<div dir="ltr"><p class="">Hi All,</p>

<p class=""> </p>

<p class="">In my mechanism driver, I am reading/writing into sql db
in a fixed interval looping call. Sometimes I get the following error when I
stop and start neutron server</p>

<p class="">InvalidRequestError: This session is in 'prepared' state;
no further SQL can be emitted within this transaction.</p>

<p class=""> </p>

<p class="">I am using context.session.query() for add, delete,
update and get. Please help me if any one resolved an issue like this.</p>

<p class=""> </p>

<p class="">Full trace is as follows:</p>

<p class="">2016-01-06 15:33:21.799 [01;31mERROR
neutron.plugins.ml2.managers [[01;36mreq-d940a1b6-253a-43d2-b5ff-6c784c8a520f [00;36madmin
83b5358da62a407f88155f447966356f[01;31m] [01;35m[01;31mMechanism driver 'hp'
failed in create_port_precommit[00m</p>

<p class="">[01;31m2016-01-06 15:33:21.799 TRACE
neutron.plugins.ml2.managers [01;35m[00mTraceback (most recent call last):</p>

<p class="">[01;31m2016-01-06 15:33:21.799 TRACE
neutron.plugins.ml2.managers [01;35m[00m 
File "/opt/stack/neutron/neutron/plugins/ml2/managers.py",
line 394, in _call_on_drivers</p>

<p class="">[01;31m2016-01-06 15:33:21.799 TRACE
neutron.plugins.ml2.managers [01;35m[00m   
getattr(driver.obj, method_name)(context)</p>

<p class="">[01;31m2016-01-06 15:33:21.799 TRACE
neutron.plugins.ml2.managers [01;35m[00m 
File
"/usr/local/lib/python2.7/dist-packages/baremetal_network_provisioning/ml2/mechanism_hp.py",
line 67, in create_port_precommit</p>

<p class="">[01;31m2016-01-06 15:33:21.799 TRACE
neutron.plugins.ml2.managers [01;35m[00m   
raise e</p>

<p class="">[01;31m2016-01-06 15:33:21.799 TRACE
neutron.plugins.ml2.managers [01;35m[00mInvalidRequestError: This session is in
'prepared' state; no further SQL can be emitted within this transaction.</p>

<p class="">[01;31m2016-01-06 15:33:21.799 TRACE
neutron.plugins.ml2.managers [01;35m[00m</p>

<p class="">2016-01-06 15:33:21.901 [01;31mERROR
neutron.api.v2.resource [[01;36mreq-d940a1b6-253a-43d2-b5ff-6c784c8a520f [00;36madmin
83b5358da62a407f88155f447966356f[01;31m] [01;35m[01;31mcreate failed[00m</p>

<p class="">[01;31m2016-01-06 15:33:21.901 TRACE
neutron.api.v2.resource [01;35m[00mTraceback (most recent call last):</p>

<p class="">[01;31m2016-01-06 15:33:21.901 TRACE
neutron.api.v2.resource [01;35m[00m  File
"/opt/stack/neutron/neutron/api/v2/resource.py", line 83, in resource</p>

<p class="">[01;31m2016-01-06 15:33:21.901 TRACE
neutron.api.v2.resource [01;35m[00m   
result = method(request=request, **args)</p>

<p class="">[01;31m2016-01-06 15:33:21.901 TRACE
neutron.api.v2.resource [01;35m[00m  File
"/usr/local/lib/python2.7/dist-packages/oslo_db/api.py", line 146, in
wrapper</p>

<p class="">[01;31m2016-01-06 15:33:21.901 TRACE
neutron.api.v2.resource [01;35m[00m   
ectxt.value = e.inner_exc</p>

<p class="">[01;31m2016-01-06 15:33:21.901 TRACE
neutron.api.v2.resource [01;35m[00m  File
"/usr/local/lib/python2.7/dist-packages/oslo_utils/excutils.py", line
195, in __exit__</p>

<p class="">[01;31m2016-01-06 15:33:21.901 TRACE
neutron.api.v2.resource [01;35m[00m   
six.reraise(self.type_, self.value, self.tb)</p>

<p class="">[01;31m2016-01-06 15:33:21.901 TRACE
neutron.api.v2.resource [01;35m[00m  File
"/usr/local/lib/python2.7/dist-packages/oslo_db/api.py", line 136, in
wrapper</p>

<p class="">[01;31m2016-01-06 15:33:21.901 TRACE
neutron.api.v2.resource [01;35m[00m   
return f(*args, **kwargs)</p>

<p class="">[01;31m2016-01-06 15:33:21.901 TRACE
neutron.api.v2.resource [01;35m[00m  File
"/opt/stack/neutron/neutron/api/v2/base.py", line 516, in create</p>

