Error during ComputeManager._poll_bandwidth_usage

[Armando Migliaccio]

I see this stacktrace in the compute log.

Feb 16 13:09:52 8E-B1-AF-C3-4C-C9 nova-compute ERROR Error during ComputeManager._poll_bandwidth_usage: Object '<BandwidthUsage at 0xa42dccc>' is already attached to session '170412556' (this is '167661484')
(nova.manager): TRACE: Traceback (most recent call last):
(nova.manager): TRACE: File "/usr/lib/python2.6/site-packages/nova/manager.py", line 155, in periodic_tasks
(nova.manager): TRACE: task(self, context)
(nova.manager): TRACE: File "/usr/lib/python2.6/site-packages/nova/compute/manager.py", line 2088, in _poll_bandwidth_usage
(nova.manager): TRACE: usage['bw_in'], usage['bw_out'])
(nova.manager): TRACE: File "/usr/lib/python2.6/site-packages/nova/db/api.py", line 1561, in bw_usage_update
(nova.manager): TRACE: bw_in, bw_out)
(nova.manager): TRACE: File "/usr/lib/python2.6/site-packages/nova/db/sqlalchemy/api.py", line 119, in wrapper
(nova.manager): TRACE: return f(*args, **kwargs)
(nova.manager): TRACE: File "/usr/lib/python2.6/site-packages/nova/db/sqlalchemy/api.py", line 3737, in bw_usage_update
(nova.manager): TRACE: bwusage.save(session=session)
(nova.manager): TRACE: File "/usr/lib/python2.6/site-packages/nova/db/sqlalchemy/models.py", line 56, in save
(nova.manager): TRACE: session.add(self)
(nova.manager): TRACE: File "/usr/lib/python2.6/site-packages/SQLAlchemy-0.6.5-py2.6.egg/sqlalchemy/orm/session.py", line 1101, in add
(nova.manager): TRACE: self._save_or_update_state(state)
(nova.manager): TRACE: File "/usr/lib/python2.6/site-packages/SQLAlchemy-0.6.5-py2.6.egg/sqlalchemy/orm/session.py", line 1110, in _save_or_update_state
(nova.manager): TRACE: self._save_or_update_impl(state)
(nova.manager): TRACE: File "/usr/lib/python2.6/site-packages/SQLAlchemy-0.6.5-py2.6.egg/sqlalchemy/orm/session.py", line 1307, in _save_or_update_impl
(nova.manager): TRACE: self._update_impl(state)
(nova.manager): TRACE: File "/usr/lib/python2.6/site-packages/SQLAlchemy-0.6.5-py2.6.egg/sqlalchemy/orm/session.py", line 1299, in _update_impl
(nova.manager): TRACE: self._attach(state)
(nova.manager): TRACE: File "/usr/lib/python2.6/site-packages/SQLAlchemy-0.6.5-py2.6.egg/sqlalchemy/orm/session.py", line 1333, in _attach
(nova.manager): TRACE: state.session_id, self.hash_key))
(nova.manager): TRACE: InvalidRequestError: Object '<BandwidthUsage at 0xa42dccc>' is already attached to session '170412556' (this is '167661484')
(nova.manager): TRACE:

It does not happen every time, I am using xenapi as backend driver. This happens on Essex trunk (or very close to it).

I'll try to dig out more info, but any further insight would be helpful.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/4271

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/4271
Committed: http://github.com/openstack/nova/commit/57da3b12b14ce7676b51904c97a4685692d7b5cc
Submitter: Jenkins
Branch: master

commit 57da3b12b14ce7676b51904c97a4685692d7b5cc
Author: Armando Migliaccio <email address hidden>
Date: Fri Feb 17 11:44:27 2012 +0000

    bug 933620: Error during ComputeManager._poll_bandwidth_usage

    add missing session to model query.

    Change-Id: I3cb8ebcff1fd286ef198f33514d4ce3d884c5921