#16773: QuerySet.count does no caching until the result cache is filled
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Reporter: eternicode | Owner: nobody
Type: Bug | Status: new
Milestone: | Component: Database layer (models, ORM)
Version: 1.3 | Severity: Normal
Keywords: | Triage Stage: Unreviewed
Has patch: 0 | Easy pickings: 0
UI/UX: 0 |
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Before a queryset is evaluated, each QuerySet.count call for a given
QuerySet hits the database with a `COUNT(*)` query, and doesn't cache the
result in any way.
{{{
In [1]: from django.contrib.auth.models import User
In [2]: from django.db import connections
In [3]: qs = User.objects.all()
In [4]: qs.count()
Out[4]: 3
In [5]: qs.count()
Out[5]: 3
In [6]: list(qs);
In [7]: qs.count()
Out[7]: 3
In [8]: connections['default'].queries
Out[8]:
[{'sql': 'SELECT COUNT(*) FROM "auth_user"', 'time': '0.005'},
{'sql': 'SELECT COUNT(*) FROM "auth_user"', 'time': '0.001'},
{'sql': 'SELECT "auth_user"."id", "auth_user"."username",
"auth_user"."first_name", "auth_user"."last_name", "auth_user"."email",
"auth_user"."password", "auth_user"."is_staff", "auth_user"."is_active",
"auth_user"."is_superuser", "auth_user"."last_login",
"auth_user"."date_joined" FROM "auth_user"',
'time': '0.001'}]
}}}
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Ticket URL: <https://code.djangoproject.com/ticket/16773>
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