MSSQL Error: list index out of range

[Habeeb556]

Bug description

I received the following error message:

list index out of range

This occurred when upgrading from version 2.1.3, which supports Python 3.8, to Superset version 4.0.2, which supports Python 3.11, using the MSSQL engine with pyodbc version 5.0.1.

How to reproduce the bug

I think the problem lies with the pyodbc version, as it works fine when using pymssql. However, all databases are currently configured with pyodbc. Do you have any recommendations to work around this issue?

Screenshots/recordings

Superset version

4.0.1

Python version

3.11

Node version

I don't know

Browser

Chrome

Additional context

No response

Checklist

• I have searched Superset docs and Slack and didn't find a solution to my problem.
• I have searched the GitHub issue tracker and didn't find a similar bug report.
• I have checked Superset's logs for errors and if I found a relevant Python stacktrace, I included it here as text in the "additional context" section.

[dosubot]

To work around the list index out of range issue when upgrading from Superset version 2.1.3 to version 4.0.2 while using the MSSQL engine with pyodbc version 5.0.1, you can modify the fetch_data method in the MssqlEngineSpec class to handle the unpacking of pyodbc.Row objects correctly.

Here is the relevant code snippet with the necessary modification:

@classmethod
def fetch_data(
    cls, cursor: Any, limit: Optional[int] = None
) -> list[tuple[Any, ...]]:
    if not cursor.description:
        return []
    data = super().fetch_data(cursor, limit)
    # Lists of `pyodbc.Row` need to be unpacked further
    return cls.pyodbc_rows_to_tuples(data)

Ensure that the pyodbc_rows_to_tuples method is correctly implemented to handle the conversion of pyodbc.Row objects to tuples. This should help in resolving the list index out of range issue ^[1].

To continue talking to Dosu, mention @dosu.

[Habeeb556]

@dosu I am sure that pyodbc_rows_to_tuples method is correctly implemented and still get the list index out of range issue.

[dosubot]

If the pyodbc_rows_to_tuples method is correctly implemented and you are still encountering the list index out of range issue, it might be due to changes in the data structure or the way data is fetched in the newer version of Superset. Here are a few additional steps you can take to diagnose and potentially resolve the issue:

1. Double-Check the Implementation:
   Ensure that the pyodbc_rows_to_tuples method is implemented as follows:

   @classmethod
   def pyodbc_rows_to_tuples(cls, data: list) -> list[tuple]:
       return [tuple(row) for row in data]

2. Review the fetch_data Method:
   Verify that the fetch_data method in the MssqlEngineSpec class is correctly calling pyodbc_rows_to_tuples:

   @classmethod
   def fetch_data(
       cls, cursor: Any, limit: Optional[int] = None
   ) -> list[tuple[Any, ...]]:
       if not cursor.description:
           return []
       data = super().fetch_data(cursor, limit)
       return cls.pyodbc_rows_to_tuples(data)

3. Check for Breaking Changes:
   Review the release notes for Superset versions between 2.1.3 and 4.0.2 for any breaking changes that might affect the MSSQL engine or the fetch_data method. Specifically, the following fix is relevant:

   • #27577 fix: sqlglot SQL Server (@betodealmeida) ^[1].

4. Add Logging for Debugging:
   Add logging to the fetch_data method to capture more details about the data being processed. This can help identify where the list index out of range error is occurring:

   import logging
   logger = logging.getLogger(__name__)
   
   @classmethod
   def fetch_data(
       cls, cursor: Any, limit: Optional[int] = None
   ) -> list[tuple[Any, ...]]:
       if not cursor.description:
           return []
       data = super().fetch_data(cursor, limit)
       logger.debug("Fetched data: %s", data)
       converted_data = cls.pyodbc_rows_to_tuples(data)
       logger.debug("Converted data: %s", converted_data)
       return converted_data

5. Review Unit Tests:
   Ensure that the unit tests for the fetch_data method are passing and cover the scenarios you are encountering. The test_fetch_data method in the tests/unit_tests/db_engine_specs/test_mssql.py file can provide insights into how the method is expected to behave ^[2].

By following these steps, you should be able to gather more information about the root cause of the list index out of range error and identify potential solutions.

To continue talking to Dosu, mention @dosu.

