iosif2 opened a new pull request, #53501:
URL: https://github.com/apache/airflow/pull/53501
## This PR addresses issues encountered when deleting dags via both the CLI
and the web UI.
### 1. ForeignKeyViolation on backfill table deletion
- Reproduction Steps: first backfill any DAG. Then, execute airflow dags
delete [dag_id].
- However executing the deletion twice as separate operations resolves the
issue and allows for successful deletion.
- Root Cause: This error occurs randomly due to how the delete_dag function
operates. I suspect that get_sqla_model_classes does not consistently return
models in the correct dependency order.
#### Command Line Output for this error:
```
root@f6650f6a4c58:/opt/airflow# airflow dags delete test_dag2
This will drop all existing records related to the specified DAG. Proceed?
(y/n)y
[2025-07-18T13:21:57.427+0000] {delete_dag.py:53} INFO - Deleting DAG:
test_dag2
Traceback (most recent call last):
File "/usr/local/lib/python3.10/site-packages/sqlalchemy/engine/base.py",
line 1910, in _execute_context
self.dialect.do_execute(
File
"/usr/local/lib/python3.10/site-packages/sqlalchemy/engine/default.py", line
736, in do_execute
cursor.execute(statement, parameters)
psycopg2.errors.ForeignKeyViolation: update or delete on table "backfill"
violates foreign key constraint "dag_run_backfill_id_fkey" on table "dag_run"
DETAIL: Key (id)=(2) is still referenced from table "dag_run".
The above exception was the direct cause of the following exception:
Traceback (most recent call last):
File "/usr/local/bin/airflow", line 10, in <module>
sys.exit(main())
File "/opt/airflow/airflow-core/src/airflow/__main__.py", line 55, in main
args.func(args)
File "/opt/airflow/airflow-core/src/airflow/cli/cli_config.py", line 48,
in command
return func(*args, **kwargs)
File "/opt/airflow/airflow-core/src/airflow/utils/cli.py", line 113, in
wrapper
return f(*args, **kwargs)
File
"/opt/airflow/airflow-core/src/airflow/utils/providers_configuration_loader.py",
line 54, in wrapped_function
return func(*args, **kwargs)
File "/opt/airflow/airflow-core/src/airflow/cli/commands/dag_command.py",
line 103, in dag_delete
message = api_client.delete_dag(dag_id=args.dag_id)
File "/opt/airflow/airflow-core/src/airflow/api/client/local_client.py",
line 74, in delete_dag
count = delete_dag.delete_dag(dag_id)
File "/opt/airflow/airflow-core/src/airflow/utils/session.py", line 100,
in wrapper
return func(*args, session=session, **kwargs)
File "/opt/airflow/airflow-core/src/airflow/api/common/delete_dag.py",
line 70, in delete_dag
count += session.execute(
File "/usr/local/lib/python3.10/site-packages/sqlalchemy/orm/session.py",
line 1717, in execute
result = conn._execute_20(statement, params or {}, execution_options)
File "/usr/local/lib/python3.10/site-packages/sqlalchemy/engine/base.py",
line 1710, in _execute_20
return meth(self, args_10style, kwargs_10style, execution_options)
File "/usr/local/lib/python3.10/site-packages/sqlalchemy/sql/elements.py",
line 334, in _execute_on_connection
return connection._execute_clauseelement(
File "/usr/local/lib/python3.10/site-packages/sqlalchemy/engine/base.py",
line 1577, in _execute_clauseelement
ret = self._execute_context(
File "/usr/local/lib/python3.10/site-packages/sqlalchemy/engine/base.py",
line 1953, in _execute_context
self._handle_dbapi_exception(
File "/usr/local/lib/python3.10/site-packages/sqlalchemy/engine/base.py",
line 2134, in _handle_dbapi_exception
util.raise_(
File "/usr/local/lib/python3.10/site-packages/sqlalchemy/util/compat.py",
line 211, in raise_
raise exception
File "/usr/local/lib/python3.10/site-packages/sqlalchemy/engine/base.py",
line 1910, in _execute_context
self.dialect.do_execute(
File
"/usr/local/lib/python3.10/site-packages/sqlalchemy/engine/default.py", line
736, in do_execute
cursor.execute(statement, parameters)
sqlalchemy.exc.IntegrityError: (psycopg2.errors.ForeignKeyViolation) update
or delete on table "backfill" violates foreign key constraint
"dag_run_backfill_id_fkey" on table "dag_run"
DETAIL: Key (id)=(2) is still referenced from table "dag_run".
[SQL: DELETE FROM backfill WHERE backfill.dag_id = %(dag_id_1)s RETURNING
backfill.id]
[parameters: {'dag_id_1': 'test_dag2'}]
(Background on this error at: https://sqlalche.me/e/14/gkpj)
```
### 2. ForeignKeyViolation on other tables (related to dag_version)
- Reproduction Steps: While I am not entirely certain how to consistently
reproduce this specific error, it appears alongside the backfill deletion error
described above.
- Root Cause: It suggests that deleting dag_version records is blocked
because they are still referenced by the task_instance table.
- Proposed Solution: I believe the RESTRICT ON DELETE behavior is
unnecessary for this table; thus, I have modified it to CASCADE to resolve this
issue.
#### Command Line Output for this error:
```
root@f6650f6a4c58:/opt/airflow/airflow-core/src/airflow# airflow dags delete
test_dag1
This will drop all existing records related to the specified DAG. Proceed?
