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Fixed #19861 -- Transaction ._dirty flag improvement 

There were a couple of errors in ._dirty flag handling:
  * It started as None, but was never reset to None.
  * The _dirty flag was sometimes used to indicate if the connection
    was inside transaction management, but this was not done
    consistently. This also meant the flag had three separate values.
  * The None value had a special meaning, causing for example inability
    to commit() on new connection unless enter/leave tx management was
    done.
  * The _dirty was tracking "connection in transaction" state, but only
    in managed transactions.
  * Some tests never reset the transaction state of the used connection.
  * And some additional less important changes.

This commit has some potential for regressions, but as the above list
shows, the current situation isn't perfect either.
This commit is contained in:
Anssi Kääriäinen 2013-02-20 03:11:54 +02:00
parent 2108941677
commit 50328f0a61
12 changed files with 161 additions and 69 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

43
django/db/backends/__init__.py
View File

@ -41,7 +41,10 @@ class BaseDatabaseWrapper(object):
# Transaction related attributes
self.transaction_state = []
self.savepoint_state = 0
self._dirty = None
# Tracks if the connection is believed to be in transaction. This is
# set somewhat aggressively, as the DBAPI doesn't make it easy to
# deduce if the connection is in transaction or not.
self._dirty = False
self._thread_ident = thread.get_ident()
self.allow_thread_sharing = allow_thread_sharing
@ -118,8 +121,7 @@ class BaseDatabaseWrapper(object):
stack.
"""
if self._dirty:
self._rollback()
self._dirty = False
self.rollback()
while self.transaction_state:
self.leave_transaction_management()
@ -137,9 +139,6 @@ class BaseDatabaseWrapper(object):
self.transaction_state.append(self.transaction_state[-1])
else:
self.transaction_state.append(settings.TRANSACTIONS_MANAGED)
if self._dirty is None:
self._dirty = False
self._enter_transaction_management(managed)
def leave_transaction_management(self):
@ -153,14 +152,16 @@ class BaseDatabaseWrapper(object):
else:
raise TransactionManagementError(
"This code isn't under transaction management")
# The _leave_transaction_management hook can change the dirty flag,
# so memoize it.
dirty = self._dirty
# We will pass the next status (after leaving the previous state
# behind) to subclass hook.
self._leave_transaction_management(self.is_managed())
if self._dirty:
if dirty:
self.rollback()
raise TransactionManagementError(
"Transaction managed block ended with pending COMMIT/ROLLBACK")
self._dirty = False
def validate_thread_sharing(self):
"""
@ -190,11 +191,7 @@ class BaseDatabaseWrapper(object):
to decide in a managed block of code to decide whether there are open
changes waiting for commit.
"""
if self._dirty is not None:
self._dirty = True
else:
raise TransactionManagementError("This code isn't under transaction "
"management")
self._dirty = True
def set_clean(self):
"""
@ -202,10 +199,7 @@ class BaseDatabaseWrapper(object):
to decide in a managed block of code to decide whether a commit or rollback
should happen.
"""
if self._dirty is not None:
self._dirty = False
else:
raise TransactionManagementError("This code isn't under transaction management")
self._dirty = False
self.clean_savepoints()
def clean_savepoints(self):
@ -233,8 +227,7 @@ class BaseDatabaseWrapper(object):
if top:
top[-1] = flag
if not flag and self.is_dirty():
self._commit()
self.set_clean()
self.commit()
else:
raise TransactionManagementError("This code isn't under transaction "
"management")
@ -245,7 +238,7 @@ class BaseDatabaseWrapper(object):
"""
self.validate_thread_sharing()
if not self.is_managed():
self._commit()
self.commit()
self.clean_savepoints()
else:
self.set_dirty()
@ -256,7 +249,7 @@ class BaseDatabaseWrapper(object):
"""
self.validate_thread_sharing()
if not self.is_managed():
self._rollback()
self.rollback()
else:
self.set_dirty()
@ -343,6 +336,7 @@ class BaseDatabaseWrapper(object):
if self.connection is not None:
self.connection.close()
self.connection = None
self.set_clean()
def cursor(self):
self.validate_thread_sharing()
@ -485,14 +479,13 @@ class BaseDatabaseFeatures(object):
self.connection.managed(True)
cursor = self.connection.cursor()
cursor.execute('CREATE TABLE ROLLBACK_TEST (X INT)')
self.connection._commit()
self.connection.commit()
cursor.execute('INSERT INTO ROLLBACK_TEST (X) VALUES (8)')
self.connection._rollback()
self.connection.rollback()
cursor.execute('SELECT COUNT(X) FROM ROLLBACK_TEST')
count, = cursor.fetchone()
cursor.execute('DROP TABLE ROLLBACK_TEST')
self.connection._commit()
self.connection._dirty = False
self.connection.commit()
finally:
self.connection.leave_transaction_management()
return count == 0

