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dfadbdac6a
SQLite doesn't work with more than 1000 parameters in a single query. The deletion code could generate queries that try to get related objects for more than 1000 objects thus breaking the limit. Django now splits the related object fetching into batches with at most 1000 parameters. The tests and patch include some work done by Trac alias NiGhTTraX in ticket #21205.
429 lines
15 KiB
Python
429 lines
15 KiB
Python
from __future__ import unicode_literals
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from math import ceil
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from django.db import models, IntegrityError, connection
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from django.db.models.sql.constants import GET_ITERATOR_CHUNK_SIZE
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from django.test import TestCase, skipUnlessDBFeature, skipIfDBFeature
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from django.utils.six.moves import xrange
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from .models import (R, RChild, S, T, A, M, MR, MRNull,
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create_a, get_default_r, User, Avatar, HiddenUser, HiddenUserProfile,
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M2MTo, M2MFrom, Parent, Child, Base)
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class OnDeleteTests(TestCase):
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def setUp(self):
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self.DEFAULT = get_default_r()
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def test_auto(self):
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a = create_a('auto')
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a.auto.delete()
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self.assertFalse(A.objects.filter(name='auto').exists())
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def test_auto_nullable(self):
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a = create_a('auto_nullable')
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a.auto_nullable.delete()
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self.assertFalse(A.objects.filter(name='auto_nullable').exists())
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def test_setvalue(self):
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a = create_a('setvalue')
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a.setvalue.delete()
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a = A.objects.get(pk=a.pk)
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self.assertEqual(self.DEFAULT, a.setvalue)
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def test_setnull(self):
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a = create_a('setnull')
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a.setnull.delete()
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a = A.objects.get(pk=a.pk)
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self.assertEqual(None, a.setnull)
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def test_setdefault(self):
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a = create_a('setdefault')
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a.setdefault.delete()
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a = A.objects.get(pk=a.pk)
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self.assertEqual(self.DEFAULT, a.setdefault)
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def test_setdefault_none(self):
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a = create_a('setdefault_none')
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a.setdefault_none.delete()
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a = A.objects.get(pk=a.pk)
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self.assertEqual(None, a.setdefault_none)
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def test_cascade(self):
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a = create_a('cascade')
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a.cascade.delete()
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self.assertFalse(A.objects.filter(name='cascade').exists())
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def test_cascade_nullable(self):
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a = create_a('cascade_nullable')
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a.cascade_nullable.delete()
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self.assertFalse(A.objects.filter(name='cascade_nullable').exists())
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def test_protect(self):
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a = create_a('protect')
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self.assertRaises(IntegrityError, a.protect.delete)
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def test_do_nothing(self):
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# Testing DO_NOTHING is a bit harder: It would raise IntegrityError for a normal model,
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# so we connect to pre_delete and set the fk to a known value.
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replacement_r = R.objects.create()
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def check_do_nothing(sender, **kwargs):
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obj = kwargs['instance']
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obj.donothing_set.update(donothing=replacement_r)
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models.signals.pre_delete.connect(check_do_nothing)
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a = create_a('do_nothing')
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a.donothing.delete()
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a = A.objects.get(pk=a.pk)
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self.assertEqual(replacement_r, a.donothing)
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models.signals.pre_delete.disconnect(check_do_nothing)
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def test_do_nothing_qscount(self):
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"""
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Test that a models.DO_NOTHING relation doesn't trigger a query.
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"""
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b = Base.objects.create()
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with self.assertNumQueries(1):
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# RelToBase should not be queried.
