Fixed #18130 -- Made the isolation level configurable on PostgreSQL. (e0449316) · Commits · Dom Sekotill / django

django/db/backends/postgresql_psycopg2/base.py

+7 −2

Original line number	Diff line number	Diff line
		@@ -83,7 +83,8 @@ class DatabaseWrapper(BaseDatabaseWrapper):
		if autocommit:
		level = psycopg2.extensions.ISOLATION_LEVEL_AUTOCOMMIT
		else:
		level = psycopg2.extensions.ISOLATION_LEVEL_READ_COMMITTED
		level = self.settings_dict["OPTIONS"].get('isolation_level',
		psycopg2.extensions.ISOLATION_LEVEL_READ_COMMITTED)
		self._set_isolation_level(level)
		self.ops = DatabaseOperations(self)
		self.client = DatabaseClient(self)
		@@ -104,6 +105,8 @@ class DatabaseWrapper(BaseDatabaseWrapper):
		conn_params.update(settings_dict['OPTIONS'])
		if 'autocommit' in conn_params:
		del conn_params['autocommit']
		if 'isolation_level' in conn_params:
		del conn_params['isolation_level']
		if settings_dict['USER']:
		conn_params['user'] = settings_dict['USER']
		if settings_dict['PASSWORD']:
		@@ -170,7 +173,9 @@ class DatabaseWrapper(BaseDatabaseWrapper):
		the same transaction is visible across all the queries.
		"""
		if self.features.uses_autocommit and managed and not self.isolation_level:
		self._set_isolation_level(psycopg2.extensions.ISOLATION_LEVEL_READ_COMMITTED)
		level = self.settings_dict["OPTIONS"].get('isolation_level',
		psycopg2.extensions.ISOLATION_LEVEL_READ_COMMITTED)
		self._set_isolation_level(level)

		def _leave_transaction_management(self, managed):
		"""

docs/ref/databases.txt

+33 −2

Original line number	Diff line number	Diff line
		@@ -143,8 +143,11 @@ autocommit behavior is enabled by setting the ``autocommit`` key in
		the :setting:`OPTIONS` part of your database configuration in
		:setting:`DATABASES`::

		DATABASES = {
		# ...
		'OPTIONS': {
		'autocommit': True,
		},
		}

		In this configuration, Django still ensures that :ref:`delete()
		@@ -168,6 +171,34 @@ You should also audit your existing code for any instances of this behavior
		before enabling this feature. It's faster, but it provides less automatic
		protection for multi-call operations.

