Ticket #15507: 15507.2.diff

django/db/backends/mysql/base.py

@@ -150 +150 @@
     requires_explicit_null_ordering_when_grouping = True
     allows_primary_key_0 = False
 
+    def __init__(self, connection):
+        super(DatabaseFeatures, self).__init__(connection)
+        self._storage_engine = None
+
+    def _mysql_storage_engine(self):
+        "Internal method used in Django tests, don't rely on this from your code"
+        if self._storage_engine is None:
+            cursor = self.connection.cursor()
+            cursor.execute('CREATE TABLE INTROSPECT_TEST (X INT)')
+            # This command is MySQL specific; the second column
+            # will tell you the default table type of the created
+            # table. Since all Django's test tables will have the same
+            # table type, that's enough to evaluate the feature.
+            cursor.execute("SHOW TABLE STATUS WHERE Name='INTROSPECT_TEST'")
+            result = cursor.fetchone()
+            cursor.execute('DROP TABLE INTROSPECT_TEST')
+            self._storage_engine = result[1]
+        return self._storage_engine
+
     def _can_introspect_foreign_keys(self):
         "Confirm support for introspected foreign keys"
-        cursor = self.connection.cursor()
-        cursor.execute('CREATE TABLE INTROSPECT_TEST (X INT)')
-        # This command is MySQL specific; the second column
-        # will tell you the default table type of the created
-        # table. Since all Django's test tables will have the same
-        # table type, that's enough to evaluate the feature.
-        cursor.execute("SHOW TABLE STATUS WHERE Name='INTROSPECT_TEST'")
-        result = cursor.fetchone()
-        cursor.execute('DROP TABLE INTROSPECT_TEST')
-        return result[1] != 'MyISAM'
+        return self._mysql_storage_engine() != 'MyISAM'
 
 class DatabaseOperations(BaseDatabaseOperations):
     compiler_module = "django.db.backends.mysql.compiler"
@@ -285 +295 @@
         items_sql = "(%s)" % ", ".join(["%s"] * len(fields))
         return "VALUES " + ", ".join([items_sql] * num_values)
 
+    def savepoint_create_sql(self, sid):
+        return "SAVEPOINT %s" % sid
+
+    def savepoint_commit_sql(self, sid):
+        return "RELEASE SAVEPOINT %s" % sid
+
+    def savepoint_rollback_sql(self, sid):
+        return "ROLLBACK TO SAVEPOINT %s" % sid
+
 class DatabaseWrapper(BaseDatabaseWrapper):
     vendor = 'mysql'
     operators = {
@@ -354 +373 @@
             self.connection = Database.connect(**kwargs)
             self.connection.encoders[SafeUnicode] = self.connection.encoders[unicode]
             self.connection.encoders[SafeString] = self.connection.encoders[str]
+            self.features.uses_savepoints = \
+                self.get_server_version() >= (5, 0, 3)
             connection_created.send(sender=self.__class__, connection=self)
         cursor = self.connection.cursor()
         if new_connection:

docs/releases/1.4.txt

@@ -553 +553 @@
   password reset mechanism and making it available is now much easier. For
   details, see :ref:`auth_password_reset`.
 
+* The MySQL database backend supports taking advantage of savepoint as featured
+  by MySQL version 5.0.3 or newer with the InnoDB storage engine.
+
 Backwards incompatible changes in 1.4
 =====================================
 

docs/topics/db/transactions.txt

@@ -225 +225 @@
 Savepoints
 ==========
 
-A savepoint is a marker within a transaction that enables you to roll back
-part of a transaction, rather than the full transaction. Savepoints are
-available to the PostgreSQL 8 and Oracle backends. Other backends will
-provide the savepoint functions, but they are empty operations - they won't
-actually do anything.
+A savepoint is a marker within a transaction that enables you to roll back part
+of a transaction, rather than the full transaction. Savepoints are available to
+the PostgreSQL 8, Oracle and MySQL (version 5.0.3 and newer, when using the
+InnoDB storage engine) backends. Other backends will provide the savepoint
+functions, but they are empty operations - they won't actually do anything.
+
+.. versionchanged:: 1.4
+   Savepoint support when using the MySQL backend was added in Django 1.4
 
 Savepoints aren't especially useful if you are using the default
 ``autocommit`` behavior of Django. However, if you are using

tests/regressiontests/transactions_regress/tests.py

@@ -4 +4 @@
 from django.db import connection, transaction
 from django.db.transaction import commit_on_success, commit_manually, TransactionManagementError
 from django.test import TransactionTestCase, skipUnlessDBFeature
+from django.utils.unittest import skipIf
 
 from .models import Mod, M2mA, M2mB
 
@@ -165 +166 @@
         except:
             self.fail("A transaction consisting of a failed operation was not closed.")
 
+
 class TestManyToManyAddTransaction(TransactionTestCase):
     def test_manyrelated_add_commit(self):
         "Test for https://code.djangoproject.com/ticket/16818"
@@ -178 +180 @@
         # that the bulk insert was not auto-committed.
         transaction.rollback()
         self.assertEqual(a.others.count(), 1)
+
+
+class SavepointTest(TransactionTestCase):
+
+    @skipUnlessDBFeature('uses_savepoints')
+    def test_savepoint_commit(self):
+        @commit_manually
+        def work():
+            mod = Mod.objects.create(fld=1)
+            pk = mod.pk
+            sid = transaction.savepoint()
+            mod1 = Mod.objects.filter(pk=pk).update(fld=10)
+            transaction.savepoint_commit(sid)
+            mod2 = Mod.objects.get(pk=pk)
+            transaction.commit()
+            self.assertEqual(mod2.fld, 10)
+
+        work()
+
+    @skipIf(connection.vendor == 'mysql' and \
+            connection.features._mysql_storage_engine() == 'MyISAM',
+            "MyISAM MySQL storage engine doesn't support savepoints")
+    @skipUnlessDBFeature('uses_savepoints')
+    def test_savepoint_rollback(self):
+        @commit_manually
+        def work():
+            mod = Mod.objects.create(fld=1)
+            pk = mod.pk
+            sid = transaction.savepoint()
+            mod1 = Mod.objects.filter(pk=pk).update(fld=20)
+            transaction.savepoint_rollback(sid)
+            mod2 = Mod.objects.get(pk=pk)
+            transaction.commit()
+            self.assertEqual(mod2.fld, 1)
+
+        work()