snowflake-connector-python: SNOW-242177: AttributeError: 'NoneType' object has no attribute 'fetch'

Please answer these questions before submitting your issue. Thanks!

What version of Python are you using (python --version)?

Python3.8.2

What operating system and processor architecture are you using (python -c 'import platform; print(platform.platform())')?

Using python:3.8.2 image from DockerHub

What are the component versions in the environment (pip freeze)?

snowflake-connector-python==2.1.1
azure-storage-blob==2.1.0
jinja2==2.11.2

What did you do?

    results = execute_snowflake_query(snowflake_database, None, query, context, verbose)
    existing_privileges = []
    for cursor in results:
        cursor_results = cursor.fetchmany(1000000)
        cursor_results_array = list(itertools.chain.from_iterable(cursor_results))
        print(cursor_results_array[0])
        if cursor_results_array[0] != 'Statement executed successfully.':
            existing_privileges.extend(cursor_results_array)
    return existing_privileges

What did you expect to see?

No error

What did you see instead?

AttributeError: 'NoneType' object has no attribute 'fetch'

Can you set logging to DEBUG and collect the logs?

Statement executed successfully.
--
  | Traceback (most recent call last):
  | File "/usr/local/lib/python3.8/site-packages/snowflake/connector/json_result.py", line 76, in __next__
  | row = next(self._current_chunk_row)
  | File "/usr/local/lib/python3.8/site-packages/snowflake/connector/chunk_downloader.py", line 270, in __next__
  | return next(self._it)
  | StopIteration
  |  
  | During handling of the above exception, another exception occurred:
  |  
  | Traceback (most recent call last):
.... (not showing these as they are my code)
  | cursor_results = cursor.fetchmany(1000000)
  | File "/usr/local/lib/python3.8/site-packages/snowflake/connector/cursor.py", line 844, in fetchmany
  | row = self.fetchone()
  | File "/usr/local/lib/python3.8/site-packages/snowflake/connector/cursor.py", line 823, in fetchone
  | return next(self._result)
  | File "/usr/local/lib/python3.8/site-packages/snowflake/connector/json_result.py", line 82, in __next__
  | next_chunk = self._chunk_downloader.next_chunk()
  | File "/usr/local/lib/python3.8/site-packages/snowflake/connector/chunk_downloader.py", line 187, in next_chunk
  | raise self._downloader_error
  | File "/usr/local/lib/python3.8/site-packages/snowflake/connector/chunk_downloader.py", line 125, in _download_chunk
  | result_data = self._fetch_chunk(self._chunks[idx].url, headers)
  | File "/usr/local/lib/python3.8/site-packages/snowflake/connector/chunk_downloader.py", line 254, in _fetch_chunk
  | return self._connection.rest.fetch(
  | AttributeError: 'NoneType' object has no attribute 'fetch'

About this issue

Original URL
State: closed
Created 4 years ago
Reactions: 7
Comments: 22 (7 by maintainers)

Most upvoted comments

@gcnuss , Yes, that is the exact root cause that I found when I was troubleshooting. I think issue was resolved from snowflake-connector-python version 2.7.5.

kumar-sf on Jun 14, 2022

@sfc-gh-jbahk

def execute_snowflake_query(database, schema, query, context, verbose):
    con = snowflake.connector.connect(
        user = context['user'],
        account = context['account'],
        role = context['role'],
        warehouse = context['warehouse'],
        database = database,
        schema = schema,
        region = context['region'],
        authenticator = context['authenticator'],
        password = context['password']
    )
    if verbose:
        print("SQL query: %s" % query)
    try:
        return con.execute_string(query)
    finally:
        con.close()

krutisfood on Dec 16, 2021