		Isolation level
		~~~~~~~~~~~~~~~

		.. versionadded:: 1.6

		Like PostgreSQL itself, Django defaults to the ``READ COMMITTED`` `isolation
		level <postgresql-isolation-levels>`_. If you need a higher isolation level
		such as ``REPEATABLE READ`` or ``SERIALIZABLE``, set it in the
		:setting:`OPTIONS` part of your database configuration in
		:setting:`DATABASES`::

		import psycopg2.extensions

		DATABASES = {
		# ...
		'OPTIONS': {
		'isolation_level': psycopg2.extensions.ISOLATION_LEVEL_SERIALIZABLE,
		},
		}

		.. note::

		Under higher isolation levels, your application should be prepared to
		handle exceptions raised on serialization failures. This option is
		designed for advanced uses.

		.. _postgresql-isolation-levels: http://www.postgresql.org/docs/devel/static/transaction-iso.html

		Indexes for ``varchar`` and ``text`` columns
		~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

docs/releases/1.6.txt

+2 −0

Original line number	Diff line number	Diff line
		@@ -125,6 +125,8 @@ Minor features
		* The admin list columns have a ``column-<field_name>`` class in the HTML
		so the columns header can be styled with CSS, e.g. to set a column width.

		* The isolation level can be customized under PostgreSQL.

		Backwards incompatible changes in 1.6
		=====================================

tests/transactions_regress/tests.py

+13 −11

Original line number	Diff line number	Diff line
		@@ -242,17 +242,18 @@ class TestNewConnection(TransactionTestCase):

		@skipUnless(connection.vendor == 'postgresql',
		"This test only valid for PostgreSQL")
		class TestPostgresAutocommit(TransactionTestCase):
		class TestPostgresAutocommitAndIsolation(TransactionTestCase):
		"""
		Tests to make sure psycopg2's autocommit mode is restored after entering
		and leaving transaction management. Refs #16047.
		Tests to make sure psycopg2's autocommit mode and isolation level
		is restored after entering and leaving transaction management.
		Refs #16047, #18130.
		"""
		def setUp(self):
		from psycopg2.extensions import (ISOLATION_LEVEL_AUTOCOMMIT,
		ISOLATION_LEVEL_READ_COMMITTED,
		ISOLATION_LEVEL_SERIALIZABLE,
		TRANSACTION_STATUS_IDLE)
		self._autocommit = ISOLATION_LEVEL_AUTOCOMMIT
		self._read_committed = ISOLATION_LEVEL_READ_COMMITTED
		self._serializable = ISOLATION_LEVEL_SERIALIZABLE
		self._idle = TRANSACTION_STATUS_IDLE

		# We want a clean backend with autocommit = True, so
		@@ -261,6 +262,7 @@ class TestPostgresAutocommit(TransactionTestCase):
		settings = self._old_backend.settings_dict.copy()
		opts = settings['OPTIONS'].copy()
		opts['autocommit'] = True
		opts['isolation_level'] = ISOLATION_LEVEL_SERIALIZABLE
		settings['OPTIONS'] = opts
		new_backend = self._old_backend.__class__(settings, DEFAULT_DB_ALIAS)
		connections[DEFAULT_DB_ALIAS] = new_backend
		@@ -279,7 +281,7 @@ class TestPostgresAutocommit(TransactionTestCase):
		def test_transaction_management(self):
		transaction.enter_transaction_management()
		transaction.managed(True)
		self.assertEqual(connection.isolation_level, self._read_committed)
		self.assertEqual(connection.isolation_level, self._serializable)

		transaction.leave_transaction_management()
		self.assertEqual(connection.isolation_level, self._autocommit)
		@@ -287,13 +289,13 @@ class TestPostgresAutocommit(TransactionTestCase):
		def test_transaction_stacking(self):
		transaction.enter_transaction_management()
		transaction.managed(True)
		self.assertEqual(connection.isolation_level, self._read_committed)
		self.assertEqual(connection.isolation_level, self._serializable)

		transaction.enter_transaction_management()
		self.assertEqual(connection.isolation_level, self._read_committed)
		self.assertEqual(connection.isolation_level, self._serializable)

		transaction.leave_transaction_management()
		self.assertEqual(connection.isolation_level, self._read_committed)
		self.assertEqual(connection.isolation_level, self._serializable)

		transaction.leave_transaction_management()
		self.assertEqual(connection.isolation_level, self._autocommit)
		@@ -301,7 +303,7 @@ class TestPostgresAutocommit(TransactionTestCase):
		def test_enter_autocommit(self):
		transaction.enter_transaction_management()
		transaction.managed(True)
		self.assertEqual(connection.isolation_level, self._read_committed)
		self.assertEqual(connection.isolation_level, self._serializable)
		list(Mod.objects.all())
		self.assertTrue(transaction.is_dirty())
		# Enter autocommit mode again.
		@@ -314,7 +316,7 @@ class TestPostgresAutocommit(TransactionTestCase):
		list(Mod.objects.all())
		self.assertFalse(transaction.is_dirty())
		transaction.leave_transaction_management()
		self.assertEqual(connection.isolation_level, self._read_committed)
		self.assertEqual(connection.isolation_level, self._serializable)
		transaction.leave_transaction_management()
		self.assertEqual(connection.isolation_level, self._autocommit)