def other_thread():
try:
with transaction.atomic():
Reporter.objects.select_for_update().get(id=1)
main_thread_ready.wait()
# 1) This line locks... (see below for 2)
Reporter.objects.exclude(id=1).update(id=2)
finally:
# This is the thread-local connection, not the main connection.
connection.close()
def test_hooks_cleared_on_reconnect(self):
with transaction.atomic():
self.do(1)
connection.close()
connection.connect()
with transaction.atomic():
self.do(2)
self.assertDone([2])
def test_signal(self):
data = {}
def receiver(sender, connection, **kwargs):
data["connection"] = connection
connection_created.connect(receiver)
connection.close()
connection.cursor()
self.assertIs(data["connection"].connection, connection.connection)
connection_created.disconnect(receiver)
data.clear()
connection.cursor()
self.assertEqual(data, {})
def test_atomic_prevents_queries_in_broken_transaction_after_client_close(
self):
with transaction.atomic():
Reporter.objects.create(first_name="Archibald",
last_name="Haddock")
connection.close()
# The connection is closed and the transaction is marked as
# needing rollback. This will raise an InterfaceError on databases
# that refuse to create cursors on closed connections (PostgreSQL)
# and a TransactionManagementError on other databases.
with self.assertRaises(Error):
Reporter.objects.create(first_name="Cuthbert",
last_name="Calculus")
# The connection is usable again .
self.assertEqual(Reporter.objects.count(), 0)
def test_is_usable_after_database_disconnects(self):
"""
is_usable() doesn't crash when the database disconnects (#21553).
"""
# Open a connection to the database.
with connection.cursor():
pass
# Emulate a connection close by the database.
connection._close()
# Even then is_usable() should not raise an exception.
try:
self.assertFalse(connection.is_usable())
finally:
# Clean up the mess created by connection._close(). Since the
# connection is already closed, this crashes on some backends.
try:
connection.close()
except Exception:
pass
def raw(status):
try:
list(
Person.objects.raw(
'SELECT * FROM %s %s' % (
Person._meta.db_table,
connection.ops.for_update_sql(nowait=True)
)
)
)
except DatabaseError as e:
status.append(e)
finally:
# This method is run in a separate thread. It uses its own
# database connection. Close it without waiting for the GC.
# Connection cannot be closed on Oracle because cursor is still
# open.
if connection.vendor != 'oracle':
connection.close()
def run_select_for_update(self, status, **kwargs):
"""
Utility method that runs a SELECT FOR UPDATE against all
Person instances. After the select_for_update, it attempts
to update the name of the only record, save, and commit.
This function expects to run in a separate thread.
"""
status.append('started')
try:
# We need to enter transaction management again, as this is done on
# per-thread basis
with transaction.atomic():
person = Person.objects.select_for_update(**kwargs).get()
person.name = 'Fred'
person.save()
except (DatabaseError, Person.DoesNotExist) as e:
status.append(e)
finally:
# This method is run in a separate thread. It uses its own
# database connection. Close it without waiting for the GC.
connection.close()
def update_birthday_slowly():
try:
Person.objects.update_or_create(first_name='John', defaults={'birthday': birthday_sleep})
finally:
# Avoid leaking connection for Oracle
connection.close()