Ensure cursors are closed when no longer needed.

This commit touchs various parts of the code base and test framework. Any
found usage of opening a cursor for the sake of initializing a connection
has been replaced with 'ensure_connection()'.

django/db/models/query.py

@@ -1522,54 +1522,59 @@ class RawQuerySet(object):
 
         query = iter(self.query)
 
-        # Find out which columns are model's fields, and which ones should be
-        # annotated to the model.
-        for pos, column in enumerate(self.columns):
-            if column in self.model_fields:
-                model_init_field_names[self.model_fields[column].attname] = pos
-            else:
-                annotation_fields.append((column, pos))
+        try:
+            # Find out which columns are model's fields, and which ones should be
+            # annotated to the model.
+            for pos, column in enumerate(self.columns):
+                if column in self.model_fields:
+                    model_init_field_names[self.model_fields[column].attname] = pos
+                else:
+                    annotation_fields.append((column, pos))
 
-        # Find out which model's fields are not present in the query.
-        skip = set()
-        for field in self.model._meta.fields:
-            if field.attname not in model_init_field_names:
-                skip.add(field.attname)
-        if skip:
-            if self.model._meta.pk.attname in skip:
-                raise InvalidQuery('Raw query must include the primary key')
-            model_cls = deferred_class_factory(self.model, skip)
-        else:
-            model_cls = self.model
-            # All model's fields are present in the query. So, it is possible
-            # to use *args based model instantation. For each field of the model,
-            # record the query column position matching that field.
-            model_init_field_pos = []
+            # Find out which model's fields are not present in the query.
+            skip = set()
             for field in self.model._meta.fields:
-                model_init_field_pos.append(model_init_field_names[field.attname])
-        if need_resolv_columns:
-            fields = [self.model_fields.get(c, None) for c in self.columns]
-        # Begin looping through the query values.
-        for values in query:
-            if need_resolv_columns:
-                values = compiler.resolve_columns(values, fields)
-            # Associate fields to values
+                if field.attname not in model_init_field_names:
+                    skip.add(field.attname)
             if skip:
-                model_init_kwargs = {}
-                for attname, pos in six.iteritems(model_init_field_names):
-                    model_init_kwargs[attname] = values[pos]
-                instance = model_cls(**model_init_kwargs)
+                if self.model._meta.pk.attname in skip:
+                    raise InvalidQuery('Raw query must include the primary key')
+                model_cls = deferred_class_factory(self.model, skip)
             else:
-                model_init_args = [values[pos] for pos in model_init_field_pos]
-                instance = model_cls(*model_init_args)
-            if annotation_fields:
-                for column, pos in annotation_fields:
-                    setattr(instance, column, values[pos])
+                model_cls = self.model
+                # All model's fields are present in the query. So, it is possible
+                # to use *args based model instantation. For each field of the model,
+                # record the query column position matching that field.
+                model_init_field_pos = []
+                for field in self.model._meta.fields:
+                    model_init_field_pos.append(model_init_field_names[field.attname])
+            if need_resolv_columns:
+                fields = [self.model_fields.get(c, None) for c in self.columns]
+            # Begin looping through the query values.
+            for values in query:
+                if need_resolv_columns:
+                    values = compiler.resolve_columns(values, fields)
+                # Associate fields to values
+                if skip:
+                    model_init_kwargs = {}
+                    for attname, pos in six.iteritems(model_init_field_names):
+                        model_init_kwargs[attname] = values[pos]
+                    instance = model_cls(**model_init_kwargs)
+                else:
+                    model_init_args = [values[pos] for pos in model_init_field_pos]
+                    instance = model_cls(*model_init_args)
+                if annotation_fields:
+                    for column, pos in annotation_fields:
+                        setattr(instance, column, values[pos])
 
-            instance._state.db = db
-            instance._state.adding = False
+                instance._state.db = db
+                instance._state.adding = False
 
-            yield instance
+                yield instance
+        finally:
+            # Done iterating the Query. If it has its own cursor, close it.
+            if hasattr(self.query, 'cursor') and self.query.cursor:
+                self.query.cursor.close()
 
     def __repr__(self):
         text = self.raw_query