Change TaskInstance and TaskReschedule PK from execution_date to run_…

…id (#17719) Since TaskReschedule had an existing FK to TaskInstance we had to move change both of these at the same time. This puts an explicit FK constraint between TaskInstance and DagRun, meaning that we can remove a lot of "find TIs without DagRun" code in the scheduler too, as that is no longer a possible situation. Since there is now an explicit foreign key between TaskInstance and DagRun, we can remove a lot of the "cleanup" code in the scheduler that was dealing with this. This change was made as part of AIP-39 Co-authored-by: Tzu-ping Chung <[email protected]>
apache · Sep 7, 2021 · 944dcfb · 944dcfb
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diff --git a/UPDATING.md b/UPDATING.md
@@ -228,6 +228,16 @@ Now that the DAG parser syncs DAG permissions there is no longer a need for manu
 
 In addition, the `/refresh` and `/refresh_all` webserver endpoints have also been removed.
 
+### TaskInstances now *require* a DagRun
+
+Under normal operation every TaskInstance row in the database would have DagRun row too, but it was possible to manually delete the DagRun and Airflow would still schedule the TaskInstances.
+
+In Airflow 2.2 we have changed this and now there is a database-level foreign key constraint ensuring that every TaskInstance has a DagRun row.
+
+Before updating to this 2.2 release you will have to manually resolve any inconsistencies (add back DagRun rows, or delete TaskInstances) if you have any "dangling" TaskInstance" rows.
+
+As part of this change the `clean_tis_without_dagrun_interval` config option under `[scheduler]` section has been removed and has no effect.
+
 ## Airflow 2.1.3
 
 No breaking changes.

diff --git a/airflow/api/common/experimental/mark_tasks.py b/airflow/api/common/experimental/mark_tasks.py
@@ -21,6 +21,7 @@
 from typing import Iterable
 
 from sqlalchemy import or_
+from sqlalchemy.orm import contains_eager
 
 from airflow.models.baseoperator import BaseOperator
 from airflow.models.dagrun import DagRun
@@ -148,12 +149,14 @@ def get_all_dag_task_query(dag, session, state, task_ids, confirmed_dates):
  """Get all tasks of the main dag that will be affected by a state change"""
  qry_dag = (
  session.query(TaskInstance)
+ .join(TaskInstance.dag_run)
  .filter(
  TaskInstance.dag_id == dag.dag_id,
- TaskInstance.execution_date.in_(confirmed_dates),
+ DagRun.execution_date.in_(confirmed_dates),
  TaskInstance.task_id.in_(task_ids),
  )
  .filter(or_(TaskInstance.state.is_(None), TaskInstance.state != state))
+ .options(contains_eager(TaskInstance.dag_run))
  )
  return qry_dag
 

diff --git a/airflow/api_connexion/endpoints/log_endpoint.py b/airflow/api_connexion/endpoints/log_endpoint.py
@@ -18,12 +18,13 @@
 from flask import Response, current_app, request
 from itsdangerous.exc import BadSignature
 from itsdangerous.url_safe import URLSafeSerializer
+from sqlalchemy.orm import eagerload
 
 from airflow.api_connexion import security
 from airflow.api_connexion.exceptions import BadRequest, NotFound
 from airflow.api_connexion.schemas.log_schema import LogResponseObject, logs_schema
 from airflow.exceptions import TaskNotFound
-from airflow.models import DagRun
+from airflow.models import TaskInstance
 from airflow.security import permissions
 from airflow.utils.log.log_reader import TaskLogReader
 from airflow.utils.session import provide_session
@@ -60,15 +61,16 @@ def get_log(session, dag_id, dag_run_id, task_id, task_try_number, full_content=
  if not task_log_reader.supports_read:
  raise BadRequest("Task log handler does not support read logs.")
 
