Brian Haley 05fcfef6ce Change to use selectin for DB load strategy
During a mailing list discussion on some OOM issues neutron
has been seeing [0], Mike Bayer recommended we should change
from using subquery to selectin DB load strategy.

A full description of this strategy can be found here [1],
but in short:

- “subquery” loading incurs additional performance / complexity
  issues when used on a many-levels-deep eager load, as
  subqueries will be nested repeatedly.

- "The subqueryload() eager loader is mostly legacy at this
  point, superseded by selectinload()

- "The only scenario in which selectin eager loading is not
  feasible is when the model is using composite primary keys,
  and the backend database does not support tuples with IN,
  which currently includes SQL Server." So that does not
  apply to us.

The plan agreed to at the neutron drivers meeting [2] was to
make this change early in the cycle so we would be able to
see if there were any issues through the D cycle.

Added hacking checks so new code using subquery loads is
not added back.

[0] https://lists.openstack.org/archives/list/openstack-discuss@lists.openstack.org/thread/EHLQQXNG3NLLZYPDGG2ES3DINIJ7YT3N/
[1] https://docs.sqlalchemy.org/en/20/orm/queryguide/relationships.html#selectin-eager-loading
[2] https://meetings.opendev.org/meetings/neutron_drivers/2024/neutron_drivers.2024-05-31-14.00.log.html#l-67

Closes-bug: #2067770
Depends-on: https://review.opendev.org/c/openstack/neutron-lib/+/920936
Change-Id: I6e40a15284da392a3d48d45205a7a5770c14c297
2024-06-12 11:31:22 -04:00

134 lines
5.3 KiB
Python

# Copyright (c) 2013 OpenStack Foundation
# All Rights Reserved.
#
# 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 neutron_lib.api.definitions import portbindings
from neutron_lib import constants
from neutron_lib.db import model_base
import sqlalchemy as sa
from sqlalchemy import orm
from neutron.db.models import segment as segment_models
from neutron.db import models_v2
BINDING_PROFILE_LEN = 4095
class PortBinding(model_base.BASEV2):
"""Represent binding-related state of a port.
A port binding stores the port attributes required for the
portbindings extension, as well as internal ml2 state such as
which MechanismDriver and which segment are used by the port
binding.
"""
__tablename__ = 'ml2_port_bindings'
port_id = sa.Column(sa.String(36),
sa.ForeignKey('ports.id', ondelete="CASCADE"),
primary_key=True)
host = sa.Column(sa.String(255), nullable=False, default='',
server_default='', primary_key=True)
vnic_type = sa.Column(sa.String(64), nullable=False,
default=portbindings.VNIC_NORMAL,
server_default=portbindings.VNIC_NORMAL)
profile = sa.Column(sa.String(BINDING_PROFILE_LEN), nullable=False,
default='', server_default='')
vif_type = sa.Column(sa.String(64), nullable=False)
vif_details = sa.Column(sa.String(4095), nullable=False, default='',
server_default='')
status = sa.Column(sa.String(16), nullable=False,
default=constants.ACTIVE,
server_default=constants.ACTIVE)
# Add a relationship to the Port model in order to instruct SQLAlchemy to
# eagerly load port bindings
port = orm.relationship(
models_v2.Port,
load_on_pending=True,
backref=orm.backref("port_bindings",
lazy='joined',
cascade='delete'))
revises_on_change = ('port', )
class PortBindingLevel(model_base.BASEV2):
"""Represent each level of a port binding.
Stores information associated with each level of an established
port binding. Different levels might correspond to the host and
ToR switch, for instance.
"""
__tablename__ = 'ml2_port_binding_levels'
port_id = sa.Column(sa.String(36),
sa.ForeignKey('ports.id', ondelete="CASCADE"),
primary_key=True)
host = sa.Column(sa.String(255), nullable=False, primary_key=True)
level = sa.Column(sa.Integer, primary_key=True, autoincrement=False)
driver = sa.Column(sa.String(64))
segment_id = sa.Column(sa.String(36),
sa.ForeignKey('networksegments.id',
ondelete="SET NULL"))
# Add a relationship to the Port model in order to instruct SQLAlchemy to
# eagerly load port bindings
port = orm.relationship(
models_v2.Port,
load_on_pending=True,
backref=orm.backref("binding_levels", lazy='selectin',
cascade='delete'))
segment = orm.relationship(
segment_models.NetworkSegment,
load_on_pending=True)
revises_on_change = ('port', )
class DistributedPortBinding(model_base.BASEV2):
"""Represent binding-related state of a Distributed Router(DVR, HA) port.
Port binding for all the ports associated to a Distributed router(DVR, HA)
identified by router_id. Currently DEVICE_OWNER_ROUTER_SNAT(DVR+HA router),
DEVICE_OWNER_DVR_INTERFACE, DEVICE_OWNER_HA_REPLICATED_INT are distributed
router ports.
"""
__tablename__ = 'ml2_distributed_port_bindings'
port_id = sa.Column(sa.String(36),
sa.ForeignKey('ports.id', ondelete="CASCADE"),
primary_key=True)
host = sa.Column(sa.String(255), nullable=False, primary_key=True)
router_id = sa.Column(sa.String(36), nullable=True)
vif_type = sa.Column(sa.String(64), nullable=False)
vif_details = sa.Column(sa.String(4095), nullable=False, default='',
server_default='')
vnic_type = sa.Column(sa.String(64), nullable=False,
default=portbindings.VNIC_NORMAL,
server_default=portbindings.VNIC_NORMAL)
profile = sa.Column(sa.String(BINDING_PROFILE_LEN), nullable=False,
default='', server_default='')
status = sa.Column(sa.String(16), nullable=False)
# Add a relationship to the Port model in order to instruct SQLAlchemy to
# eagerly load port bindings
port = orm.relationship(
models_v2.Port,
load_on_pending=True,
backref=orm.backref("distributed_port_binding",
cascade='delete'))
revises_on_change = ('port', )