innov
/
django1
1
0
Fork 0
Code Issues Pull Requests 1 Projects Releases Wiki Activity

Fixed #24757 -- Recreated MySQL index when needed during combined index removal 

Thanks Thomas Recouvreux for the report and Tim Graham for the tests and
review.
This commit is contained in:
Claude Paroz 2015-05-13 17:40:57 +02:00
parent 0eaef8e527
commit ae635cc365
4 changed files with 70 additions and 18 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

31
django/db/backends/base/schema.py
View File

@ -315,15 +315,7 @@ class BaseDatabaseSchemaEditor(object):
news = set(tuple(fields) for fields in new_unique_together)
# Deleted uniques
for fields in olds.difference(news):
columns = [model._meta.get_field(field).column for field in fields]
constraint_names = self._constraint_names(model, columns, unique=True)
if len(constraint_names) != 1:
raise ValueError("Found wrong number (%s) of constraints for %s(%s)" % (
len(constraint_names),
model._meta.db_table,
", ".join(columns),
))
self.execute(self._delete_constraint_sql(self.sql_delete_unique, model, constraint_names[0]))
self._delete_composed_index(model, fields, {'unique': True}, self.sql_delete_unique)
# Created uniques
for fields in news.difference(olds):
columns = [model._meta.get_field(field).column for field in fields]
@ -339,20 +331,23 @@ class BaseDatabaseSchemaEditor(object):
news = set(tuple(fields) for fields in new_index_together)
# Deleted indexes
for fields in olds.difference(news):
columns = [model._meta.get_field(field).column for field in fields]
constraint_names = self._constraint_names(model, list(columns), index=True)
if len(constraint_names) != 1:
raise ValueError("Found wrong number (%s) of constraints for %s(%s)" % (
len(constraint_names),
model._meta.db_table,
", ".join(columns),
))
self.execute(self._delete_constraint_sql(self.sql_delete_index, model, constraint_names[0]))
self._delete_composed_index(model, fields, {'index': True}, self.sql_delete_index)
# Created indexes
for field_names in news.difference(olds):
fields = [model._meta.get_field(field) for field in field_names]
self.execute(self._create_index_sql(model, fields, suffix="_idx"))
def _delete_composed_index(self, model, fields, constraint_kwargs, sql):
columns = [model._meta.get_field(field).column for field in fields]
constraint_names = self._constraint_names(model, columns, **constraint_kwargs)
if len(constraint_names) != 1:
raise ValueError("Found wrong number (%s) of constraints for %s(%s)" % (
len(constraint_names),
model._meta.db_table,
", ".join(columns),
))
self.execute(self._delete_constraint_sql(sql, model, constraint_names[0]))
def alter_db_table(self, model, old_db_table, new_db_table):
"""
Renames the table a model points to.

18
django/db/backends/mysql/schema.py
View File

@ -62,6 +62,24 @@ class DatabaseSchemaEditor(BaseDatabaseSchemaEditor):
field.db_index = False
return super(DatabaseSchemaEditor, self)._model_indexes_sql(model)
def _delete_composed_index(self, model, fields, *args):
"""
MySQL can remove an implicit FK index on a field when that field is
covered by another index like a unique_together. "covered" here means
that the more complex index starts like the simpler one.
http://bugs.mysql.com/bug.php?id=37910 / Django ticket #24757
We check here before removing the [unique|index]_together if we have to
recreate a FK index.
"""
first_field = model._meta.get_field(fields[0])
if first_field.get_internal_type() == 'ForeignKey':
constraint_names = self._constraint_names(model, fields[0], index=True)
if not constraint_names:
self.execute(
self._create_index_sql(model, [model._meta.get_field(fields[0])], suffix="")
)
return super(DatabaseSchemaEditor, self)._delete_composed_index(model, fields, *args)
def _alter_column_type_sql(self, table, old_field, new_field, new_type):
# Keep null property of old field, if it has changed, it will be handled separately
if old_field.null:

3
docs/releases/1.8.2.txt
View File

@ -27,3 +27,6 @@ Bugfixes
:ticket:`24712`).
* Fixed ``isnull`` lookup for ``HStoreField`` (:ticket:`24751`).
* Fixed a MySQL crash when a migration removes a combined index (unique_together
or index_together) containing a foreign key (:ticket:`24757`).

36
tests/schema/tests.py
View File

@ -1084,6 +1084,24 @@ class SchemaTests(TransactionTestCase):
self.assertRaises(IntegrityError, UniqueTest.objects.create, year=2012, slug="foo")
UniqueTest.objects.all().delete()
def test_unique_together_with_fk(self):
"""
Tests removing and adding unique_together constraints that include
a foreign key.
"""
# Create the table
with connection.schema_editor() as editor:
editor.create_model(Author)
editor.create_model(Book)
# Ensure the fields are unique to begin with
self.assertEqual(Book._meta.unique_together, ())
# Add the unique_together constraint
with connection.schema_editor() as editor:
editor.alter_unique_together(Book, [], [['author', 'title']])
# Alter it back
with connection.schema_editor() as editor:
editor.alter_unique_together(Book, [['author', 'title']], [])
def test_index_together(self):
"""
Tests removing and adding index_together constraints on a model.
@ -1127,6 +1145,24 @@ class SchemaTests(TransactionTestCase):
),
)
def test_index_together_with_fk(self):
"""
Tests removing and adding index_together constraints that include
a foreign key.
"""
# Create the table
with connection.schema_editor() as editor:
editor.create_model(Author)
editor.create_model(Book)
# Ensure the fields are unique to begin with
self.assertEqual(Book._meta.index_together, ())
# Add the unique_together constraint
with connection.schema_editor() as editor:
editor.alter_index_together(Book, [], [['author', 'title']])
# Alter it back
with connection.schema_editor() as editor:
editor.alter_index_together(Book, [['author', 'title']], [])
def test_create_index_together(self):
"""
Tests creating models with index_together already defined