DBDeadlock while deleting fixed_ip from port

[Ilya Shakhat]

Symptoms: subnet delete operation failed with HTTP 500 error. Log contains message "Exception deleting fixed_ip from port 436c7a3d-97ba-4455-892c-435b72c06940" followed by traceback

VERSION:
  feature_groups:
    - mirantis
  production: "docker"
  release: "6.1"
  openstack_version: "2014.2-6.1"
  api: "1.0"
  build_number: "323"
  build_id: "2015-04-20_07-52-58"
  nailgun_sha: "5a4556ea0cf943edffa33788994b7fb7abe150b3"
  python-fuelclient_sha: "b4f1ddffd5263489090b65e662173e9e11aafd94"
  astute_sha: "bf1751a4fe0d912325e3b4af629126a59c1b2b51"
  fuellib_sha: "36f30ae7f19092a61eebb0522ca20d27468b4cbf"
  ostf_sha: "4bab9b975ace8d9a305d6e0f112b734de587f847"
  fuelmain_sha: "991fa8feca4afcf05ce85a1e7ebd7c7503b3f212"

ENVIRONMENT:
KVM, Ubuntu, Neutron-vlan,
Controllers: 2 + 1 (Ceph)
Computes: 1 + 1 (Ceph)

Steps to repro:
1. Use mos-tempest-runner toolkit
2. run_tests tempest.api.network.test_ports

[Ilya Shakhat (shakhat)]

Stacktrace (neutron-server.log):
2015-04-30T14:06:25.975776+00:00 err: 2015-04-30 14:06:25.971 18638 ERROR neutron.plugins.ml2.plugin [req-ae3d6cdc-f518-4f92-819d-8b71761fe382 None] Exception deleting fixed_ip from port 436c7a3d-97ba-445
5-892c-435b72c06940
2015-04-30 14:06:25.971 18638 TRACE neutron.plugins.ml2.plugin Traceback (most recent call last):
2015-04-30 14:06:25.971 18638 TRACE neutron.plugins.ml2.plugin File "/usr/lib/python2.7/dist-packages/neutron/plugins/ml2/plugin.py", line 787, in delete_subnet
2015-04-30 14:06:25.971 18638 TRACE neutron.plugins.ml2.plugin self.update_port(context, a.port_id, data)
2015-04-30 14:06:25.971 18638 TRACE neutron.plugins.ml2.plugin File "/usr/lib/python2.7/dist-packages/neutron/plugins/ml2/plugin.py", line 869, in update_port
2015-04-30 14:06:25.971 18638 TRACE neutron.plugins.ml2.plugin port)
2015-04-30 14:06:25.971 18638 TRACE neutron.plugins.ml2.plugin File "/usr/lib/python2.7/dist-packages/neutron/db/db_base_plugin_v2.py", line 1375, in update_port
2015-04-30 14:06:25.971 18638 TRACE neutron.plugins.ml2.plugin port = self._get_port(context, id)
2015-04-30 14:06:25.971 18638 TRACE neutron.plugins.ml2.plugin File "/usr/lib/python2.7/dist-packages/neutron/db/db_base_plugin_v2.py", line 106, in _get_port
2015-04-30 14:06:25.971 18638 TRACE neutron.plugins.ml2.plugin port = self._get_by_id(context, models_v2.Port, id)
2015-04-30 14:06:25.971 18638 TRACE neutron.plugins.ml2.plugin File "/usr/lib/python2.7/dist-packages/neutron/db/common_db_mixin.py", line 125, in _get_by_id
2015-04-30 14:06:25.971 18638 TRACE neutron.plugins.ml2.plugin return query.filter(model.id == id).one()
2015-04-30 14:06:25.971 18638 TRACE neutron.plugins.ml2.plugin File "/usr/lib/python2.7/dist-packages/sqlalchemy/orm/query.py", line 2369, in one
2015-04-30 14:06:25.971 18638 TRACE neutron.plugins.ml2.plugin ret = list(self)
2015-04-30 14:06:25.971 18638 TRACE neutron.plugins.ml2.plugin File "/usr/lib/python2.7/dist-packages/sqlalchemy/orm/query.py", line 2412, in __iter__
2015-04-30 14:06:25.971 18638 TRACE neutron.plugins.ml2.plugin return self._execute_and_instances(context)
2015-04-30 14:06:25.971 18638 TRACE neutron.plugins.ml2.plugin File "/usr/lib/python2.7/dist-packages/sqlalchemy/orm/query.py", line 2427, in _execute_and_instances
2015-04-30 14:06:25.971 18638 TRACE neutron.plugins.ml2.plugin result = conn.execute(querycontext.statement, self._params)
2015-04-30 14:06:25.971 18638 TRACE neutron.plugins.ml2.plugin File "/usr/lib/python2.7/dist-packages/sqlalchemy/engine/base.py", line 729, in execute
2015-04-30 14:06:25.971 18638 TRACE neutron.plugins.ml2.plugin return meth(self, multiparams, params)
2015-04-30 14:06:25.971 18638 TRACE neutron.plugins.ml2.plugin File "/usr/lib/python2.7/dist-packages/sqlalchemy/sql/elements.py", line 321, in _execute_on_connection
2015-04-30 14:06:25.971 18638 TRACE neutron.plugins.ml2.plugin return connection._execute_clauseelement(self, multiparams, params)
2015-04-30 14:06:25.971 18638 TRACE neutron.plugins.ml2.plugin File "/usr/lib/python2.7/dist-packages/sqlalchemy/engine/base.py", line 826, in _execute_clauseelement
...

[Alexander Ignatov (aignatov)]

Since issue was not reproduced as per last comment and submitter doesn't care moving this issue to Invalid.
Also please see this issue in Incomplete more than month.