Optimize SchedulerReportClient.delete_resource_provider

This is used to optimize the SchedulerReportClient
delete_resource_provider method when deleting a compute
node and its related resource provider which happens
in both the API when a compute service is deleted and
in the compute service in the update_available_resource
method for orphan nodes (so the new InstanceList query
method needs to be remotable).

The actual DB query stuff in here is tested in the
nova.tests.functional.wsgi.test_services code.

Change-Id: Id033e8f95f853ccfc34bd350be6df11c1bfb1b7d
Related-Bug: #1811726

nova/objects/instance.py

@@ -1310,7 +1310,8 @@ class InstanceList(base.ObjectListBase, base.NovaObject):
     # Version 2.2: Pagination for get_active_by_window_joined()
     # Version 2.3: Add get_count_by_vm_state()
     # Version 2.4: Add get_counts()
-    VERSION = '2.4'
+    # Version 2.5: Add get_uuids_by_host_and_node()
+    VERSION = '2.5'
 
     fields = {
         'objects': fields.ListOfObjectsField('Instance'),
@@ -1373,6 +1374,24 @@ def get_by_host_and_node(cls, context, host, node, expected_attrs=None):
         return _make_instance_list(context, cls(), db_inst_list,
                                    expected_attrs)
 
+    @staticmethod
+    @db_api.pick_context_manager_reader
+    def _get_uuids_by_host_and_node(context, host, node):
+        return context.session.query(
+            models.Instance.uuid).filter_by(
+            host=host).filter_by(node=node).filter_by(deleted=0).all()
+
+    @base.remotable_classmethod
+    def get_uuids_by_host_and_node(cls, context, host, node):
+        """Return non-deleted instance UUIDs for the given host and node.
+
+        :param context: nova auth request context
+        :param host: Filter instances on this host.
+        :param node: Filter instances on this node.
+        :returns: list of non-deleted instance UUIDs on the given host and node
+        """
+        return cls._get_uuids_by_host_and_node(context, host, node)
+
     @base.remotable_classmethod
     def get_by_host_and_not_type(cls, context, host, type_id=None,
                                  expected_attrs=None):

nova/scheduler/client/report.py

@@ -2169,14 +2169,16 @@ def delete_resource_provider(self, context, compute_node, cascade=False):
             # Delete any allocations for this resource provider.
             # Since allocations are by consumer, we get the consumers on this
             # host, which are its instances.
-            # TODO(mriedem): Optimize this up by adding an
-            # InstanceList.get_uuids_by_host_and_node method.
-            # Pass expected_attrs=[] to avoid joining on extra columns we
-            # don't use.
-            instances = objects.InstanceList.get_by_host_and_node(
-                context, host, nodename, expected_attrs=[])
-            for instance in instances:
-                self.delete_allocation_for_instance(context, instance.uuid)
+            # NOTE(mriedem): This assumes the only allocations on this node
+            # are instances, but there could be migration consumers if the
+            # node is deleted during a migration or allocations from an
+            # evacuated host (bug 1829479). Obviously an admin shouldn't
+            # do that but...you know. I guess the provider deletion should fail
+            # in that case which is what we'd want to happen.
+            instance_uuids = objects.InstanceList.get_uuids_by_host_and_node(
+                context, host, nodename)
+            for instance_uuid in instance_uuids:
+                self.delete_allocation_for_instance(context, instance_uuid)
         try:
             self._delete_provider(rp_uuid, global_request_id=context.global_id)
         except (exception.ResourceProviderInUse,

nova/tests/unit/objects/test_objects.py

@@ -1084,7 +1084,7 @@ def obj_name(cls):
     'InstanceGroup': '1.11-852ac511d30913ee88f3c3a869a8f30a',
     'InstanceGroupList': '1.8-90f8f1a445552bb3bbc9fa1ae7da27d4',
     'InstanceInfoCache': '1.5-cd8b96fefe0fc8d4d337243ba0bf0e1e',
-    'InstanceList': '2.4-d2c5723da8c1d08e07cb00160edfd292',
+    'InstanceList': '2.5-43b5e7d8c4ebde52f2c2da22a1739e95',
     'InstanceMapping': '1.2-3bd375e65c8eb9c45498d2f87b882e03',
     'InstanceMappingList': '1.2-ee638619aa3d8a82a59c0c83bfa64d78',
     'InstanceNUMACell': '1.4-7c1eb9a198dee076b4de0840e45f4f55',

nova/tests/unit/scheduler/client/test_report.py

@@ -3188,21 +3188,18 @@ def test_instance_to_allocations_dict_zero_disk(self, mock_vbi):
                 "delete")
     @mock.patch("nova.scheduler.client.report.SchedulerReportClient."
                 "delete_allocation_for_instance")
-    @mock.patch("nova.objects.InstanceList.get_by_host_and_node")
+    @mock.patch("nova.objects.InstanceList.get_uuids_by_host_and_node")
     def test_delete_resource_provider_cascade(self, mock_by_host,
             mock_del_alloc, mock_delete):
         self.client._provider_tree.new_root(uuids.cn, uuids.cn, generation=1)
         cn = objects.ComputeNode(uuid=uuids.cn, host="fake_host",
                 hypervisor_hostname="fake_hostname", )
-        inst1 = objects.Instance(uuid=uuids.inst1)
-        inst2 = objects.Instance(uuid=uuids.inst2)
-        mock_by_host.return_value = objects.InstanceList(
-                objects=[inst1, inst2])
+        mock_by_host.return_value = [uuids.inst1, uuids.inst2]
         resp_mock = mock.Mock(status_code=204)
         mock_delete.return_value = resp_mock
         self.client.delete_resource_provider(self.context, cn, cascade=True)
         mock_by_host.assert_called_once_with(
-            self.context, cn.host, cn.hypervisor_hostname, expected_attrs=[])
+            self.context, cn.host, cn.hypervisor_hostname)
         self.assertEqual(2, mock_del_alloc.call_count)
         exp_url = "/resource_providers/%s" % uuids.cn
         mock_delete.assert_called_once_with(
@@ -3213,17 +3210,14 @@ def test_delete_resource_provider_cascade(self, mock_by_host,
                 "delete")
     @mock.patch("nova.scheduler.client.report.SchedulerReportClient."
                 "delete_allocation_for_instance")
-    @mock.patch("nova.objects.InstanceList.get_by_host_and_node")
+    @mock.patch("nova.objects.InstanceList.get_uuids_by_host_and_node")
     def test_delete_resource_provider_no_cascade(self, mock_by_host,
             mock_del_alloc, mock_delete):
         self.client._provider_tree.new_root(uuids.cn, uuids.cn, generation=1)
         self.client._association_refresh_time[uuids.cn] = mock.Mock()
         cn = objects.ComputeNode(uuid=uuids.cn, host="fake_host",
                 hypervisor_hostname="fake_hostname", )
-        inst1 = objects.Instance(uuid=uuids.inst1)
-        inst2 = objects.Instance(uuid=uuids.inst2)
-        mock_by_host.return_value = objects.InstanceList(
-                objects=[inst1, inst2])
+        mock_by_host.return_value = [uuids.inst1, uuids.inst2]
         resp_mock = mock.Mock(status_code=204)
         mock_delete.return_value = resp_mock
         self.client.delete_resource_provider(self.context, cn)