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b.delete()
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self.assertEqual(Base.objects.count(), 0)
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def test_inheritance_cascade_up(self):
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child = RChild.objects.create()
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child.delete()
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self.assertFalse(R.objects.filter(pk=child.pk).exists())
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def test_inheritance_cascade_down(self):
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child = RChild.objects.create()
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parent = child.r_ptr
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parent.delete()
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self.assertFalse(RChild.objects.filter(pk=child.pk).exists())
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def test_cascade_from_child(self):
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a = create_a('child')
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a.child.delete()
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self.assertFalse(A.objects.filter(name='child').exists())
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self.assertFalse(R.objects.filter(pk=a.child_id).exists())
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def test_cascade_from_parent(self):
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a = create_a('child')
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R.objects.get(pk=a.child_id).delete()
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self.assertFalse(A.objects.filter(name='child').exists())
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self.assertFalse(RChild.objects.filter(pk=a.child_id).exists())
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def test_setnull_from_child(self):
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a = create_a('child_setnull')
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a.child_setnull.delete()
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self.assertFalse(R.objects.filter(pk=a.child_setnull_id).exists())
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a = A.objects.get(pk=a.pk)
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self.assertEqual(None, a.child_setnull)
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def test_setnull_from_parent(self):
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a = create_a('child_setnull')
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R.objects.get(pk=a.child_setnull_id).delete()
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self.assertFalse(RChild.objects.filter(pk=a.child_setnull_id).exists())
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a = A.objects.get(pk=a.pk)
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self.assertEqual(None, a.child_setnull)
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def test_o2o_setnull(self):
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a = create_a('o2o_setnull')
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a.o2o_setnull.delete()
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a = A.objects.get(pk=a.pk)
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self.assertEqual(None, a.o2o_setnull)
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class DeletionTests(TestCase):
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def test_m2m(self):
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m = M.objects.create()
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r = R.objects.create()
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MR.objects.create(m=m, r=r)
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r.delete()
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self.assertFalse(MR.objects.exists())
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r = R.objects.create()
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MR.objects.create(m=m, r=r)
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m.delete()
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self.assertFalse(MR.objects.exists())
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m = M.objects.create()
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r = R.objects.create()
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m.m2m.add(r)
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r.delete()
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through = M._meta.get_field('m2m').rel.through
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self.assertFalse(through.objects.exists())
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r = R.objects.create()
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m.m2m.add(r)
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m.delete()
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self.assertFalse(through.objects.exists())
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m = M.objects.create()
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r = R.objects.create()
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MRNull.objects.create(m=m, r=r)
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r.delete()
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self.assertFalse(not MRNull.objects.exists())
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self.assertFalse(m.m2m_through_null.exists())
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def test_bulk(self):
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s = S.objects.create(r=R.objects.create())
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for i in xrange(2 * GET_ITERATOR_CHUNK_SIZE):
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T.objects.create(s=s)
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# 1 (select related `T` instances)
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# + 1 (select related `U` instances)
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# + 2 (delete `T` instances in batches)
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# + 1 (delete `s`)
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self.assertNumQueries(5, s.delete)
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self.assertFalse(S.objects.exists())
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def test_instance_update(self):
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deleted = []
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related_setnull_sets = []
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def pre_delete(sender, **kwargs):
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obj = kwargs['instance']
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deleted.append(obj)
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if isinstance(obj, R):
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related_setnull_sets.append(list(a.pk for a in obj.setnull_set.all()))
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models.signals.pre_delete.connect(pre_delete)
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a = create_a('update_setnull')
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a.setnull.delete()
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a = create_a('update_cascade')
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a.cascade.delete()
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for obj in deleted:
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self.assertEqual(None, obj.pk)
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for pk_list in related_setnull_sets:
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for a in A.objects.filter(id__in=pk_list):
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self.assertEqual(None, a.setnull)
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models.signals.pre_delete.disconnect(pre_delete)
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def test_deletion_order(self):
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pre_delete_order = []
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post_delete_order = []
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def log_post_delete(sender, **kwargs):
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pre_delete_order.append((sender, kwargs['instance'].pk))
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def log_pre_delete(sender, **kwargs):
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post_delete_order.append((sender, kwargs['instance'].pk))
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models.signals.post_delete.connect(log_post_delete)
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models.signals.pre_delete.connect(log_pre_delete)
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r = R.objects.create(pk=1)
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s1 = S.objects.create(pk=1, r=r)
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s2 = S.objects.create(pk=2, r=r)
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T.objects.create(pk=1, s=s1)
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T.objects.create(pk=2, s=s2)
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r.delete()
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self.assertEqual(
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pre_delete_order, [(T, 2), (T, 1), (S, 2), (S, 1), (R, 1)]
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)
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self.assertEqual(
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post_delete_order, [(T, 1), (T, 2), (S, 1), (S, 2), (R, 1)]
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)
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models.signals.post_delete.disconnect(log_post_delete)
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models.signals.pre_delete.disconnect(log_pre_delete)
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def test_relational_post_delete_signals_happen_before_parent_object(self):
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deletions = []
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def log_post_delete(instance, **kwargs):
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self.assertTrue(R.objects.filter(pk=instance.r_id))
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self.assertIs(type(instance), S)
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deletions.append(instance.id)
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r = R.objects.create(pk=1)
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S.objects.create(pk=1, r=r)
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models.signals.post_delete.connect(log_post_delete, sender=S)
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try:
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r.delete()
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finally:
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models.signals.post_delete.disconnect(log_post_delete)
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self.assertEqual(len(deletions), 1)
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self.assertEqual(deletions[0], 1)
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@skipUnlessDBFeature("can_defer_constraint_checks")
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def test_can_defer_constraint_checks(self):
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u = User.objects.create(
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avatar=Avatar.objects.create()
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)
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a = Avatar.objects.get(pk=u.avatar_id)
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# 1 query to find the users for the avatar.