2
django/db/backends/creation.py
View File

@ -385,8 +385,8 @@ class BaseDatabaseCreation(object):
# Create the test database and connect to it. We need to autocommit
# if the database supports it because PostgreSQL doesn't allow
# CREATE/DROP DATABASE statements within transactions.
cursor = self.connection.cursor()
self._prepare_for_test_db_ddl()
cursor = self.connection.cursor()
try:
cursor.execute(
"CREATE DATABASE %s %s" % (qn(test_database_name), suffix))

9
django/db/backends/postgresql_psycopg2/base.py
View File

@ -149,6 +149,8 @@ class DatabaseWrapper(BaseDatabaseWrapper):
exc_info=sys.exc_info()
)
raise
finally:
self.set_clean()
@cached_property
def pg_version(self):
@ -233,10 +235,17 @@ class DatabaseWrapper(BaseDatabaseWrapper):
try:
if self.connection is not None:
self.connection.set_isolation_level(level)
if level == psycopg2.extensions.ISOLATION_LEVEL_AUTOCOMMIT:
self.set_clean()
finally:
self.isolation_level = level
self.features.uses_savepoints = bool(level)
def set_dirty(self):
if ((self.transaction_state and self.transaction_state[-1]) or
not self.features.uses_autocommit):
super(DatabaseWrapper, self).set_dirty()
def _commit(self):
if self.connection is not None:
try:

2
django/db/backends/postgresql_psycopg2/creation.py
View File

@ -82,6 +82,8 @@ class DatabaseCreation(BaseDatabaseCreation):
def _prepare_for_test_db_ddl(self):
"""Rollback and close the active transaction."""
# Make sure there is an open connection.
self.connection.cursor()
self.connection.connection.rollback()
self.connection.connection.set_isolation_level(
psycopg2.extensions.ISOLATION_LEVEL_AUTOCOMMIT)

10
django/db/backends/util.py
View File

@ -19,13 +19,9 @@ class CursorWrapper(object):
self.cursor = cursor
self.db = db
def set_dirty(self):
if self.db.is_managed():
self.db.set_dirty()
def __getattr__(self, attr):
if attr in ('execute', 'executemany', 'callproc'):
self.set_dirty()
self.db.set_dirty()
return getattr(self.cursor, attr)
def __iter__(self):
@ -35,7 +31,7 @@ class CursorWrapper(object):
class CursorDebugWrapper(CursorWrapper):
def execute(self, sql, params=()):
self.set_dirty()
self.db.set_dirty()
start = time()
try:
return self.cursor.execute(sql, params)
@ -52,7 +48,7 @@ class CursorDebugWrapper(CursorWrapper):
)
def executemany(self, sql, param_list):
self.set_dirty()
self.db.set_dirty()
start = time()
try:
return self.cursor.executemany(sql, param_list)

5
django/db/models/sql/compiler.py
View File

@ -687,11 +687,6 @@ class SQLCompiler(object):
resolve_columns = hasattr(self, 'resolve_columns')
fields = None
has_aggregate_select = bool(self.query.aggregate_select)
# Set transaction dirty if we're using SELECT FOR UPDATE to ensure
# a subsequent commit/rollback is executed, so any database locks
# are released.
if self.query.select_for_update and transaction.is_managed(self.using):
transaction.set_dirty(self.using)
for rows in self.execute_sql(MULTI):
for row in rows:
if resolve_columns:

