controller=http://<controller_host>:<controller_port>/")
conn = engine.connect()
metadata = MetaData()
t = Table("mytable", metadata, autoload_with=conn)

This results in the following error:

Traceback (most recent call last):
  File "/home/keri/testbed/test.py", line 23, in <module>
    t = Table("arm_commission", metadata, autoload_with=conn)
  File "<string>", line 2, in __new__
  File "/path/to/sqlalchemy/util/deprecations.py", line 277, in warned
    return fn(*args, **kwargs)  # type: ignore[no-any-return]
  File "/path/to/sqlalchemy/sql/schema.py", line 432, in __new__
    return cls._new(*args, **kw)
  File "/path/to/sqlalchemy/sql/schema.py", line 486, in _new
    with util.safe_reraise():
  File "/path/to/sqlalchemy/util/langhelpers.py", line 147, in __exit__
    raise exc_value.with_traceback(exc_tb)
  File "/path/to/sqlalchemy/sql/schema.py", line 482, in _new
    table.__init__(name, metadata, *args, _no_init=False, **kw)
  File "/path/to/sqlalchemy/sql/schema.py", line 858, in __init__
    self._autoload(
  File "/path/to/sqlalchemy/sql/schema.py", line 890, in _autoload
    conn_insp.reflect_table(
  File "/path/to/sqlalchemy/engine/reflection.py", line 1535, in reflect_table
    _reflect_info = self._get_reflection_info(
  File "/path/to/sqlalchemy/engine/reflection.py", line 2014, in _get_reflection_info
    columns=run(
  File "/path/to/sqlalchemy/engine/reflection.py", line 2000, in run
    res = meth(filter_names=_fn, **kw)
  File "/path/to/sqlalchemy/engine/reflection.py", line 928, in get_multi_columns
    table_col_defs = dict(
  File "/path/to/sqlalchemy/engine/default.py", line 917, in _default_multi_reflect
    single_tbl_method(
  File "/path/to/pinotdb/sqlalchemy.py", line 252, in get_columns
    columns = [
  File "/path/to/pinotdb/sqlalchemy.py", line 255, in <listcomp>
    "type": get_type(spec["dataType"], spec.get("fieldSize")),
  File "/path/to/pinotdb/sqlalchemy.py", line 329, in get_type
    return type_map[data_type.lower()]
KeyError: 'big_decimal'

[xiangfu0]

Thanks for reporting!
Yes, this new data type is not yet supported in the lib. We will add it soon.