- query = session.query(DagRun).filter(DagRun.dag_id == dag_id)
- dag_run = query.filter(DagRun.run_id == dag_run_id).first()
- if not dag_run:
- raise NotFound("DAG Run not found")
-
- ti = dag_run.get_task_instance(task_id, session)
+ ti = (
+ session.query(TaskInstance)
+ .filter(TaskInstance.task_id == task_id, TaskInstance.run_id == dag_run_id)
+ .join(TaskInstance.dag_run)
+ .options(eagerload(TaskInstance.dag_run))
+ .one_or_none()
+ )
  if ti is None:
  metadata['end_of_log'] = True
- raise BadRequest(detail="Task instance did not exist in the DB")
+ raise NotFound(title="TaskInstance not found")
 
  dag = current_app.dag_bag.get_dag(dag_id)
  if dag:

diff --git a/airflow/api_connexion/endpoints/task_instance_endpoint.py b/airflow/api_connexion/endpoints/task_instance_endpoint.py
@@ -19,6 +19,7 @@
 from flask import current_app, request
 from marshmallow import ValidationError
 from sqlalchemy import and_, func
+from sqlalchemy.orm import eagerload
 
 from airflow.api_connexion import security
 from airflow.api_connexion.exceptions import BadRequest, NotFound
@@ -54,15 +55,14 @@ def get_task_instance(dag_id: str, dag_run_id: str, task_id: str, session=None):
  """Get task instance"""
  query = (
  session.query(TI)
- .filter(TI.dag_id == dag_id)
- .join(DR, and_(TI.dag_id == DR.dag_id, TI.execution_date == DR.execution_date))
- .filter(DR.run_id == dag_run_id)
- .filter(TI.task_id == task_id)
+ .filter(TI.dag_id == dag_id, DR.run_id == dag_run_id, TI.task_id == task_id)
+ .join(TI.dag_run)
+ .options(eagerload(TI.dag_run))
  .outerjoin(
  SlaMiss,
  and_(
  SlaMiss.dag_id == TI.dag_id,
- SlaMiss.execution_date == TI.execution_date,
+ SlaMiss.execution_date == DR.execution_date,
  SlaMiss.task_id == TI.task_id,
  ),
  )
@@ -127,13 +127,12 @@ def get_task_instances(
  session=None,
 ):
  """Get list of task instances."""
- base_query = session.query(TI)
+ base_query = session.query(TI).join(TI.dag_run).options(eagerload(TI.dag_run))
 
  if dag_id != "~":
  base_query = base_query.filter(TI.dag_id == dag_id)
  if dag_run_id != "~":
- base_query = base_query.join(DR, and_(TI.dag_id == DR.dag_id, TI.execution_date == DR.execution_date))
- base_query = base_query.filter(DR.run_id == dag_run_id)
+ base_query = base_query.filter(TI.run_id == dag_run_id)
  base_query = _apply_range_filter(
  base_query,
  key=DR.execution_date,
@@ -156,7 +155,7 @@ def get_task_instances(
  and_(
  SlaMiss.dag_id == TI.dag_id,
  SlaMiss.task_id == TI.task_id,
- SlaMiss.execution_date == TI.execution_date,
+ SlaMiss.execution_date == DR.execution_date,
  ),
  isouter=True,
  )
@@ -183,12 +182,12 @@ def get_task_instances_batch(session=None):
  data = task_instance_batch_form.load(body)
  except ValidationError as err:
  raise BadRequest(detail=str(err.messages))
- base_query = session.query(TI)
+ base_query = session.query(TI).join(TI.dag_run).options(eagerload(TI.dag_run))
 