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# 1 query to delete the user
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# 1 query to delete the avatar
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# The important thing is that when we can defer constraint checks there
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# is no need to do an UPDATE on User.avatar to null it out.
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# Attach a signal to make sure we will not do fast_deletes.
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calls = []
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def noop(*args, **kwargs):
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calls.append('')
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models.signals.post_delete.connect(noop, sender=User)
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self.assertNumQueries(3, a.delete)
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self.assertFalse(User.objects.exists())
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self.assertFalse(Avatar.objects.exists())
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self.assertEqual(len(calls), 1)
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models.signals.post_delete.disconnect(noop, sender=User)
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@skipIfDBFeature("can_defer_constraint_checks")
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def test_cannot_defer_constraint_checks(self):
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u = User.objects.create(
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avatar=Avatar.objects.create()
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)
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# Attach a signal to make sure we will not do fast_deletes.
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calls = []
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def noop(*args, **kwargs):
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calls.append('')
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models.signals.post_delete.connect(noop, sender=User)
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a = Avatar.objects.get(pk=u.avatar_id)
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# The below doesn't make sense... Why do we need to null out
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# user.avatar if we are going to delete the user immediately after it,
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# and there are no more cascades.
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# 1 query to find the users for the avatar.
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# 1 query to delete the user
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# 1 query to null out user.avatar, because we can't defer the constraint
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# 1 query to delete the avatar
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self.assertNumQueries(4, a.delete)
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self.assertFalse(User.objects.exists())
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self.assertFalse(Avatar.objects.exists())
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self.assertEqual(len(calls), 1)
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models.signals.post_delete.disconnect(noop, sender=User)
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def test_hidden_related(self):
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r = R.objects.create()
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h = HiddenUser.objects.create(r=r)
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HiddenUserProfile.objects.create(user=h)
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r.delete()
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self.assertEqual(HiddenUserProfile.objects.count(), 0)
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def test_large_delete(self):
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TEST_SIZE = 2000
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objs = [Avatar() for i in range(0, TEST_SIZE)]
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Avatar.objects.bulk_create(objs)
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# Calculate the number of queries needed.
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batch_size = connection.ops.bulk_batch_size(['pk'], objs)
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# The related fetches are done in batches.
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batches = int(ceil(float(len(objs)) / batch_size))
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# One query for Avatar.objects.all() and then one related fast delete for
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# each batch.
