def _try_fetch(self, size=None):
"""Try to start fetching data, if not yet started.
Mutates self to indicate that iteration has started.
"""
if self._query_job is None:
raise exceptions.InterfaceError(
"No query results: execute() must be called before fetch.")
if self._query_job.dry_run:
self._query_data = iter([])
return
is_dml = (self._query_job.statement_type
and self._query_job.statement_type.upper() != "SELECT")
if is_dml:
self._query_data = iter([])
return
if self._query_data is None:
client = self.connection._client
bqstorage_client = self.connection._bqstorage_client
if bqstorage_client is not None:
rows_iterable = self._bqstorage_fetch(bqstorage_client)
self._query_data = _helpers.to_bq_table_rows(rows_iterable)
return
rows_iter = client.list_rows(
self._query_job.destination,
selected_fields=self._query_job._query_results.schema,
page_size=self.arraysize,
)
self._query_data = iter(rows_iter)
def _try_fetch(self, size=None):
"""Try to start fetching data, if not yet started.
Mutates self to indicate that iteration has started.
"""
if self._query_job is None:
raise exceptions.InterfaceError(
"No query results: execute() must be called before fetch.")
is_dml = (self._query_job.statement_type
and self._query_job.statement_type.upper() != "SELECT")
if is_dml:
self._query_data = iter([])
return
if self._query_data is None:
client = self.connection._client
bqstorage_client = self.connection._bqstorage_client
if bqstorage_client is not None:
try:
rows_iterable = self._bqstorage_fetch(bqstorage_client)
self._query_data = _helpers.to_bq_table_rows(rows_iterable)
return
except google.api_core.exceptions.GoogleAPICallError as exc:
# NOTE: Forbidden is a subclass of GoogleAPICallError
if isinstance(exc, google.api_core.exceptions.Forbidden):
# Don't hide errors such as insufficient permissions to create
# a read session, or the API is not enabled. Both of those are
# clearly problems if the developer has explicitly asked for
# BigQuery Storage API support.
raise
# There is an issue with reading from small anonymous
# query results tables. If such an error occurs, we silence
# it in order to try again with the tabledata.list API.
_LOGGER.debug(
"Error fetching data with BigQuery Storage API, "
"falling back to tabledata.list API.")
rows_iter = client.list_rows(
self._query_job.destination,
selected_fields=self._query_job._query_results.schema,
page_size=self.arraysize,
)
self._query_data = iter(rows_iter)
def _try_fetch(self, size=None):
"""Try to start fetching data, if not yet started.
Mutates self to indicate that iteration has started.
"""
if self._query_job is None:
raise exceptions.InterfaceError(
"No query results: execute() must be called before fetch.")
if self._query_job.dry_run:
self._query_data = iter([])
return
if self._query_data is None:
bqstorage_client = self.connection._bqstorage_client
if bqstorage_client is not None:
rows_iterable = self._bqstorage_fetch(bqstorage_client)
self._query_data = _helpers.to_bq_table_rows(rows_iterable)
return
rows_iter = self._query_job.result(page_size=self.arraysize)
self._query_data = iter(rows_iter)