From ebe9e046c674c6c7aa72a58b38104894e90bbafe Mon Sep 17 00:00:00 2001
From: Rodolfo Alonso Hernandez <ralonsoh@redhat.com>
Date: Fri, 7 Jan 2022 15:50:19 +0000
Subject: [PATCH] Create an index for "agents.host" column

This index improves any query filtering by agent host name.

Closes-Bug: #1955639
Change-Id: Ice4fd6319d4c7d403bdc74a25e3d7cac31fb4c9f
---
 .../alembic_migrations/versions/EXPAND_HEAD   |  2 +-
 .../cd9ef14ccf87_add_index_to_agents_host.py  | 37 +++++++++++++++++++
 neutron/db/models/agent.py                    |  2 +-
 3 files changed, 39 insertions(+), 2 deletions(-)
 create mode 100644 neutron/db/migration/alembic_migrations/versions/yoga/expand/cd9ef14ccf87_add_index_to_agents_host.py

diff --git a/neutron/db/migration/alembic_migrations/versions/EXPAND_HEAD b/neutron/db/migration/alembic_migrations/versions/EXPAND_HEAD
index 8bdbec889ef..ac6fb48e5d9 100644
--- a/neutron/db/migration/alembic_migrations/versions/EXPAND_HEAD
+++ b/neutron/db/migration/alembic_migrations/versions/EXPAND_HEAD
@@ -1 +1 @@
-8160f7a9cebb
+cd9ef14ccf87
diff --git a/neutron/db/migration/alembic_migrations/versions/yoga/expand/cd9ef14ccf87_add_index_to_agents_host.py b/neutron/db/migration/alembic_migrations/versions/yoga/expand/cd9ef14ccf87_add_index_to_agents_host.py
new file mode 100644
index 00000000000..75d4f743995
--- /dev/null
+++ b/neutron/db/migration/alembic_migrations/versions/yoga/expand/cd9ef14ccf87_add_index_to_agents_host.py
@@ -0,0 +1,37 @@
+# Copyright 2022 OpenStack Foundation
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+#
+
+from alembic import op
+
+
+"""add index to agents host
+
+Revision ID: cd9ef14ccf87
+Revises: 8160f7a9cebb
+Create Date: 2022-01-07 15:45:33.319170
+
+"""
+
+# revision identifiers, used by Alembic.
+revision = 'cd9ef14ccf87'
+down_revision = '8160f7a9cebb'
+
+
+TABLE = 'agents'
+COLUMN = 'host'
+
+
+def upgrade():
+    op.create_index(op.f('ix_' + TABLE + '_' + COLUMN), TABLE, [COLUMN])
diff --git a/neutron/db/models/agent.py b/neutron/db/models/agent.py
index d6c0473d543..0c2ab8cf4b9 100644
--- a/neutron/db/models/agent.py
+++ b/neutron/db/models/agent.py
@@ -33,7 +33,7 @@ class Agent(model_base.BASEV2, model_base.HasId):
     # TOPIC is a fanout exchange topic
     topic = sa.Column(sa.String(255), nullable=False)
     # TOPIC.host is a target topic
-    host = sa.Column(sa.String(255), nullable=False)
+    host = sa.Column(sa.String(255), nullable=False, index=True)
     availability_zone = sa.Column(sa.String(255))
     admin_state_up = sa.Column(sa.Boolean, default=True,
                                server_default=sql.true(), nullable=False)