ENH: Update pandas-gbq to 0.10.0.

Author: tswast

doc/source/whatsnew/v0.25.0.rst

@@ -191,6 +191,8 @@ Optional libraries below the lowest tested version may still work, but are not c
 +-----------------+-----------------+
 | openpyxl        | 2.4.0           |
 +-----------------+-----------------+
+| pandas-gbq      | 0.10.0          |
++-----------------+-----------------+
 | pyarrow         | 0.9.0           |
 +-----------------+-----------------+
 | pytables        | 3.4.2           |
@@ -364,6 +366,7 @@ I/O
 - Improved the explanation for the failure when value labels are repeated in Stata dta files and suggested work-arounds (:issue:`25772`)
 - Improved :meth:`pandas.read_stata` and :class:`pandas.io.stata.StataReader` to read incorrectly formatted 118 format files saved by Stata (:issue:`25960`)
 - Fixed bug in loading objects from S3 that contain ``#`` characters in the URL (:issue:`25945`)
+- Updated :func:`read_gbq` to version 0.10.0 of the ``pandas-gbq`` library. Adds ``use_bqstorage_api`` parameter to speed up downloads of large data frames.
 
 Plotting
 ^^^^^^^^

pandas/io/gbq.py

@@ -26,7 +26,7 @@ def _try_import():
 def read_gbq(query, project_id=None, index_col=None, col_order=None,
              reauth=False, auth_local_webserver=False, dialect=None,
              location=None, configuration=None, credentials=None,
-             private_key=None, verbose=None):
+             use_bqstorage_api=None, private_key=None, verbose=None):
     """
     Load data from Google BigQuery.
 
@@ -103,6 +103,20 @@ def read_gbq(query, project_id=None, index_col=None, col_order=None,
         *New in version 0.8.0 of pandas-gbq*.
 
         .. versionadded:: 0.24.0
+    use_bqstorage_api : bool, default False
+        Use the `BigQuery Storage API
+        <https://cloud.google.com/bigquery/docs/reference/storage/>`__ to
+        download query results quickly, but at an increased cost. To use this
+        API, first `enable it in the Cloud Console
+        <https://console.cloud.google.com/apis/library/bigquerystorage.googleapis.com>`__.
+        You must also have the `bigquery.readsessions.create
+        <https://cloud.google.com/bigquery/docs/access-control#roles>`__
+        permission on the project you are billing queries to.
+
+        This feature requires the ``google-cloud-bigquery-storage`` and
+        ``fastavro`` packages.
+
+        .. versionadded:: 0.25.0
     private_key : str, deprecated
         Deprecated in pandas-gbq version 0.8.0. Use the ``credentials``
         parameter and
@@ -131,22 +145,13 @@ def read_gbq(query, project_id=None, index_col=None, col_order=None,
     """
     pandas_gbq = _try_import()
 
-    if dialect is None:
-        dialect = "legacy"
-        warnings.warn(
-            'The default value for dialect is changing to "standard" in a '
-            'future version of pandas-gbq. Pass in dialect="legacy" to '
-            "disable this warning.",
-            FutureWarning,
-            stacklevel=2,
-        )
-
     return pandas_gbq.read_gbq(
         query, project_id=project_id, index_col=index_col,
         col_order=col_order, reauth=reauth,
         auth_local_webserver=auth_local_webserver, dialect=dialect,
         location=location, configuration=configuration,
-        credentials=credentials, verbose=verbose, private_key=private_key)
+        credentials=credentials, use_bqstorage_api=use_bqstorage_api,
+        verbose=verbose, private_key=private_key)
 
 
 def to_gbq(dataframe, destination_table, project_id=None, chunksize=None,

pandas/tests/io/test_gbq.py

@@ -90,18 +90,6 @@ def make_mixed_dataframe_v2(test_size):
                      index=range(test_size))
 
 
-def test_read_gbq_without_dialect_warns_future_change(monkeypatch):
-    # Default dialect is changing to standard SQL. See:
-    # https://github.com/pydata/pandas-gbq/issues/195
-
-    def mock_read_gbq(*args, **kwargs):
-        return DataFrame([[1.0]])
-
-    monkeypatch.setattr(pandas_gbq, 'read_gbq', mock_read_gbq)
-    with tm.assert_produces_warning(FutureWarning):
-        pd.read_gbq("SELECT 1")
-
-
 @pytest.mark.single
 class TestToGBQIntegrationWithServiceAccountKeyPath(object):