microsoft / microsoft/mssql-python

bulkcopy fails for temporary tables

Open
#492 3 comments 0 reactions 1 assignee View on GitHub

@bewithgaurav is already working on this.

Since Apr 6, 2026.

area: bulk-copy enhancement inADO triage done
Dominant language
Python
Stars
472
Forks
60
Avg merge
2d 11h
Merged PRs (30d)
36

Description

bulkcopy fails when trying to populate a temporary table unless

  • the table is a ##global temporary table, and
  • autocommit is enabled
repro code
import mssql_python

cnxn = mssql_python.connect(
    "SERVER=192.168.0.199;"
    "DATABASE=test;"
    "UID=scott;PWD=tiger^5HHH;"
    "TrustServerCertificate=yes;"
)

# cnxn.setautocommit(True)
print(f"{cnxn.autocommit=}")

crsr = cnxn.cursor()

table_name = '#local_temp'
print(f"[{table_name=}]")

crsr.execute(f"CREATE TABLE {table_name} (id int, txt nvarchar(1))")

params = [(1, 'Ώ',), (2, 'π',), (3, 'α',)]
crsr.bulkcopy(table_name, params)
autocommit=False, #local temporary table
cnxn.autocommit=False
[table_name='#local_temp']
Traceback (most recent call last):
  File "C:\Users\gord\PycharmProjects\mssql_python_demo\gdt_demo.py", line 22, in <module>
    crsr.bulkcopy(table_name, params)
    ~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^
  File "C:\Users\gord\PycharmProjects\mssql_python_demo\.venv\Lib\site-packages\mssql_python\cursor.py", line 2706, in bulkcopy
    raise type(e)(str(e)) from None
RuntimeError: Failed to retrieve destination metadata: Sql Error: 208: Class 16: State 0: Invalid object name '#local_temp'. on 5ec209db8c16 in  at line 1
autocommit=False, ##global temporary table
cnxn.autocommit=False
[table_name='##global_temp']
Traceback (most recent call last):
  File "C:\Users\gord\PycharmProjects\mssql_python_demo\gdt_demo.py", line 22, in <module>
    crsr.bulkcopy(table_name, params)
    ~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^
  File "C:\Users\gord\PycharmProjects\mssql_python_demo\.venv\Lib\site-packages\mssql_python\cursor.py", line 2706, in bulkcopy
    raise type(e)(str(e)) from None
RuntimeError: Failed to retrieve destination metadata: Timeout Error: Elapsed: deadline has elapsed
autocommit=True, #local temporary table
cnxn.autocommit=True
[table_name='#local_temp']
Traceback (most recent call last):
  File "C:\Users\gord\PycharmProjects\mssql_python_demo\gdt_demo.py", line 22, in <module>
    crsr.bulkcopy(table_name, params)
    ~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^
  File "C:\Users\gord\PycharmProjects\mssql_python_demo\.venv\Lib\site-packages\mssql_python\cursor.py", line 2706, in bulkcopy
    raise type(e)(str(e)) from None
RuntimeError: Failed to retrieve destination metadata: Sql Error: 208: Class 16: State 0: Invalid object name '#local_temp'. on 5ec209db8c16 in  at line 1
autocommit=True, ##global temporary table

(works as expected)

additional info

I tried adding UseFMTONLY=Yes and ColumnEncryption=Enabled as suggested in

https://github.com/mkleehammer/pyodbc/wiki/Tips-and-Tricks-by-Database-Platform#---workaround-1-odbc-driver-17-for-sql-server-and-usefmtonlyyes-or-columnencryptionenabled

but they were rejected:

Traceback (most recent call last):
  File "C:\Users\gord\PycharmProjects\mssql_python_demo\gdt_demo.py", line 3, in <module>
    cnxn = mssql_python.connect(
        "SERVER=192.168.0.199;"
    ...<3 lines>...
        "ColumnEncryption=Enabled;"
    )
  File "C:\Users\gord\PycharmProjects\mssql_python_demo\.venv\Lib\site-packages\mssql_python\db_connection.py", line 46, in connect
    conn = Connection(
        connection_str, autocommit=autocommit, attrs_before=attrs_before, timeout=timeout, **kwargs
    )
  File "C:\Users\gord\PycharmProjects\mssql_python_demo\.venv\Lib\site-packages\mssql_python\connection.py", line 240, in __init__
    self.connection_str = self._construct_connection_string(connection_str, **kwargs)
                          ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Users\gord\PycharmProjects\mssql_python_demo\.venv\Lib\site-packages\mssql_python\connection.py", line 363, in _construct_connection_string
    parsed_params = parser._parse(connection_str)
  File "C:\Users\gord\PycharmProjects\mssql_python_demo\.venv\Lib\site-packages\mssql_python\connection_string_parser.py", line 271, in _parse
    raise ConnectionStringParseError(errors)
mssql_python.exceptions.ConnectionStringParseError: Connection string parsing failed:
  Unknown keyword 'columnencryption' is not recognized

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Assessment

This issue has not been assessed yet.

Get new issues in your inbox

A short digest of beginner-friendly GitHub issues.