when I do a pdb inside a filter in scheduler, it is dropping inside the pdb shell. So far so good.

But when I execute these statements inside it as shown below, the buildrequest function get_by_instance_uuid is failing to return any db object:

----------

class ComputeFilter(filters.BaseHostFilter):
    """Filter on active Compute nodes."""

    RUN_ON_REBUILD = False

    def __init__(self):
        self.servicegroup_api = servicegroup.API()

    # Host state does not change within a request
    run_filter_once_per_request = True

    def host_passes(self, host_state, spec_obj):
        """Returns True for only active compute nodes."""

        breakpoint().   <--------------
        service = host_state.service
        if service['disabled']:
            LOG.debug("%(host_state)s is disabled, reason: %(reason)s",
                      {'host_state': host_state,
                       'reason': service.get('disabled_reason')})
            return False
        else:
            if not self.servicegroup_api.service_is_up(service):
                LOG.warning("%(host_state)s has not been heard from in a "
                            "while", {'host_state': host_state})
                return False
        return True

-----

at the above breakpoint, it is dropping into the pdb shell.
(pdb) from nova import objects as object

(pdb) object.BuildRequest.get_by_instance_uuid(spec_obj._context, instance_uuid=spec_obj.instance_uuid))

----

But if I place the above buildrequest inside the above same filter and run it normally without breakpoint(), it is working fine.  So, why am I not able to do it manually while in pdb, and succeed when done normally ?