ashb commented on a change in pull request #12327:
URL: https://github.com/apache/airflow/pull/12327#discussion_r524024672
##########
File path: docs/concepts.rst
##########
@@ -793,6 +793,12 @@ to a class that is subclass of
:class:`~airflow.models.xcom.BaseXCom`. To alter
deserialization mechanism the custom class should override ``serialize_value``
and ``deserialize_value``
methods.
+It is also possible to override the ``orm_deserialize_value`` method which is
used for deserialization when
+recreating ORM XCom object. This happens every time we query the XCom table,
for example when we want to populate
+XCom list view in webserver. By default Airflow will use
``BaseXCom.orm_deserialize_value`` method which returns the
+value stored in Airflow database. In this way Airflow is avoiding unnecessary
requests that may occur in custom
+``deserialize`` methods of custom XCom backend.
Review comment:
```suggestion
value stored in Airflow database. If your XCom backend performs expensive
operations, or has
large values that aren't useful to show in such a view, override this method
to provide an
alternative representation.
```
##########
File path: docs/concepts.rst
##########
@@ -793,6 +793,12 @@ to a class that is subclass of
:class:`~airflow.models.xcom.BaseXCom`. To alter
deserialization mechanism the custom class should override ``serialize_value``
and ``deserialize_value``
methods.
+It is also possible to override the ``orm_deserialize_value`` method which is
used for deserialization when
+recreating ORM XCom object. This happens every time we query the XCom table,
for example when we want to populate
+XCom list view in webserver. By default Airflow will use
``BaseXCom.orm_deserialize_value`` method which returns the
+value stored in Airflow database. In this way Airflow is avoiding unnecessary
requests that may occur in custom
+``deserialize`` methods of custom XCom backend.
Review comment:
Just this @turbaszek Then :+1:
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