Show SQL if migration fails

[Thomas Güttler]

I would like to see the SQL of a migrations.RunSQL('...') command in a migration.

For me this is very important, because failures during migrations on prod systems can make serious trouble.

I want to see the SQL immediately.

Here is the current output. The SQL is missing even if you use "-v 3".

foo_eins_d@aptguettler:~$ manage.py migrate --traceback 
Operations to perform:
  Synchronize unmigrated apps: ...
  Apply all migrations: ...
Synchronizing apps without migrations:
  Creating tables...
    Running deferred SQL...
  Installing custom SQL...
Running migrations:
  Rendering model states... DONE
  Applying foo_eins.0002_auto_20160307_1559...Traceback (most recent call last):
  File "/home/foo_eins_d/src/djangotools/djangotools/bin/manage.py", line 29, in <module>
    main()
  File "/home/foo_eins_d/src/djangotools/djangotools/bin/manage.py", line 26, in main
    execute_from_command_line()
  File "/home/foo_eins_d/local/lib/python2.7/site-packages/django/core/management/__init__.py", line 354, in execute_from_command_line
    utility.execute()
  File "/home/foo_eins_d/local/lib/python2.7/site-packages/django/core/management/__init__.py", line 346, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/home/foo_eins_d/local/lib/python2.7/site-packages/django/core/management/base.py", line 394, in run_from_argv
    self.execute(*args, **cmd_options)
  File "/home/foo_eins_d/local/lib/python2.7/site-packages/django/core/management/base.py", line 445, in execute
    output = self.handle(*args, **options)
  File "/home/foo_eins_d/local/lib/python2.7/site-packages/django/core/management/commands/migrate.py", line 222, in handle
    executor.migrate(targets, plan, fake=fake, fake_initial=fake_initial)
  File "/home/foo_eins_d/local/lib/python2.7/site-packages/django/db/migrations/executor.py", line 110, in migrate
    self.apply_migration(states[migration], migration, fake=fake, fake_initial=fake_initial)
  File "/home/foo_eins_d/local/lib/python2.7/site-packages/django/db/migrations/executor.py", line 148, in apply_migration
    state = migration.apply(state, schema_editor)
  File "/home/foo_eins_d/local/lib/python2.7/site-packages/django/db/backends/base/schema.py", line 93, in __exit__
    self.atomic.__exit__(exc_type, exc_value, traceback)
  File "/home/foo_eins_d/local/lib/python2.7/site-packages/django/db/transaction.py", line 225, in __exit__
    connection.commit()
  File "/home/foo_eins_d/local/lib/python2.7/site-packages/django/db/backends/base/base.py", line 173, in commit
    self._commit()
  File "/home/foo_eins_d/local/lib/python2.7/site-packages/django/db/backends/base/base.py", line 142, in _commit
    return self.connection.commit()
  File "/home/foo_eins_d/local/lib/python2.7/site-packages/django/db/utils.py", line 98, in __exit__
    six.reraise(dj_exc_type, dj_exc_value, traceback)
  File "/home/foo_eins_d/local/lib/python2.7/site-packages/django/db/backends/base/base.py", line 142, in _commit
    return self.connection.commit()
django.db.utils.IntegrityError: update or delete on table "foo_table" violates foreign key constraint "foo_table_18a7d05da409f61d_fk_foo_table_id" on table "foo_other_table"
DETAIL:  Key (id)=(10002) is still referenced from table "foo_other_table".

What do you think?

[Tim Graham]

I'm not sure an implementation is feasible. A possible solution would be to configure your LOGGING setting to ​log all queries. Presumably you'd want a separate settings file from the one you use to run your server because logging all queries in that case probably wouldn't be desirable. Some databases can also log failing queries.

[Thomas Güttler]

My above problem is tricky: The exception does not happen during RunSQL(), it happens at the end during commit().

Django can not identify the migration operation which lead to the failure ...

[Tim Graham]

Right. Well, if you can provide a solution, feel free to do so.