5
docs/ref/models/querysets.txt
View File

@ -1249,11 +1249,6 @@ make the call non-blocking. If a conflicting lock is already acquired by
another transaction, :exc:`~django.db.DatabaseError` will be raised when the
queryset is evaluated.
Note that using ``select_for_update()`` will cause the current transaction to be
considered dirty, if under transaction management. This is to ensure that
Django issues a ``COMMIT`` or ``ROLLBACK``, releasing any locks held by the
``SELECT FOR UPDATE``.
Currently, the ``postgresql_psycopg2``, ``oracle``, and ``mysql`` database
backends support ``select_for_update()``. However, MySQL has no support for the
``nowait`` argument. Obviously, users of external third-party backends should

4
tests/delete_regress/tests.py
View File

@ -23,11 +23,13 @@ class DeleteLockingTest(TransactionTestCase):
# Put both DB connections into managed transaction mode
transaction.enter_transaction_management()
transaction.managed(True)
self.conn2._enter_transaction_management(True)
self.conn2.enter_transaction_management()
self.conn2.managed(True)
def tearDown(self):
# Close down the second connection.
transaction.leave_transaction_management()
self.conn2.abort()
self.conn2.close()
@skipUnlessDBFeature('test_db_allows_multiple_connections')

13
tests/middleware/tests.py
View File

@ -683,6 +683,9 @@ class TransactionMiddlewareTest(TransactionTestCase):
self.response = HttpResponse()
self.response.status_code = 200
def tearDown(self):
transaction.abort()
def test_request(self):
TransactionMiddleware().process_request(self.request)
self.assertTrue(transaction.is_managed())
@ -697,10 +700,14 @@ class TransactionMiddlewareTest(TransactionTestCase):
self.assertEqual(Band.objects.count(), 1)
def test_unmanaged_response(self):
transaction.enter_transaction_management()
transaction.managed(False)
self.assertEqual(Band.objects.count(), 0)
TransactionMiddleware().process_response(self.request, self.response)
self.assertFalse(transaction.is_managed())
self.assertFalse(transaction.is_dirty())
# The transaction middleware doesn't commit/rollback if management
# has been disabled.
self.assertTrue(transaction.is_dirty())
def test_exception(self):
transaction.enter_transaction_management()
@ -708,8 +715,8 @@ class TransactionMiddlewareTest(TransactionTestCase):
Band.objects.create(name='The Beatles')
self.assertTrue(transaction.is_dirty())
TransactionMiddleware().process_exception(self.request, None)
self.assertEqual(Band.objects.count(), 0)
self.assertFalse(transaction.is_dirty())
self.assertEqual(Band.objects.count(), 0)
def test_failing_commit(self):
# It is possible that connection.commit() fails. Check that
@ -724,8 +731,8 @@ class TransactionMiddlewareTest(TransactionTestCase):
self.assertTrue(transaction.is_dirty())
with self.assertRaises(IntegrityError):
TransactionMiddleware().process_response(self.request, None)
self.assertEqual(Band.objects.count(), 0)
self.assertFalse(transaction.is_dirty())
self.assertEqual(Band.objects.count(), 0)
self.assertFalse(transaction.is_managed())
finally:
del connections[DEFAULT_DB_ALIAS].commit

