Fixed #19102 -- Fixed fast-path delete for modified SELECT clause cases (f64a5ef4) · Commits · Dom Sekotill / django

django/db/models/sql/query.py

+13 −6

Original line number	Diff line number	Diff line
		@@ -431,13 +431,9 @@ class Query(object):

		def has_results(self, using):
		q = self.clone()
		q.clear_select_clause()
		q.add_extra({'a': 1}, None, None, None, None, None)
		q.select = []
		q.select_fields = []
		q.default_cols = False
		q.select_related = False
		q.set_extra_mask(('a',))
		q.set_aggregate_mask(())
		q.set_extra_mask(['a'])
		q.clear_ordering(True)
		q.set_limits(high=1)
		compiler = q.get_compiler(using=using)
		@@ -1626,6 +1622,17 @@ class Query(object):
		"""
		return not self.low_mark and self.high_mark is None

		def clear_select_clause(self):
		"""
		Removes all fields from SELECT clause.
		"""
		self.select = []
		self.select_fields = []
		self.default_cols = False
		self.select_related = False
		self.set_extra_mask(())
		self.set_aggregate_mask(())

		def clear_select_fields(self):
		"""
		Clears the list of fields to select (but not extra_select columns).

django/db/models/sql/subqueries.py

+3 −5

Original line number	Diff line number	Diff line
		@@ -70,8 +70,9 @@ class DeleteQuery(Query):
		self.delete_batch(values, using)
		return
		else:
		values = innerq
		innerq.clear_select_clause()
		innerq.select = [(self.get_initial_alias(), pk.column)]
		values = innerq
		where = self.where_class()
		where.add((Constraint(None, pk.column, pk), 'in', values), AND)
		self.where = where
		@@ -237,11 +238,8 @@ class DateQuery(Query):
		% field.name
		alias = result[3][-1]
		select = Date((alias, field.column), lookup_type)
		self.clear_select_clause()
		self.select = [select]
		self.select_fields = [None]
		self.select_related = False # See #7097.
		self.aggregates = SortedDict() # See 18056.
		self.set_extra_mask([])
		self.distinct = True
		self.order_by = order == 'ASC' and [1] or [-1]

tests/regressiontests/delete_regress/models.py

+7 −1

Original line number	Diff line number	Diff line
		@@ -2,7 +2,6 @@ from django.contrib.contenttypes import generic
		from django.contrib.contenttypes.models import ContentType
		from django.db import models


		class Award(models.Model):
		name = models.CharField(max_length=25)
		object_id = models.PositiveIntegerField()
		@@ -93,3 +92,10 @@ class FooPhoto(models.Model):
		class FooFileProxy(FooFile):
		class Meta:
		proxy = True

		class OrgUnit(models.Model):
		name = models.CharField(max_length=64, unique=True)

		class Login(models.Model):
		description = models.CharField(max_length=32)
		orgunit = models.ForeignKey(OrgUnit)

tests/regressiontests/delete_regress/tests.py

+85 −1

Original line number	Diff line number	Diff line
		@@ -8,7 +8,8 @@ from django.test import TestCase, TransactionTestCase, skipUnlessDBFeature

		from .models import (Book, Award, AwardNote, Person, Child, Toy, PlayedWith,
		PlayedWithNote, Email, Researcher, Food, Eaten, Policy, Version, Location,
		Item, Image, File, Photo, FooFile, FooImage, FooPhoto, FooFileProxy)
		Item, Image, File, Photo, FooFile, FooImage, FooPhoto, FooFileProxy, Login,
		OrgUnit)


		# Can't run this test under SQLite, because you can't
		@@ -265,3 +266,86 @@ class ProxyDeleteTest(TestCase):
		Image.objects.all().delete()

		self.assertEqual(len(FooFileProxy.objects.all()), 0)

		class Ticket19102Tests(TestCase):
		"""
		Test different queries which alter the SELECT clause of the query. We
		also must be using a subquery for the deletion (that is, the original
		query has a join in it). The deletion should be done as "fast-path"
		deletion (that is, just one query for the .delete() call).

		Note that .values() is not tested here on purpose. .values().delete()
		doesn't work for non fast-path deletes at all.
		"""
		def setUp(self):
		self.o1 = OrgUnit.objects.create(name='o1')
		self.o2 = OrgUnit.objects.create(name='o2')
		self.l1 = Login.objects.create(description='l1', orgunit=self.o1)
		self.l2 = Login.objects.create(description='l2', orgunit=self.o2)

		@skipUnlessDBFeature("update_can_self_select")
		def test_ticket_19102_annotate(self):
		with self.assertNumQueries(1):
		Login.objects.order_by('description').filter(
		orgunit__name__isnull=False
		).annotate(
		n=models.Count('description')
		).filter(
		n=1, pk=self.l1.pk
		).delete()
		self.assertFalse(Login.objects.filter(pk=self.l1.pk).exists())
		self.assertTrue(Login.objects.filter(pk=self.l2.pk).exists())

		@skipUnlessDBFeature("update_can_self_select")
		def test_ticket_19102_extra(self):
		with self.assertNumQueries(1):
		Login.objects.order_by('description').filter(
		orgunit__name__isnull=False
		).extra(
		select={'extraf':'1'}
		).filter(
		pk=self.l1.pk
		).delete()
		self.assertFalse(Login.objects.filter(pk=self.l1.pk).exists())
		self.assertTrue(Login.objects.filter(pk=self.l2.pk).exists())

		@skipUnlessDBFeature("update_can_self_select")
		@skipUnlessDBFeature('can_distinct_on_fields')
		def test_ticket_19102_distinct_on(self):
		# Both Login objs should have same description so that only the one
		# having smaller PK will be deleted.
		Login.objects.update(description='description')
		with self.assertNumQueries(1):
		Login.objects.distinct('description').order_by('pk').filter(
		orgunit__name__isnull=False
		).delete()
		# Assumed that l1 which is created first has smaller PK.
		self.assertFalse(Login.objects.filter(pk=self.l1.pk).exists())
		self.assertTrue(Login.objects.filter(pk=self.l2.pk).exists())

		@skipUnlessDBFeature("update_can_self_select")
		def test_ticket_19102_select_related(self):
		with self.assertNumQueries(1):
		Login.objects.filter(
		pk=self.l1.pk
		).filter(
		orgunit__name__isnull=False
		).order_by(
		'description'
		).select_related('orgunit').delete()
		self.assertFalse(Login.objects.filter(pk=self.l1.pk).exists())
		self.assertTrue(Login.objects.filter(pk=self.l2.pk).exists())

		@skipUnlessDBFeature("update_can_self_select")
		def test_ticket_19102_defer(self):
		with self.assertNumQueries(1):
		Login.objects.filter(
		pk=self.l1.pk
		).filter(
		orgunit__name__isnull=False
		).order_by(
		'description'
		).only('id').delete()
		self.assertFalse(Login.objects.filter(pk=self.l1.pk).exists())
		self.assertTrue(Login.objects.filter(pk=self.l2.pk).exists())