diff options
Diffstat (limited to 'oslo_db/sqlalchemy/utils.py')
| -rw-r--r-- | oslo_db/sqlalchemy/utils.py | 31 |
1 files changed, 25 insertions, 6 deletions
diff --git a/oslo_db/sqlalchemy/utils.py b/oslo_db/sqlalchemy/utils.py index b9996d4..f5dda31 100644 --- a/oslo_db/sqlalchemy/utils.py +++ b/oslo_db/sqlalchemy/utils.py @@ -31,6 +31,7 @@ from sqlalchemy import Column from sqlalchemy.engine import Connectable from sqlalchemy.engine import reflection from sqlalchemy.engine import url as sa_url +from sqlalchemy import exc from sqlalchemy import func from sqlalchemy import Index from sqlalchemy import inspect @@ -71,16 +72,26 @@ def get_unique_keys(model): :param model: the ORM model class :rtype: list of sets of strings - :return: unique model keys + :return: unique model keys or None if unable to find them """ + + try: + mapper = inspect(model) + except exc.NoInspectionAvailable: + return None + else: + table = mapper.mapped_table + if table is None: + return None + # extract result from cache if present - info = model.__table__.info + info = table.info if 'oslodb_unique_keys' in info: return info['oslodb_unique_keys'] res = [] try: - constraints = model.__table__.constraints + constraints = table.constraints except AttributeError: constraints = [] for constraint in constraints: @@ -89,7 +100,7 @@ def get_unique_keys(model): sqlalchemy.PrimaryKeyConstraint)): res.append({c.name for c in constraint.columns}) try: - indexes = model.__table__.indexes + indexes = table.indexes except AttributeError: indexes = [] for index in indexes: @@ -101,8 +112,16 @@ def get_unique_keys(model): def _stable_sorting_order(model, sort_keys): + """Check whetever the sorting order is stable. + + :return: True if it is stable, False if it's not, None if it's impossible + to determine. + """ + keys = get_unique_keys(model) + if keys is None: + return None sort_keys_set = set(sort_keys) - for unique_keys in get_unique_keys(model): + for unique_keys in keys: if unique_keys.issubset(sort_keys_set): return True return False @@ -142,7 +161,7 @@ def paginate_query(query, model, limit, sort_keys, marker=None, :rtype: sqlalchemy.orm.query.Query :return: The query with sorting/pagination added. """ - if not _stable_sorting_order(model, sort_keys): + if _stable_sorting_order(model, sort_keys) is False: LOG.warning(_LW('Unique keys not in sort_keys. ' 'The sorting order may be unstable.')) |