Filtering wrong using a timestamp range in django views

Question

When I want to filter my model using one exactly date I use the following code line,

today = datetime.datetime.now().date()
today_data = DevData.objects.filter(data_timestamp__date=today)

And when I want to filter using a range of days, I use the following code line,

last7days = datetime.datetime.now().date() - datetime.timedelta(days=7)
last7days_data = DevData.objects.filter(data_timestamp__range=(last7days,today))

The problem is that when I use this second code, appears a warning and runs very very slow,

RuntimeWarning: DateTimeField DevData.data_timestamp received a naive datetime (2020-05-31 00:00:00) while time zone support is active.

How can I do it better?

I found this post, but don't understand how to solve it. Can somebody help me please?

score 0 · Answer 1 · answered May 31 '20 at 17:02

The fact that it runs rather slow is likely because you did not set a database index on the data_timestamp field, you can add one by specifying a db_index=True parameter [Django-doc]:

class DevData(models.Data):
    data_timestamp = models.DateTimeField(db_index=True)
    # …

You can furthermore filter the data by adding a __date lookup [Django-doc] in the query:

last7days = datetime.datetime.now().date() - datetime.timedelta(days=7)
last7days_data = DevData.objects.filter(
    data_timestamp__date__range=(last7days,today)
)

score 0 · Answer 2 · answered May 31 '20 at 17:06

You are seeing a warning because last7days variable is not timezone-aware.

You can make it timezone-aware like so:

import datetime
from datetime import timezone

unaware = datetime.datetime(2020, 1, 1, 1, 1, 1, 1)
aware = unaware.replace(tzinfo=timezone.utc))

Filtering wrong using a timestamp range in django views

2 Answers2