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fetches_to_mem = 1 + batches
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# The Avatar objecs are going to be deleted in batches of GET_ITERATOR_CHUNK_SIZE
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queries = fetches_to_mem + TEST_SIZE // GET_ITERATOR_CHUNK_SIZE
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self.assertNumQueries(queries, Avatar.objects.all().delete)
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self.assertFalse(Avatar.objects.exists())
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def test_large_delete_related(self):
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TEST_SIZE = 2000
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s = S.objects.create(r=R.objects.create())
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for i in xrange(TEST_SIZE):
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T.objects.create(s=s)
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batch_size = max(connection.ops.bulk_batch_size(['pk'], xrange(TEST_SIZE)), 1)
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# TEST_SIZE // batch_size (select related `T` instances)
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# + 1 (select related `U` instances)
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# + TEST_SIZE // GET_ITERATOR_CHUNK_SIZE (delete `T` instances in batches)
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# + 1 (delete `s`)
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expected_num_queries = (ceil(TEST_SIZE // batch_size) +
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ceil(TEST_SIZE // GET_ITERATOR_CHUNK_SIZE) + 2)
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self.assertNumQueries(expected_num_queries, s.delete)
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self.assertFalse(S.objects.exists())
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self.assertFalse(T.objects.exists())
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class FastDeleteTests(TestCase):
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def test_fast_delete_fk(self):
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u = User.objects.create(
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avatar=Avatar.objects.create()
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)
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a = Avatar.objects.get(pk=u.avatar_id)
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# 1 query to fast-delete the user
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# 1 query to delete the avatar
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self.assertNumQueries(2, a.delete)
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self.assertFalse(User.objects.exists())
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self.assertFalse(Avatar.objects.exists())
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def test_fast_delete_m2m(self):
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t = M2MTo.objects.create()
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f = M2MFrom.objects.create()
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f.m2m.add(t)
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# 1 to delete f, 1 to fast-delete m2m for f
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self.assertNumQueries(2, f.delete)
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def test_fast_delete_revm2m(self):
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t = M2MTo.objects.create()
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f = M2MFrom.objects.create()
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f.m2m.add(t)
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# 1 to delete t, 1 to fast-delete t's m_set
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self.assertNumQueries(2, f.delete)
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def test_fast_delete_qs(self):
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u1 = User.objects.create()
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u2 = User.objects.create()
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self.assertNumQueries(1, User.objects.filter(pk=u1.pk).delete)
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self.assertEqual(User.objects.count(), 1)
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self.assertTrue(User.objects.filter(pk=u2.pk).exists())
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def test_fast_delete_joined_qs(self):
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a = Avatar.objects.create(desc='a')
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User.objects.create(avatar=a)
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u2 = User.objects.create()
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expected_queries = 1 if connection.features.update_can_self_select else 2
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self.assertNumQueries(expected_queries,
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User.objects.filter(avatar__desc='a').delete)
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self.assertEqual(User.objects.count(), 1)
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self.assertTrue(User.objects.filter(pk=u2.pk).exists())
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def test_fast_delete_inheritance(self):
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c = Child.objects.create()
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p = Parent.objects.create()
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# 1 for self, 1 for parent
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# However, this doesn't work as child.parent access creates a query,
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# and this means we will be generating extra queries (a lot for large
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# querysets). This is not a fast-delete problem.
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# self.assertNumQueries(2, c.delete)
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c.delete()
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self.assertFalse(Child.objects.exists())
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self.assertEqual(Parent.objects.count(), 1)
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self.assertEqual(Parent.objects.filter(pk=p.pk).count(), 1)
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# 1 for self delete, 1 for fast delete of empty "child" qs.
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self.assertNumQueries(2, p.delete)
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self.assertFalse(Parent.objects.exists())
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# 1 for self delete, 1 for fast delete of empty "child" qs.
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c = Child.objects.create()
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p = c.parent_ptr
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self.assertNumQueries(2, p.delete)
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self.assertFalse(Parent.objects.exists())
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self.assertFalse(Child.objects.exists())
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def test_fast_delete_large_batch(self):
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User.objects.bulk_create(User() for i in range(0, 2000))
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# No problems here - we aren't going to cascade, so we will fast
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# delete the objects in a single query.
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self.assertNumQueries(1, User.objects.all().delete)
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a = Avatar.objects.create(desc='a')
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User.objects.bulk_create(User(avatar=a) for i in range(0, 2000))
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# We don't hit parameter amount limits for a, so just one query for
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# that + fast delete of the related objs.
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self.assertNumQueries(2, a.delete)
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self.assertEqual(User.objects.count(), 0)
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