Viewing file:  0002_new_column.py (1.04 KB) -rw-r--r--
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"""
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)),
),
]
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