[Habeeb556]

++ Traceback @dosu

Traceback (most recent call last):
 File "/swloc/.virtualenvs/supersetvenv4/lib/python3.11/site-packages/flask/app.py", line 1484, in full_dispatch_request
   rv = self.dispatch_request()
        ^^^^^^^^^^^^^^^^^^^^^^^
 File "/swloc/.virtualenvs/supersetvenv4/lib/python3.11/site-packages/flask/app.py", line 1469, in dispatch_request
   return self.ensure_sync(self.view_functions[rule.endpoint])(**view_args)
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 File "/swloc/.virtualenvs/supersetvenv4/lib/python3.11/site-packages/flask_appbuilder/security/decorators.py", line 95, in wraps
   return f(self, *args, **kwargs)
          ^^^^^^^^^^^^^^^^^^^^^^^^
 File "/swloc/.virtualenvs/supersetvenv4/lib/python3.11/site-packages/superset/views/base_api.py", line 127, in wraps
   raise ex
 File "/swloc/.virtualenvs/supersetvenv4/lib/python3.11/site-packages/superset/views/base_api.py", line 121, in wraps
   duration, response = time_function(f, self, *args, **kwargs)
                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 File "/swloc/.virtualenvs/supersetvenv4/lib/python3.11/site-packages/superset/utils/core.py", line 1470, in time_function
   response = func(*args, **kwargs)
              ^^^^^^^^^^^^^^^^^^^^^
 File "/swloc/.virtualenvs/supersetvenv4/lib/python3.11/site-packages/superset/views/base_api.py", line 93, in wraps
   return f(self, *args, **kwargs)
          ^^^^^^^^^^^^^^^^^^^^^^^^
 File "/swloc/.virtualenvs/supersetvenv4/lib/python3.11/site-packages/superset/utils/log.py", line 255, in wrapper
   value = f(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^
 File "/swloc/.virtualenvs/supersetvenv4/lib/python3.11/site-packages/superset/sqllab/api.py", line 409, in execute_sql_query
   command_result: CommandResult = command.run()
                                   ^^^^^^^^^^^^^
 File "/swloc/.virtualenvs/supersetvenv4/lib/python3.11/site-packages/superset/commands/sql_lab/execute.py", line 121, in run
   raise ex
 File "/swloc/.virtualenvs/supersetvenv4/lib/python3.11/site-packages/superset/commands/sql_lab/execute.py", line 103, in run
   status = self._run_sql_json_exec_from_scratch()
            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 File "/swloc/.virtualenvs/supersetvenv4/lib/python3.11/site-packages/superset/commands/sql_lab/execute.py", line 163, in _run_sql_json_exec_from_scratch
   raise ex
 File "/swloc/.virtualenvs/supersetvenv4/lib/python3.11/site-packages/superset/commands/sql_lab/execute.py", line 158, in _run_sql_json_exec_from_scratch
   return self._sql_json_executor.execute(
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 File "/swloc/.virtualenvs/supersetvenv4/lib/python3.11/site-packages/superset/sqllab/sql_json_executer.py", line 111, in execute
   raise SupersetErrorsException(
superset.exceptions.SupersetErrorsException: [SupersetError(message='list index out of range', error_type=<SupersetErrorType.GENERIC_DB_ENGINE_ERROR: 'GENERIC_DB_ENGINE_ERROR'>, level=<ErrorLevel.ERROR: 'error'>, extra={'engine_name': 'Microsoft SQL Server', 'issue_codes': [{'code': 1002, 'message': 'Issue 1002 - The database returned an unexpected error.'}]})]

[dosubot]

The traceback indicates that the list index out of range error is being raised within the execute method of the SynchronousSqlJsonExecutor class in superset/sqllab/sql_json_executer.py. This method is part of the new SQL query execution logic introduced between Superset versions 2.1.3 and 4.0.2.

Given the traceback, here are some steps to further diagnose and resolve the issue:

1. Review the execute Method:
   Ensure that the execute method in the SynchronousSqlJsonExecutor class is correctly handling the data fetched from the database. Add logging to capture the state of the data at various points in the method.

   import logging
   logger = logging.getLogger(__name__)
   
   class SynchronousSqlJsonExecutor:
       # Existing attributes and methods
   
       def execute(self, execution_context: SqlJsonExecutionContext, rendered_query: str, log_params: dict[str, Any] | None) -> SqlJsonExecutionStatus:
           try:
               # Add logging before and after fetching data
               logger.debug("Executing query: %s", rendered_query)
               data = self._fetch_data(execution_context, rendered_query)
               logger.debug("Fetched data: %s", data)
               # Process data
               # ...
           except Exception as ex:
               logger.error("Error executing query: %s", ex)
               raise

2. Check Data Fetching Logic:
   Verify that the _fetch_data method (or equivalent) in the SynchronousSqlJsonExecutor class is correctly fetching and processing the data. Ensure that it handles pyodbc.Row objects properly.

3. Review Changes in superset/commands/sql_lab/execute.py:
   Examine the changes in the superset/commands/sql_lab/execute.py file between versions 2.1.3 and 4.0.2 to identify any modifications that could affect data fetching and processing.

4. Unit Tests:
   Ensure that unit tests for the SynchronousSqlJsonExecutor class and related methods are passing and cover the scenarios you are encountering. This can help identify any discrepancies in the expected behavior.

By following these steps, you should be able to gather more information about the root cause of the list index out of range error and identify potential solutions.

To continue talking to Dosu, mention @dosu.

[Habeeb556]

Okay, I found the error. It was a syntax mistake caused by a small detail in the copied source code. The old version of Python ignored it during execution, but the latest version doesn't, resulting in a list index out of range generic error.