From 35e649b197e16fff0de95562950d22ce7b1a51f6 Mon Sep 17 00:00:00 2001
From: Claude Paroz <claude@2xlibre.net>
Date: Sat, 17 Sep 2016 17:51:13 +0200
Subject: [PATCH] Simplified PostGIS index creation

Less special-casing and code more in line with 'normal' index creation.
---
 .../contrib/gis/db/backends/postgis/schema.py | 74 ++++++-------------
 1 file changed, 23 insertions(+), 51 deletions(-)

diff --git a/django/contrib/gis/db/backends/postgis/schema.py b/django/contrib/gis/db/backends/postgis/schema.py
index c75b65c5f0..4ee46cb3ff 100644
--- a/django/contrib/gis/db/backends/postgis/schema.py
+++ b/django/contrib/gis/db/backends/postgis/schema.py
@@ -6,61 +6,33 @@ class PostGISSchemaEditor(DatabaseSchemaEditor):
     geom_index_ops_nd = 'GIST_GEOMETRY_OPS_ND'
     rast_index_wrapper = 'ST_ConvexHull(%s)'
 
-    sql_add_spatial_index = "CREATE INDEX %(index)s ON %(table)s USING %(index_type)s (%(column)s %(ops)s)"
-
-    def __init__(self, *args, **kwargs):
-        super(PostGISSchemaEditor, self).__init__(*args, **kwargs)
-        self.geometry_sql = []
-
     def geo_quote_name(self, name):
         return self.connection.ops.geo_quote_name(name)
 
-    def column_sql(self, model, field, include_default=False):
-        from django.contrib.gis.db.models.fields import BaseSpatialField
-        if not isinstance(field, BaseSpatialField):
-            return super(PostGISSchemaEditor, self).column_sql(model, field, include_default)
+    def _field_should_be_indexed(self, model, field):
+        if getattr(field, 'spatial_index', False):
+            return True
+        return super(PostGISSchemaEditor, self)._field_should_be_indexed(model, field)
 
-        column_sql = super(PostGISSchemaEditor, self).column_sql(model, field, include_default)
+    def _create_index_sql(self, model, fields, suffix="", sql=None):
+        if len(fields) != 1 or not hasattr(fields[0], 'geodetic'):
+            return super(PostGISSchemaEditor, self)._create_index_sql(model, fields, suffix=suffix, sql=sql)
 
-        if field.spatial_index:
-            # Spatial indexes created the same way for both Geometry and
-            # Geography columns.
-            field_column = self.quote_name(field.column)
-            if field.geom_type == 'RASTER':
-                # For raster fields, wrap index creation SQL statement with ST_ConvexHull.
-                # Indexes on raster columns are based on the convex hull of the raster.
-                field_column = self.rast_index_wrapper % field_column
-                index_ops = ''
-            elif field.geography:
-                index_ops = ''
-            else:
-                # Use either "nd" ops  which are fast on multidimensional cases
-                # or just plain gist index for the 2d case.
-                if field.dim > 2:
-                    index_ops = self.geom_index_ops_nd
-                else:
-                    index_ops = ''
-            self.geometry_sql.append(
-                self.sql_add_spatial_index % {
-                    "index": self.quote_name('%s_%s_id' % (model._meta.db_table, field.column)),
-                    "table": self.quote_name(model._meta.db_table),
-                    "column": field_column,
-                    "index_type": self.geom_index_type,
-                    "ops": index_ops,
-                }
-            )
-        return column_sql
+        field = fields[0]
+        field_column = self.quote_name(field.column)
 
-    def create_model(self, model):
-        super(PostGISSchemaEditor, self).create_model(model)
-        # Create geometry columns
-        for sql in self.geometry_sql:
-            self.execute(sql)
-        self.geometry_sql = []
+        if field.geom_type == 'RASTER':
+            # For raster fields, wrap index creation SQL statement with ST_ConvexHull.
+            # Indexes on raster columns are based on the convex hull of the raster.
+            field_column = self.rast_index_wrapper % field_column
+        elif field.dim > 2 and not field.geography:
+            # Use "nd" ops which are fast on multidimensional cases
+            field_column = "%s %s" % (field_column, self.geom_index_ops_nd)
 
-    def add_field(self, model, field):
-        super(PostGISSchemaEditor, self).add_field(model, field)
-        # Create geometry columns
-        for sql in self.geometry_sql:
-            self.execute(sql)
-        self.geometry_sql = []
+        return self.sql_create_index % {
+            "name": self.quote_name('%s_%s_id' % (model._meta.db_table, field.column)),
+            "table": self.quote_name(model._meta.db_table),
+            "using": "USING %s" % self.geom_index_type,
+            "columns": field_column,
+            "extra": '',
+        }