To avoid raise conditions on update :func:`viewflow.flow.flow_view` and :func:`viewflow.flow.flow_job` decoratos grabs process-instance wide locks and instansiate database transaction.
You could specify selected lock implementation in :attr:lock_impl of :class:`viewflow.base.Flow` class
.. autofunction:: viewflow.lock.no_lock
.. autofunction:: viewflow.lock.select_for_update_lock
.. autofunction:: viewflow.lock.cache_lock