(y/n)y
[2025-07-18T13:39:21.439+0000] {delete_dag.py:53} INFO - Deleting DAG:
test_dag1
Traceback (most recent call last):
File "/usr/local/lib/python3.10/site-packages/sqlalchemy/engine/base.py",
line 1910, in _execute_context
self.dialect.do_execute(
File
"/usr/local/lib/python3.10/site-packages/sqlalchemy/engine/default.py", line
736, in do_execute
cursor.execute(statement, parameters)
psycopg2.errors.ForeignKeyViolation: update or delete on table "dag_version"
violates foreign key constraint "task_instance_dag_version_id_fkey" on table
"task_instance"
DETAIL: Key (id)=(01981dc1-c244-7368-bd32-44242bc82280) is still referenced
from table "task_instance".
The above exception was the direct cause of the following exception:
Traceback (most recent call last):
File "/usr/local/bin/airflow", line 10, in <module>
sys.exit(main())
File "/opt/airflow/airflow-core/src/airflow/__main__.py", line 55, in main
args.func(args)
File "/opt/airflow/airflow-core/src/airflow/cli/cli_config.py", line 48,
in command
return func(*args, **kwargs)
File "/opt/airflow/airflow-core/src/airflow/utils/cli.py", line 113, in
wrapper
return f(*args, **kwargs)
File
"/opt/airflow/airflow-core/src/airflow/utils/providers_configuration_loader.py",
line 54, in wrapped_function
return func(*args, **kwargs)
File "/opt/airflow/airflow-core/src/airflow/cli/commands/dag_command.py",
line 103, in dag_delete
message = api_client.delete_dag(dag_id=args.dag_id)
File "/opt/airflow/airflow-core/src/airflow/api/client/local_client.py",
line 74, in delete_dag
count = delete_dag.delete_dag(dag_id)
File "/opt/airflow/airflow-core/src/airflow/utils/session.py", line 100,
in wrapper
return func(*args, session=session, **kwargs)
File "/opt/airflow/airflow-core/src/airflow/api/common/delete_dag.py",
line 70, in delete_dag
count += session.execute(
File "/usr/local/lib/python3.10/site-packages/sqlalchemy/orm/session.py",
line 1717, in execute
result = conn._execute_20(statement, params or {}, execution_options)
File "/usr/local/lib/python3.10/site-packages/sqlalchemy/engine/base.py",
line 1710, in _execute_20
return meth(self, args_10style, kwargs_10style, execution_options)
File "/usr/local/lib/python3.10/site-packages/sqlalchemy/sql/elements.py",
line 334, in _execute_on_connection
return connection._execute_clauseelement(
File "/usr/local/lib/python3.10/site-packages/sqlalchemy/engine/base.py",
line 1577, in _execute_clauseelement
ret = self._execute_context(
File "/usr/local/lib/python3.10/site-packages/sqlalchemy/engine/base.py",
line 1953, in _execute_context
self._handle_dbapi_exception(
File "/usr/local/lib/python3.10/site-packages/sqlalchemy/engine/base.py",
line 2134, in _handle_dbapi_exception
util.raise_(
File "/usr/local/lib/python3.10/site-packages/sqlalchemy/util/compat.py",
line 211, in raise_
raise exception
File "/usr/local/lib/python3.10/site-packages/sqlalchemy/engine/base.py",
line 1910, in _execute_context
self.dialect.do_execute(
File
"/usr/local/lib/python3.10/site-packages/sqlalchemy/engine/default.py", line
736, in do_execute
cursor.execute(statement, parameters)
sqlalchemy.exc.IntegrityError: (psycopg2.errors.ForeignKeyViolation) update
or delete on table "dag_version" violates foreign key constraint
"task_instance_dag_version_id_fkey" on table "task_instance"
DETAIL: Key (id)=(01981dc1-c244-7368-bd32-44242bc82280) is still referenced
from table "task_instance".
[SQL: DELETE FROM dag_version WHERE dag_version.dag_id = %(dag_id_1)s
RETURNING dag_version.id]
[parameters: {'dag_id_1': 'test_dag1'}]
(Background on this error at: https://sqlalche.me/e/14/gkpj)
```
<!--
Licensed to the Apache Software Foundation (ASF) under one
or more contributor license agreements. See the NOTICE file
distributed with this work for additional information
regarding copyright ownership. The ASF licenses this file
to you under the Apache License, Version 2.0 (the
"License"); you may not use this file except in compliance
with the License. You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing,
software distributed under the License is distributed on an
"AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
KIND, either express or implied. See the License for the
specific language governing permissions and limitations
under the License.
-->
<!--
Thank you for contributing! Please make sure that your code changes
are covered with tests. And in case of new features or big changes
remember to adjust the documentation.
Feel free to ping committers for the review!
In case of an existing issue, reference it using one of the following:
closes: #ISSUE
related: #ISSUE
How to write a good git commit message:
http://chris.beams.io/posts/git-commit/
-->
<!-- Please keep an empty line above the dashes. -->
---
**^ Add meaningful description above**
Read the **[Pull Request
Guidelines](https://github.com/apache/airflow/blob/main/contributing-docs/05_pull_requests.rst#pull-request-guidelines)**
for more information.
In case of fundamental code changes, an Airflow Improvement Proposal
([AIP](https://cwiki.apache.org/confluence/display/AIRFLOW/Airflow+Improvement+Proposals))
is needed.
In case of a new dependency, check compliance with the [ASF 3rd Party
License Policy](https://www.apache.org/legal/resolved.html#category-x).
In case of backwards incompatible changes please leave a note in a
newsfragment file, named `{pr_number}.significant.rst` or
`{issue_number}.significant.rst`, in
[airflow-core/newsfragments](https://github.com/apache/airflow/tree/main/airflow-core/newsfragments).
--
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.
To unsubscribe, e-mail: [email protected]
For queries about this service, please contact Infrastructure at:
[email protected]