  base_query = _apply_array_filter(base_query, key=TI.dag_id, values=data["dag_ids"])
  base_query = _apply_range_filter(
  base_query,
- key=TI.execution_date,
+ key=DR.execution_date,
  value_range=(data["execution_date_gte"], data["execution_date_lte"]),
  )
  base_query = _apply_range_filter(
@@ -214,7 +213,7 @@ def get_task_instances_batch(session=None):
  and_(
  SlaMiss.dag_id == TI.dag_id,
  SlaMiss.task_id == TI.task_id,
- SlaMiss.execution_date == TI.execution_date,
+ SlaMiss.execution_date == DR.execution_date,
  ),
  isouter=True,
  )
@@ -254,9 +253,7 @@ def post_clear_task_instances(dag_id: str, session=None):
  clear_task_instances(
  task_instances.all(), session, dag=dag, dag_run_state=State.RUNNING if reset_dag_runs else False
  )
- task_instances = task_instances.join(
- DR, and_(DR.dag_id == TI.dag_id, DR.execution_date == TI.execution_date)
- ).add_column(DR.run_id)
+ task_instances = task_instances.join(TI.dag_run).options(eagerload(TI.dag_run))
  return task_instance_reference_collection_schema.dump(
  TaskInstanceReferenceCollection(task_instances=task_instances.all())
  )
@@ -303,14 +300,6 @@ def post_set_task_instances_state(dag_id, session):
  future=data["include_future"],
  past=data["include_past"],
  commit=not data["dry_run"],
+ session=session,
  )
- execution_dates = {ti.execution_date for ti in tis}
- execution_date_to_run_id_map = dict(
- session.query(DR.execution_date, DR.run_id).filter(
- DR.dag_id == dag_id, DR.execution_date.in_(execution_dates)
- )
- )
- tis_with_run_id = [(ti, execution_date_to_run_id_map.get(ti.execution_date)) for ti in tis]
- return task_instance_reference_collection_schema.dump(
- TaskInstanceReferenceCollection(task_instances=tis_with_run_id)
- )
+ return task_instance_reference_collection_schema.dump(TaskInstanceReferenceCollection(task_instances=tis))
diff --git a/airflow/api_connexion/schemas/task_instance_schema.py b/airflow/api_connexion/schemas/task_instance_schema.py
@@ -134,18 +134,10 @@ class TaskInstanceReferenceSchema(Schema):
  """Schema for the task instance reference schema"""
 
  task_id = fields.Str()
- dag_run_id = fields.Str()
+ run_id = fields.Str(data_key="dag_run_id")
  dag_id = fields.Str()
  execution_date = fields.DateTime()
 
- def get_attribute(self, obj, attr, default):
- """Overwritten marshmallow function"""
- task_instance_attr = ['task_id', 'execution_date', 'dag_id']
- if attr in task_instance_attr:
- obj = obj[0] # As object is a tuple of task_instance and dag_run_id
- return get_value(obj, attr, default)
- return obj[1]
-
 
 class TaskInstanceReferenceCollection(NamedTuple):
  """List of objects with metadata about taskinstance and dag_run_id"""

diff --git a/airflow/cli/commands/dag_command.py b/airflow/cli/commands/dag_command.py
@@ -89,9 +89,11 @@ def dag_backfill(args, dag=None):
 
  if args.dry_run:
  print(f"Dry run of DAG {args.dag_id} on {args.start_date}")
+ dr = DagRun(dag.dag_id, execution_date=args.start_date)
  for task in dag.tasks:
  print(f"Task {task.task_id}")
- ti = TaskInstance(task, args.start_date)
+ ti = TaskInstance(task, run_id=None)
+ ti.dag_run = dr
  ti.dry_run()
  else:
  if args.reset_dagruns:

diff --git a/airflow/cli/commands/kubernetes_command.py b/airflow/cli/commands/kubernetes_command.py
@@ -26,7 +26,7 @@
 from airflow.kubernetes import pod_generator
 from airflow.kubernetes.kube_client import get_kube_client
 from airflow.kubernetes.pod_generator import PodGenerator
-from airflow.models import TaskInstance
+from airflow.models import DagRun, TaskInstance
 from airflow.settings import pod_mutation_hook
 from airflow.utils import cli as cli_utils, yaml
 from airflow.utils.cli import get_dag
@@ -38,9 +38,11 @@ def generate_pod_yaml(args):
  execution_date = args.execution_date
  dag = get_dag(subdir=args.subdir, dag_id=args.dag_id)
  yaml_output_path = args.output_path
+ dr = DagRun(dag.dag_id, execution_date=execution_date)
  kube_config = KubeConfig()
  for task in dag.tasks:
- ti = TaskInstance(task, execution_date)
+ ti = TaskInstance(task, None)
+ ti.dag_run = dr
  pod = PodGenerator.construct_pod(
  dag_id=args.dag_id,
  task_id=ti.task_id,