<p class="">[01;31m2016-01-06 15:33:21.901 TRACE
neutron.api.v2.resource [01;35m[00m   
obj = do_create(body)</p>

<p class="">[01;31m2016-01-06 15:33:21.901 TRACE
neutron.api.v2.resource [01;35m[00m  File
"/opt/stack/neutron/neutron/api/v2/base.py", line 498, in do_create</p>

<p class="">[01;31m2016-01-06 15:33:21.901 TRACE
neutron.api.v2.resource [01;35m[00m   
request.context, reservation.reservation_id)</p>

<p class="">[01;31m2016-01-06 15:33:21.901 TRACE
neutron.api.v2.resource [01;35m[00m  File
"/usr/local/lib/python2.7/dist-packages/oslo_utils/excutils.py", line
195, in __exit__</p>

<p class="">[01;31m2016-01-06 15:33:21.901 TRACE
neutron.api.v2.resource [01;35m[00m   
six.reraise(self.type_, self.value, self.tb)</p>

<p class="">[01;31m2016-01-06 15:33:21.901 TRACE
neutron.api.v2.resource [01;35m[00m  File
"/opt/stack/neutron/neutron/api/v2/base.py", line 491, in do_create</p>

<p class="">[01;31m2016-01-06 15:33:21.901 TRACE
neutron.api.v2.resource [01;35m[00m   
return obj_creator(request.context, **kwargs)</p>

<p class="">[01;31m2016-01-06 15:33:21.901 TRACE
neutron.api.v2.resource [01;35m[00m  File
"/usr/local/lib/python2.7/dist-packages/oslo_db/api.py", line 146, in
wrapper</p>

<p class="">[01;31m2016-01-06 15:33:21.901 TRACE
neutron.api.v2.resource [01;35m[00m   
ectxt.value = e.inner_exc</p>

<p class="">[01;31m2016-01-06 15:33:21.901 TRACE
neutron.api.v2.resource [01;35m[00m  File
"/usr/local/lib/python2.7/dist-packages/oslo_utils/excutils.py", line
195, in __exit__</p>

<p class="">[01;31m2016-01-06 15:33:21.901 TRACE
neutron.api.v2.resource [01;35m[00m   
six.reraise(self.type_, self.value, self.tb)</p>

<p class="">[01;31m2016-01-06 15:33:21.901 TRACE
neutron.api.v2.resource [01;35m[00m  File
"/usr/local/lib/python2.7/dist-packages/oslo_db/api.py", line 136, in
wrapper</p>

<p class="">[01;31m2016-01-06 15:33:21.901 TRACE
neutron.api.v2.resource [01;35m[00m   
return f(*args, **kwargs)</p>

<p class="">[01;31m2016-01-06 15:33:21.901 TRACE
neutron.api.v2.resource [01;35m[00m  File
"/opt/stack/neutron/neutron/plugins/ml2/plugin.py", line 1040, in
create_port</p>

<p class="">[01;31m2016-01-06 15:33:21.901 TRACE
neutron.api.v2.resource [01;35m[00m   
result, mech_context = self._create_port_db(context, port)</p>

<p class="">[01;31m2016-01-06 15:33:21.901 TRACE neutron.api.v2.resource
[01;35m[00m  File
"/opt/stack/neutron/neutron/plugins/ml2/plugin.py", line 1032, in
_create_port_db</p>

<p class="">[01;31m2016-01-06 15:33:21.901 TRACE
neutron.api.v2.resource [01;35m[00m   
self.mechanism_manager.create_port_precommit(mech_context)</p>

<p class="">[01;31m2016-01-06 15:33:21.901 TRACE
neutron.api.v2.resource [01;35m[00m  File
"/opt/stack/neutron/neutron/plugins/ml2/managers.py", line 590, in
create_port_precommit</p>

<p class="">[01;31m2016-01-06 15:33:21.901 TRACE
neutron.api.v2.resource [01;35m[00m   
self._call_on_drivers("create_port_precommit", context)</p>

<p class="">[01;31m2016-01-06 15:33:21.901 TRACE
neutron.api.v2.resource [01;35m[00m  File
"/opt/stack/neutron/neutron/plugins/ml2/managers.py", line 405, in
_call_on_drivers</p>

<p class="">[01;31m2016-01-06 15:33:21.901 TRACE neutron.api.v2.resource
[01;35m[00m    method=method_name</p>

<p class="">[01;31m2016-01-06 15:33:21.901 TRACE
neutron.api.v2.resource [01;35m[00mMechanismDriverError: create_port_precommit
failed.</p>

<p class="">[01;31m2016-01-06 15:33:21.901 TRACE
neutron.api.v2.resource [01;35m[00m</p>

<p class=""> </p>

<p class="">Regards,</p>

<p class="">Koteswar</p></div>