[OVN] Reduce the number of tables watched by MetadataProxyHandler

[Lucas Alvares Gomes]

Currently the MetadataProxyHandler is monitoring more tables than it's required to [0][1]. Analyzing the code, only the Port_Bindings and Datapath_Bindings table would be necessary.

The more tables it monitors, the bigger the burden is on OVSDB to keep all the in-memory replicas updated. In special, the Chassis table can generate a lot of events due to the agents health check mechanism in the OVN driver so, not monitoring it could prevent a lot of events from being set across the fabric.

[0] https://github.com/openstack/neutron/blob/6709cfcdfaf29a696cd83da23d1a30d6d0ae8045/neutron/agent/ovn/metadata/server.py#L59
[1] https://github.com/openstack/neutron/blob/6709cfcdfaf29a696cd83da23d1a30d6d0ae8045/neutron/agent/ovn/metadata/ovsdb.py#L34-L35

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/706499
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=b85c273639f30cbffd95bfb92564adc8fb586465
Submitter: Zuul
Branch: master

commit b85c273639f30cbffd95bfb92564adc8fb586465
Author: Lucas Alvares Gomes <email address hidden>
Date: Thu Feb 6 13:28:34 2020 +0000

    [OVN] Reduce the number of watched tables in MetadataProxyHandler

    This patch changes the SB IDL from the MetadataProxyHandler class to
    only watch the two required tables for it to function.

    The more tables it monitors, the bigger the burden is on the OVSDB to
    keep all the in-memory replicas updated. In special, the Chassis table
    can generate a lot of events due to the agents health check mechanism
    in the OVN driver so, removing it will prevent many events from being
    sent across the fabric.

    Closes-Bug: #1862648
    Change-Id: Ib4fb9b445ed7fe4bce7bc05ae1b8dca264324718
    Signed-off-by: Lucas Alvares Gomes <email address hidden>

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/neutron 16.0.0.0b1 development milestone.