#34464: QuerySet.count() regression on Django 4.2 with values() and annotate()
-------------------------------------+-------------------------------------
Reporter: Ian | Owner: nobody
Type: Bug | Status: new
Component: Database | Version: 4.2
layer (models, ORM) |
Severity: Normal | Keywords: postgresql
Triage Stage: | Has patch: 0
Unreviewed |
Needs documentation: 0 | Needs tests: 0
Patch needs improvement: 0 | Easy pickings: 0
UI/UX: 0 |
-------------------------------------+-------------------------------------
After upgrading to Django 4.2 we noticed incorrect results on some queries
we use in reporting.
We are using PostgreSQL as our database.
Using psycopg2 or the new psycopg 3 support does not change the result.
Sample model:
{{{
#!python
class SampleModel(models.Model):
sample_datetime_field = models.DateTimeField()
}}}
Example code to reproduce the issue:
{{{
#!python
from bug_test.models import SampleModel
from django.db.models import Count
from django.db.models.functions import TruncHour
from django.utils import timezone
# Prepopulate 10 hours of sample data
now = timezone.now()
for i in range(10):
field_value = now - timedelta(hours=1 + i)
for i in range(5):
SampleModel.objects.create(sample_datetime_field=field_value)
# Affected query example
qs =
SampleModel.objects.all().annotate(hour=TruncHour('sample_datetime_field')).\
values('hour').annotate(hour_count=Count('*')).filter(hour_count__gte=5)
print(f"Count: {qs.count()}") # Incorrectly returns 0. Returns correct
result on Django 4.1
print(f"Len: {len(qs)}") # Returns correct result of 10
}}}
--
Ticket URL: <https://code.djangoproject.com/ticket/34464>
Django <https://code.djangoproject.com/>
The Web framework for perfectionists with deadlines.
--
You received this message because you are subscribed to the Google Groups
"Django updates" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
To view this discussion on the web visit
https://groups.google.com/d/msgid/django-updates/01070187557a565a-d16028a8-2a67-48a8-90d8-22775287db52-000000%40eu-central-1.amazonses.com.