23
tests/select_for_update/tests.py
View File

@ -24,7 +24,7 @@ requires_threading = unittest.skipUnless(threading, 'requires threading')
class SelectForUpdateTests(TransactionTestCase):
def setUp(self):
transaction.enter_transaction_management(True)
transaction.enter_transaction_management()
transaction.managed(True)
self.person = Person.objects.create(name='Reinhardt')
@ -48,9 +48,8 @@ class SelectForUpdateTests(TransactionTestCase):
try:
# We don't really care if this fails - some of the tests will set
# this in the course of their run.
transaction.managed(False)
transaction.leave_transaction_management()
self.new_connection.leave_transaction_management()
transaction.abort()
self.new_connection.abort()
except transaction.TransactionManagementError:
pass
self.new_connection.close()
@ -73,7 +72,7 @@ class SelectForUpdateTests(TransactionTestCase):
def end_blocking_transaction(self):
# Roll back the blocking transaction.
self.new_connection._rollback()
self.new_connection.rollback()
def has_for_update_sql(self, tested_connection, nowait=False):
# Examine the SQL that was executed to determine whether it
@ -119,6 +118,7 @@ class SelectForUpdateTests(TransactionTestCase):
"""
self.start_blocking_transaction()
status = []
thread = threading.Thread(
target=self.run_select_for_update,
args=(status,),
@ -164,7 +164,7 @@ class SelectForUpdateTests(TransactionTestCase):
try:
# We need to enter transaction management again, as this is done on
# per-thread basis
transaction.enter_transaction_management(True)
transaction.enter_transaction_management()
transaction.managed(True)
people = list(
Person.objects.all().select_for_update(nowait=nowait)
@ -177,6 +177,7 @@ class SelectForUpdateTests(TransactionTestCase):
finally:
# This method is run in a separate thread. It uses its own
# database connection. Close it without waiting for the GC.
transaction.abort()
connection.close()
@requires_threading
@ -271,13 +272,3 @@ class SelectForUpdateTests(TransactionTestCase):
"""
people = list(Person.objects.select_for_update())
self.assertTrue(transaction.is_dirty())
@skipUnlessDBFeature('has_select_for_update')
def test_transaction_not_dirty_unmanaged(self):
""" If we're not under txn management, the txn will never be
marked as dirty.
"""
transaction.managed(False)
transaction.leave_transaction_management()
people = list(Person.objects.select_for_update())
self.assertFalse(transaction.is_dirty())

2
tests/transactions/tests.py
View File

@ -165,7 +165,6 @@ class TransactionRollbackTests(TransactionTestCase):
def execute_bad_sql(self):
cursor = connection.cursor()
cursor.execute("INSERT INTO transactions_reporter (first_name, last_name) VALUES ('Douglas', 'Adams');")
transaction.set_dirty()
@skipUnlessDBFeature('requires_rollback_on_dirty_transaction')
def test_bad_sql(self):
@ -306,5 +305,4 @@ class TransactionContextManagerTests(TransactionTestCase):
with transaction.commit_on_success():
cursor = connection.cursor()
cursor.execute("INSERT INTO transactions_reporter (first_name, last_name) VALUES ('Douglas', 'Adams');")
transaction.set_dirty()
transaction.rollback()

