django-pyodbc-azure rollback error with previously working configuration - line 389

Question

I've been using django-pyodbc-azure for a while on Linux, along with pydobc, FreeTDS and unixODBC to connect Django to SQL Server 2014. I ran into this problem with an application that had been working fine, and am having trouble debugging it. To reproduce the problem, I started a brand new Django app to keep things simple. Here's my virtualenv:

(azuretest)[vagrant@vagrant azuretest]$ pip freeze
Django==1.8.6
django-pyodbc-azure==1.8.3.0
pyodbc==3.0.10

Here's my database config to connect to SQL Server:

DATABASES = {
    'default': {
        'ENGINE': 'sql_server.pyodbc',
        'HOST': 'myserver.com',
        'PORT': '1433',
        'NAME': 'my_db',
        'USER': 'my_db_user',
        'PASSWORD': 'mypw',
        'AUTOCOMMIT': True,
        'OPTIONS': {
            'driver': 'FreeTDS',
            'autocommit': True,
            'unicode_results': True,
            'host_is_server': True,
            'extra_params': 'tds_version=7.2',
        },
    },
}

And I created a simple models.py:

class TestTemp(models.Model):
    tempdate = models.DateField()

This set up has been working fine in a fairly complex Django project, which can still SELECT to this same database. However, whenever I try to do an UPDATE or migration, I've been getting this error:

(azuretest)[vagrant@vagrant azuretest]$ ./manage.py migrate home
Operations to perform:
  Apply all migrations: home
Running migrations:
  Rendering model states... DONE
  Applying home.0001_initial...Traceback (most recent call last):
  File "/home/vagrant/.virtualenvs/azuretest/lib/python3.4/site-packages/sql_server/pyodbc/base.py", line 389, in _set_aut
ocommit
    self.connection.rollback()
pyodbc.Error: ('HY000', 'The driver did not supply an error!')

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "./manage.py", line 10, in <module>
    execute_from_command_line(sys.argv)
  File "/home/vagrant/.virtualenvs/azuretest/lib/python3.4/site-packages/django/core/management/__init__.py", line 354, in
 execute_from_command_line
    utility.execute()
  File "/home/vagrant/.virtualenvs/azuretest/lib/python3.4/site-packages/django/core/management/__init__.py", line 346, in
 execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/home/vagrant/.virtualenvs/azuretest/lib/python3.4/site-packages/django/core/management/base.py", line 394, in run
_from_argv
    self.execute(*args, **cmd_options)
  File "/home/vagrant/.virtualenvs/azuretest/lib/python3.4/site-packages/django/core/management/base.py", line 445, in exe
cute
    output = self.handle(*args, **options)
  File "/home/vagrant/.virtualenvs/azuretest/lib/python3.4/site-packages/django/core/management/commands/migrate.py", line
 222, in handle
    executor.migrate(targets, plan, fake=fake, fake_initial=fake_initial)
  File "/home/vagrant/.virtualenvs/azuretest/lib/python3.4/site-packages/django/db/migrations/executor.py", line 110, in m
igrate
    self.apply_migration(states[migration], migration, fake=fake, fake_initial=fake_initial)
  File "/home/vagrant/.virtualenvs/azuretest/lib/python3.4/site-packages/django/db/migrations/executor.py", line 154, in a
pply_migration
    self.recorder.record_applied(migration.app_label, migration.name)
  File "/home/vagrant/.virtualenvs/azuretest/lib/python3.4/site-packages/django/db/migrations/recorder.py", line 67, in re
cord_applied
    self.migration_qs.create(app=app, name=name)
  File "/home/vagrant/.virtualenvs/azuretest/lib/python3.4/site-packages/django/db/models/query.py", line 348, in create
    obj.save(force_insert=True, using=self.db)
  File "/home/vagrant/.virtualenvs/azuretest/lib/python3.4/site-packages/django/db/models/base.py", line 734, in save
    force_update=force_update, update_fields=update_fields)
  File "/home/vagrant/.virtualenvs/azuretest/lib/python3.4/site-packages/django/db/models/base.py", line 759, in save_base

    with transaction.atomic(using=using, savepoint=False):
  File "/home/vagrant/.virtualenvs/azuretest/lib/python3.4/site-packages/django/db/transaction.py", line 186, in __enter__

    connection.set_autocommit(False)
  File "/home/vagrant/.virtualenvs/azuretest/lib/python3.4/site-packages/django/db/backends/base/base.py", line 295, in se
t_autocommit
    self._set_autocommit(autocommit)
  File "/home/vagrant/.virtualenvs/azuretest/lib/python3.4/site-packages/sql_server/pyodbc/base.py", line 390, in _set_aut
ocommit
    self.connection.autocommit = autocommit
  File "/home/vagrant/.virtualenvs/azuretest/lib/python3.4/site-packages/django/db/utils.py", line 98, in __exit__
    six.reraise(dj_exc_type, dj_exc_value, traceback)
  File "/home/vagrant/.virtualenvs/azuretest/lib/python3.4/site-packages/django/utils/six.py", line 658, in reraise
    raise value.with_traceback(tb)
  File "/home/vagrant/.virtualenvs/azuretest/lib/python3.4/site-packages/sql_server/pyodbc/base.py", line 389, in _set_aut
ocommit
    self.connection.rollback()
django.db.utils.Error: ('HY000', 'The driver did not supply an error!')

The weird part is that it successfully creates the table in SQL Server ([home_testtemp]), and seems to be erroring out on an un-necessary rollback. Any ideas on best ways to debug this further or fix the issue? When I run the SQL output by ./manage.py sqlmigrate home directly against the database logged in with this username and password, it works fine.

Thanks in advance.

UPDATE 1: this isn't a good fix, but gets around what appears to be a problem with a rollback being called when it shouldn't. This change is made around line 389 of base.py in django-pyodbc-azure:

This is ugly and gets rid of a safeguard, but makes things work in the meantime. Modifying base.py around line 389 in django-pyodbc-azure:

def _set_autocommit(self, autocommit):
        self.connection.commit()

#        with self.wrap_database_errors:
#            if autocommit:
#                self.connection.commit()
#            else:
#                self.connection.rollback()
#            self.connection.autocommit = autocommit

Obviously, still looking for an actual fix rather than a hack and the root cause.

UPDATE 2: Back out the change made in UPDATE 1 above to the original django-pyodbc. Then in the SETTINGS, change the tds_version to be either 7.0 or 7.1. It works. If you change it to 7.2 or 7.3, it breaks. Could this be a problem with the new DATE fields available starting in SQL Server 2008? Either way, a temp solution is to revert to TDS Version 7.1, and this is clearly useful information towards a fix.

Answer 1

A new version of django-pyodbc-azure has been published which fixes this issue for me (thank you, Michaya). To fix it, simply upgrade:

pip install django-pyodbc-azure==1.8.6

...and update your requirements files wherever necessary. Details here: https://github.com/michiya/django-pyodbc-azure/issues/46

Answer 2

Because it works on 7.0 and 7.1, I wonder if your SQL Server 2014 database is set to the SQL Server 2000 compatibility level which would restrict you to use TDS version 7.1 or lower.

Links:

TDS Versions

Product Behavior