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Fixed #9479 -- Corrected an edge case in bulk queryset deletion that …

…could cause an infinite loop when using MySQL InnoDB.

git-svn-id: http://code.djangoproject.com/svn/django/branches/soc2009/http-wsgi-improvements@10994 bcc190cf-cafb-0310-a4f2-bffc1f526a37
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commit cb847aa2249d10b14ec53e419f4610e4e7d08811 1 parent ae2dd58
@ccahoon ccahoon authored
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3  django/db/models/query.py
@@ -355,10 +355,11 @@ def delete(self):
# Delete objects in chunks to prevent the list of related objects from
# becoming too long.
+ seen_objs = None
while 1:
# Collect all the objects to be deleted in this chunk, and all the
# objects that are related to the objects that are to be deleted.
- seen_objs = CollectedObjects()
+ seen_objs = CollectedObjects(seen_objs)
for object in del_query[:CHUNK_SIZE]:
object._collect_sub_objects(seen_objs)
View
15 django/db/models/query_utils.py
@@ -32,11 +32,21 @@ class CollectedObjects(object):
This is used for the database object deletion routines so that we can
calculate the 'leaf' objects which should be deleted first.
+
+ previously_seen is an optional argument. It must be a CollectedObjects
+ instance itself; any previously_seen collected object will be blocked from
+ being added to this instance.
"""
- def __init__(self):
+ def __init__(self, previously_seen=None):
self.data = {}
self.children = {}
+ if previously_seen:
+ self.blocked = previously_seen.blocked
+ for cls, seen in previously_seen.data.items():
+ self.blocked.setdefault(cls, SortedDict()).update(seen)
+ else:
+ self.blocked = {}
def add(self, model, pk, obj, parent_model, nullable=False):
"""
@@ -53,6 +63,9 @@ def add(self, model, pk, obj, parent_model, nullable=False):
Returns True if the item already existed in the structure and
False otherwise.
"""
+ if pk in self.blocked.get(model, {}):
+ return True
+
d = self.data.setdefault(model, SortedDict())
retval = pk in d
d[pk] = obj
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1  tests/regressiontests/delete_regress/__init__.py
@@ -0,0 +1 @@
+
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61 tests/regressiontests/delete_regress/models.py
@@ -0,0 +1,61 @@
+from django.conf import settings
+from django.db import models, backend, connection, transaction
+from django.db.models import sql, query
+from django.test import TransactionTestCase
+
+class Book(models.Model):
+ pagecount = models.IntegerField()
+
+# Can't run this test under SQLite, because you can't
+# get two connections to an in-memory database.
+if settings.DATABASE_ENGINE != 'sqlite3':
+ class DeleteLockingTest(TransactionTestCase):
+ def setUp(self):
+ # Create a second connection to the database
+ self.conn2 = backend.DatabaseWrapper({
+ 'DATABASE_HOST': settings.DATABASE_HOST,
+ 'DATABASE_NAME': settings.DATABASE_NAME,
+ 'DATABASE_OPTIONS': settings.DATABASE_OPTIONS,
+ 'DATABASE_PASSWORD': settings.DATABASE_PASSWORD,
+ 'DATABASE_PORT': settings.DATABASE_PORT,
+ 'DATABASE_USER': settings.DATABASE_USER,
+ 'TIME_ZONE': settings.TIME_ZONE,
+ })
+
+ # Put both DB connections into managed transaction mode
+ transaction.enter_transaction_management()
+ transaction.managed(True)
+ self.conn2._enter_transaction_management(True)
+
+ def tearDown(self):
+ # Close down the second connection.
+ transaction.leave_transaction_management()
+ self.conn2.close()
+
+ def test_concurrent_delete(self):
+ "Deletes on concurrent transactions don't collide and lock the database. Regression for #9479"
+
+ # Create some dummy data
+ b1 = Book(id=1, pagecount=100)
+ b2 = Book(id=2, pagecount=200)
+ b3 = Book(id=3, pagecount=300)
+ b1.save()
+ b2.save()
+ b3.save()
+
+ transaction.commit()
+
+ self.assertEquals(3, Book.objects.count())
+
+ # Delete something using connection 2.
+ cursor2 = self.conn2.cursor()
+ cursor2.execute('DELETE from delete_regress_book WHERE id=1')
+ self.conn2._commit();
+
+ # Now perform a queryset delete that covers the object
+ # deleted in connection 2. This causes an infinite loop
+ # under MySQL InnoDB unless we keep track of already
+ # deleted objects.
+ Book.objects.filter(pagecount__lt=250).delete()
+ transaction.commit()
+ self.assertEquals(1, Book.objects.count())
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