openstack/neutron
Code Issues Proposed changes

Merge "Protect against non-determinstic sort" into stable/newton

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Jenkins 2017-03-28 01:05:20 +00:00 committed by Gerrit Code Review
commit f7ad320603
1 changed files with 27 additions and 0 deletions
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27
neutron/db/common_db_mixin.py
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@ -287,12 +287,39 @@ class CommonDbMixin(object):
if sorts:
sort_keys = db_utils.get_and_validate_sort_keys(sorts, model)
sort_dirs = db_utils.get_sort_dirs(sorts, page_reverse)
if limit:
# we always want deterministic results for limit subqueries
# so add unique keys to limit queries when present.
# (http://docs.sqlalchemy.org/en/latest/orm/
# loading_relationships.html#subqueryload-ordering)
# (http://docs.sqlalchemy.org/en/latest/faq/
# ormconfiguration.html#faq-subqueryload-limit-sort)
for k in self._unique_keys(model, marker_obj):
if k not in sort_keys:
sort_keys.append(k)
sort_dirs.append('asc')
collection = sa_utils.paginate_query(collection, model, limit,
marker=marker_obj,
sort_keys=sort_keys,
sort_dirs=sort_dirs)
return collection
def _unique_keys(self, model, marker_obj):
# just grab first set of unique keys and use them.
# if model has no unqiue sets, 'paginate_query' will
# warn if sorting is unstable
uk_sets = sa_utils._get_unique_keys(model)
for kset in uk_sets:
for k in kset:
if marker_obj and isinstance(getattr(marker_obj, k), bool):
# TODO(kevinbenton): workaround for bug/1656947.
# we can't use boolean cols until that bug is fixed. return
# first entry in uk_sets once that bug is resolved
break
else:
return kset
return []
def _get_collection(self, context, model, dict_func, filters=None,
fields=None, sorts=None, limit=None, marker_obj=None,
page_reverse=False):