Fixed #27030 -- Added contrib.postgres.indexes.GinIndex.

django/contrib/postgres/indexes.py

@@ -0,0 +1,12 @@
+from __future__ import unicode_literals
+
+from django.db.models import Index
+
+__all__ = ['GinIndex']
+
+
+class GinIndex(Index):
+    suffix = 'gin'
+
+    def create_sql(self, model, schema_editor):
+        return super(GinIndex, self).create_sql(model, schema_editor, using=' USING gin')

django/db/backends/base/schema.py

@@ -880,6 +880,7 @@ class BaseDatabaseSchemaEditor(object):
         return sql_create_index % {
             "table": self.quote_name(model._meta.db_table),
             "name": self.quote_name(self._create_index_name(model, columns, suffix=suffix)),
+            "using": "",
             "columns": ", ".join(self.quote_name(column) for column in columns),
             "extra": tablespace_sql,
         }

django/db/backends/postgresql/schema.py

@@ -11,6 +11,7 @@ class DatabaseSchemaEditor(BaseDatabaseSchemaEditor):
     sql_delete_sequence = "DROP SEQUENCE IF EXISTS %(sequence)s CASCADE"
     sql_set_sequence_max = "SELECT setval('%(sequence)s', MAX(%(column)s)) FROM %(table)s"
 
+    sql_create_index = "CREATE INDEX %(name)s ON %(table)s%(using)s (%(columns)s)%(extra)s"
     sql_create_varchar_index = "CREATE INDEX %(name)s ON %(table)s (%(columns)s varchar_pattern_ops)%(extra)s"
     sql_create_text_index = "CREATE INDEX %(name)s ON %(table)s (%(columns)s text_pattern_ops)%(extra)s"
 

django/db/models/indexes.py

@@ -42,7 +42,7 @@ class Index(object):
             self.name = 'D%s' % self.name[1:]
         return errors
 
-    def create_sql(self, model, schema_editor):
+    def create_sql(self, model, schema_editor, using=''):
         fields = [model._meta.get_field(field_name) for field_name, order in self.fields_orders]
         tablespace_sql = schema_editor._get_index_tablespace_sql(model, fields)
         quote_name = schema_editor.quote_name
@@ -54,6 +54,7 @@ class Index(object):
             'table': quote_name(model._meta.db_table),
             'name': quote_name(self.name),
             'columns': ', '.join(columns),
+            'using': using,
             'extra': tablespace_sql,
         }
 

docs/ref/contrib/postgres/index.txt

@@ -35,6 +35,7 @@ release. Some fields require higher versions.
     fields
     forms
     functions
+    indexes
     lookups
     operations
     search

docs/ref/contrib/postgres/indexes.txt

@@ -0,0 +1,24 @@
+=================================
+PostgreSQL specific model indexes
+=================================
+
+.. module:: django.contrib.postgres.indexes
+
+.. versionadded:: 1.11
+
+The following are PostgreSQL specific :doc:`indexes </ref/models/indexes>`
+available from the ``django.contrib.postgres.indexes`` module.
+
+``GinIndex``
+============
+
+.. class:: GinIndex()
+
+    Creates a `gin index
+    <https://www.postgresql.org/docs/current/static/gin.html>`_.
+
+    To use this index, you need to activate the `btree_gin extension
+    <https://www.postgresql.org/docs/current/static/btree-gin.html>`_ on
+    PostgreSQL. You can install it using the
+    :class:`~django.contrib.postgres.operations.BtreeGinExtension` migration
+    operation.

docs/ref/models/indexes.txt

@@ -56,3 +56,8 @@ case, a descending index is created as a normal index.
 The name of the index. If ``name`` isn't provided Django will auto-generate a
 name. For compatibility with different databases, index names cannot be longer
 than 30 characters and shouldn't start with a number (0-9) or underscore (_).
+
+.. seealso::
+
+    For a list of PostgreSQL-specific indexes, see
+    :mod:`django.contrib.postgres.indexes`.

tests/postgres_tests/test_indexes.py

@@ -0,0 +1,55 @@
+from django.contrib.postgres.indexes import GinIndex
+from django.db import connection
+
+from . import PostgreSQLTestCase
+from .models import IntegerArrayModel
+
+
+class GinIndexTests(PostgreSQLTestCase):
+
+    def test_repr(self):
+        index = GinIndex(fields=['title'])
+        self.assertEqual(repr(index), "<GinIndex: fields='title'>")
+
+    def test_eq(self):
+        index = GinIndex(fields=['title'])
+        same_index = GinIndex(fields=['title'])
+        another_index = GinIndex(fields=['author'])
+        self.assertEqual(index, same_index)
+        self.assertNotEqual(index, another_index)
+
+    def test_name_auto_generation(self):
+        index = GinIndex(fields=['field'])
+        index.set_name_with_model(IntegerArrayModel)
+        self.assertEqual(index.name, 'postgres_te_field_def2f8_gin')
+
+    def test_deconstruction(self):
+        index = GinIndex(fields=['title'], name='test_title_gin')
+        path, args, kwargs = index.deconstruct()
+        self.assertEqual(path, 'django.contrib.postgres.indexes.GinIndex')
+        self.assertEqual(args, ())
+        self.assertEqual(kwargs, {'fields': ['title'], 'name': 'test_title_gin'})
+
+
+class SchemaTests(PostgreSQLTestCase):
+
+    def get_indexes(self, table):
+        """
+        Get the indexes on the table using a new cursor.
+        """
+        with connection.cursor() as cursor:
+            return connection.introspection.get_indexes(cursor, table)
+
+    def test_gin_index(self):
+        # Ensure the table is there and doesn't have an index.
+        self.assertNotIn('field', self.get_indexes(IntegerArrayModel._meta.db_table))
+        # Add the index
+        index = GinIndex(fields=['field'], name='integer_array_model_field_gin')
+        with connection.schema_editor() as editor:
+            editor.add_index(IntegerArrayModel, index)
+        self.assertIn('field', self.get_indexes(IntegerArrayModel._meta.db_table))
+        self.assertEqual(self.get_indexes(IntegerArrayModel._meta.db_table)['field']['type'], 'gin')
+        # Drop the index
+        with connection.schema_editor() as editor:
+            editor.remove_index(IntegerArrayModel, index)
+        self.assertNotIn('field', self.get_indexes(IntegerArrayModel._meta.db_table))

tests/schema/tests.py

@@ -1803,6 +1803,7 @@ class SchemaTests(TransactionTestCase):
                 editor.sql_create_index % {
                     "table": editor.quote_name(table),
                     "name": editor.quote_name(constraint_name),
+                    "using": "",
                     "columns": editor.quote_name(column),
                     "extra": "",
                 }