112
tests/transactions_regress/tests.py
View File

@ -138,7 +138,8 @@ class TestTransactionClosing(TransactionTestCase):
@transaction.commit_on_success
def create_system_user():
"Create a user in a transaction"
user = User.objects.create_user(username='system', password='iamr00t', email='root@SITENAME.com')
user = User.objects.create_user(username='system', password='iamr00t',
email='root@SITENAME.com')
# Redundant, just makes sure the user id was read back from DB
Mod.objects.create(fld=user.pk)
@ -161,6 +162,83 @@ class TestTransactionClosing(TransactionTestCase):
"""
self.test_failing_query_transaction_closed()
@skipIf(connection.vendor == 'sqlite' and
(connection.settings_dict['NAME'] == ':memory:' or
not connection.settings_dict['NAME']),
'Test uses multiple connections, but in-memory sqlite does not support this')
class TestNewConnection(TransactionTestCase):
"""
Check that new connections don't have special behaviour.
"""
def setUp(self):
self._old_backend = connections[DEFAULT_DB_ALIAS]
settings = self._old_backend.settings_dict.copy()
opts = settings['OPTIONS'].copy()
if 'autocommit' in opts:
opts['autocommit'] = False
settings['OPTIONS'] = opts
new_backend = self._old_backend.__class__(settings, DEFAULT_DB_ALIAS)
connections[DEFAULT_DB_ALIAS] = new_backend
def tearDown(self):
try:
connections[DEFAULT_DB_ALIAS].abort()
except Exception:
import ipdb; ipdb.set_trace()
finally:
connections[DEFAULT_DB_ALIAS].close()
connections[DEFAULT_DB_ALIAS] = self._old_backend
def test_commit(self):
"""
Users are allowed to commit and rollback connections.
"""
# The starting value is False, not None.
self.assertIs(connection._dirty, False)
list(Mod.objects.all())
self.assertTrue(connection.is_dirty())
connection.commit()
self.assertFalse(connection.is_dirty())
list(Mod.objects.all())
self.assertTrue(connection.is_dirty())
connection.rollback()
self.assertFalse(connection.is_dirty())
def test_enter_exit_management(self):
orig_dirty = connection._dirty
connection.enter_transaction_management()
connection.leave_transaction_management()
self.assertEqual(orig_dirty, connection._dirty)
def test_commit_unless_managed(self):
cursor = connection.cursor()
cursor.execute("INSERT into transactions_regress_mod (fld) values (2)")
connection.commit_unless_managed()
self.assertFalse(connection.is_dirty())
self.assertEqual(len(Mod.objects.all()), 1)
self.assertTrue(connection.is_dirty())
connection.commit_unless_managed()
self.assertFalse(connection.is_dirty())
def test_commit_unless_managed_in_managed(self):
cursor = connection.cursor()
connection.enter_transaction_management()
transaction.managed(True)
cursor.execute("INSERT into transactions_regress_mod (fld) values (2)")
connection.commit_unless_managed()
self.assertTrue(connection.is_dirty())
connection.rollback()
self.assertFalse(connection.is_dirty())
self.assertEqual(len(Mod.objects.all()), 0)
connection.commit()
connection.leave_transaction_management()
self.assertFalse(connection.is_dirty())
self.assertEqual(len(Mod.objects.all()), 0)
self.assertTrue(connection.is_dirty())
connection.commit_unless_managed()
self.assertFalse(connection.is_dirty())
self.assertEqual(len(Mod.objects.all()), 0)
@skipUnless(connection.vendor == 'postgresql',
"This test only valid for PostgreSQL")
@ -171,9 +249,11 @@ class TestPostgresAutocommit(TransactionTestCase):
"""
def setUp(self):
from psycopg2.extensions import (ISOLATION_LEVEL_AUTOCOMMIT,
ISOLATION_LEVEL_READ_COMMITTED)
ISOLATION_LEVEL_READ_COMMITTED,
TRANSACTION_STATUS_IDLE)
self._autocommit = ISOLATION_LEVEL_AUTOCOMMIT
self._read_committed = ISOLATION_LEVEL_READ_COMMITTED
self._idle = TRANSACTION_STATUS_IDLE
# We want a clean backend with autocommit = True, so
# first we need to do a bit of work to have that.
@ -186,7 +266,11 @@ class TestPostgresAutocommit(TransactionTestCase):
connections[DEFAULT_DB_ALIAS] = new_backend
def tearDown(self):
connections[DEFAULT_DB_ALIAS] = self._old_backend
try:
connections[DEFAULT_DB_ALIAS].abort()
finally:
connections[DEFAULT_DB_ALIAS].close()
connections[DEFAULT_DB_ALIAS] = self._old_backend
def test_initial_autocommit_state(self):
self.assertTrue(connection.features.uses_autocommit)
@ -214,6 +298,26 @@ class TestPostgresAutocommit(TransactionTestCase):
transaction.leave_transaction_management()
self.assertEqual(connection.isolation_level, self._autocommit)
def test_enter_autocommit(self):
transaction.enter_transaction_management()
transaction.managed(True)
self.assertEqual(connection.isolation_level, self._read_committed)
list(Mod.objects.all())
self.assertTrue(transaction.is_dirty())
# Enter autocommit mode again.
transaction.enter_transaction_management(False)
transaction.managed(False)
self.assertFalse(transaction.is_dirty())
self.assertEqual(
connection.connection.get_transaction_status(),
self._idle)
list(Mod.objects.all())
self.assertFalse(transaction.is_dirty())
transaction.leave_transaction_management()
self.assertEqual(connection.isolation_level, self._read_committed)
transaction.leave_transaction_management()
self.assertEqual(connection.isolation_level, self._autocommit)
class TestManyToManyAddTransaction(TransactionTestCase):
def test_manyrelated_add_commit(self):
@ -247,7 +351,7 @@ class SavepointTest(TransactionTestCase):
work()
@skipIf(connection.vendor == 'mysql' and \
@skipIf(connection.vendor == 'mysql' and
connection.features._mysql_storage_engine == 'MyISAM',
"MyISAM MySQL storage engine doesn't support savepoints")
@skipUnlessDBFeature('uses_savepoints')