kaxil commented on a change in pull request #9851:
URL: https://github.com/apache/airflow/pull/9851#discussion_r455934821
##########
File path: airflow/models/serialized_dag.py
##########
@@ -233,3 +233,18 @@ def bulk_sync_to_db(dags: List[DAG], session: Session =
None):
min_update_interval=MIN_SERIALIZED_DAG_UPDATE_INTERVAL,
session=session
)
+
+ @classmethod
+ @provide_session
+ def get_last_updated_date(cls, dag_id: str, session: Session = None) ->
datetime:
+ """
+ Get the date when the Serialized DAG associated to DAG was last updated
+ in serialized_dag table
+
+ :param dag_id: DAG ID
+ :type dag_id: str
+ :param session: ORM Session
+ :type session: Session
+ """
+ result = session.query(cls.last_updated).filter(cls.dag_id ==
dag_id).one()
+ return result.last_updated
Review comment:
https://docs.sqlalchemy.org/en/13/orm/query.html?highlight=query%20get#sqlalchemy.orm.query.Query.get
>Query.get() is only used to return a single mapped instance, not multiple
instances or individual column constructs, and strictly on a single primary key
value. The originating Query must be constructed in this way, i.e. against a
single mapped entity, with no additional filtering criterion.
```
In [8]: with create_session() as session3:
...:
print(session3.query(SerializedDagModel.last_updated).get("example_xcom_args").scalar())
...:
---------------------------------------------------------------------------
InvalidRequestError Traceback (most recent call last)
<ipython-input-8-9a4a54c2d854> in <module>
1 with create_session() as session3:
----> 2
print(session3.query(SerializedDagModel.last_updated).get("example_xcom_args").scalar())
~/.virtualenvs/airflow_master/lib/python3.7/site-packages/sqlalchemy/orm/query.py
in get(self, ident)
1002
1003 """
-> 1004 return self._get_impl(ident, loading.load_on_pk_identity)
1005
1006 def _identity_lookup(
~/.virtualenvs/airflow_master/lib/python3.7/site-packages/sqlalchemy/orm/query.py
in _get_impl(self, primary_key_identity, db_load_fn, identity_token)
1063 primary_key_identity =
primary_key_identity.__composite_values__()
1064
-> 1065 mapper = self._only_full_mapper_zero("get")
1066
1067 is_dict = isinstance(primary_key_identity, dict)
~/.virtualenvs/airflow_master/lib/python3.7/site-packages/sqlalchemy/orm/query.py
in _only_full_mapper_zero(self, methname)
429 raise sa_exc.InvalidRequestError(
430 "%s() can only be used against "
--> 431 "a single mapped class." % methname
432 )
433 return self._primary_entity.entity_zero
InvalidRequestError: get() can only be used against a single mapped class.
```
Since it is just getting `last_updated` column it will be a relatively quick
operation
----------------------------------------------------------------
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
For queries about this service, please contact Infrastructure at:
[email protected]
