""" Migration file which adds a new column with a default value. This should trigger a warning because adding new columns with default value on a large table leads to DB performance issues. See: https://github.com/PyCQA/pylint-django/issues/118 and https://docs.djangoproject.com/en/2.0/topics/migrations/#postgresql > ... adding columns with default values will cause a full rewrite of > the table, for a time proportional to its size. > For this reason, it’s recommended you always create new columns with > null=True, as this way they will be added immediately. """ # pylint: disable=missing-docstring, invalid-name from datetime import timedelta from django.db import migrations, models class Migration(migrations.Migration): dependencies = [ ("input", "0001_noerror_initial"), ] operations = [ # add a timedelta field migrations.AddField( # [new-db-field-with-default] model_name="testrun", name="estimated_time", field=models.DurationField(default=timedelta(0)), ), ]