**Apache Airflow version: 2.0.1**
**What happened:**
Running an airflow dags test or backfill  CLI command shown in tutorial, produces the same error.

**dags test cli command result：**

```
(airflow_venv) (base) app@lunar_01:airflow$ airflow dags test tutorial 2015-06-01
[2021-02-16 04:29:22,355] {dagbag.py:448} INFO - Filling up the DagBag from /home/app/Lunar/src/airflow/dags
[2021-02-16 04:29:22,372] {example_kubernetes_executor_config.py:174} WARNING - Could not import DAGs in example_kubernetes_executor_config.py: No module named 'kubernetes'
[2021-02-16 04:29:22,373] {example_kubernetes_executor_config.py:175} WARNING - Install kubernetes dependencies with: pip install apache-airflow['cncf.kubernetes']
Traceback (most recent call last):
  File "/home/app/airflow_venv/bin/airflow", line 10, in <module>
    sys.exit(main())
  File "/home/app/airflow_venv/lib/python3.7/site-packages/airflow/__main__.py", line 40, in main
    args.func(args)
  File "/home/app/airflow_venv/lib/python3.7/site-packages/airflow/cli/cli_parser.py", line 48, in command
    return func(*args, **kwargs)
  File "/home/app/airflow_venv/lib/python3.7/site-packages/airflow/utils/session.py", line 65, in wrapper
    return func(*args, session=session, **kwargs)
  File "/home/app/airflow_venv/lib/python3.7/site-packages/airflow/utils/cli.py", line 89, in wrapper
    return f(*args, **kwargs)
  File "/home/app/airflow_venv/lib/python3.7/site-packages/airflow/cli/commands/dag_command.py", line 389, in dag_test
    dag.run(executor=DebugExecutor(), start_date=args.execution_date, end_date=args.execution_date)
  File "/home/app/airflow_venv/lib/python3.7/site-packages/airflow/models/dag.py", line 1706, in run
    job.run()
  File "/home/app/airflow_venv/lib/python3.7/site-packages/airflow/jobs/base_job.py", line 237, in run
    self._execute()
  File "/home/app/airflow_venv/lib/python3.7/site-packages/airflow/utils/session.py", line 65, in wrapper
    return func(*args, session=session, **kwargs)
  File "/home/app/airflow_venv/lib/python3.7/site-packages/airflow/jobs/backfill_job.py", line 805, in _execute
    session=session,
  File "/home/app/airflow_venv/lib/python3.7/site-packages/airflow/utils/session.py", line 62, in wrapper
    return func(*args, **kwargs)
  File "/home/app/airflow_venv/lib/python3.7/site-packages/airflow/jobs/backfill_job.py", line 715, in _execute_for_run_dates
    tis_map = self._task_instances_for_dag_run(dag_run, session=session)
  File "/home/app/airflow_venv/lib/python3.7/site-packages/airflow/utils/session.py", line 62, in wrapper
    return func(*args, **kwargs)
  File "/home/app/airflow_venv/lib/python3.7/site-packages/airflow/jobs/backfill_job.py", line 359, in _task_instances_for_dag_run
    dag_run.refresh_from_db()
  File "/home/app/airflow_venv/lib/python3.7/site-packages/airflow/utils/session.py", line 65, in wrapper
    return func(*args, session=session, **kwargs)
  File "/home/app/airflow_venv/lib/python3.7/site-packages/airflow/models/dagrun.py", line 178, in refresh_from_db
    DR.run_id == self.run_id,
  File "/home/app/airflow_venv/lib/python3.7/site-packages/sqlalchemy/orm/query.py", line 3500, in one
    raise orm_exc.NoResultFound("No row was found for one()")
sqlalchemy.orm.exc.NoResultFound: No row was found for one()
```

**backfill cli command result:**
```
(airflow_venv) (base) app@lunar_01:airflow$ airflow dags backfill tutorial --start-date 2015-06-01 --end-date 2015-06-07
/home/app/airflow_venv/lib/python3.7/site-packages/airflow/cli/commands/dag_command.py:62 PendingDeprecationWarning: --ignore-first-depends-on-past is deprecated as the value is always set to True
[2021-02-16 04:30:16,979] {dagbag.py:448} INFO - Filling up the DagBag from /home/app/Lunar/src/airflow/dags
[2021-02-16 04:30:16,996] {example_kubernetes_executor_config.py:174} WARNING - Could not import DAGs in example_kubernetes_executor_config.py: No module named 'kubernetes'
[2021-02-16 04:30:16,996] {example_kubernetes_executor_config.py:175} WARNING - Install kubernetes dependencies with: pip install apache-airflow['cncf.kubernetes']
Traceback (most recent call last):
  File "/home/app/airflow_venv/bin/airflow", line 10, in <module>
    sys.exit(main())
  File "/home/app/airflow_venv/lib/python3.7/site-packages/airflow/__main__.py", line 40, in main
    args.func(args)
  File "/home/app/airflow_venv/lib/python3.7/site-packages/airflow/cli/cli_parser.py", line 48, in command
    return func(*args, **kwargs)
  File "/home/app/airflow_venv/lib/python3.7/site-packages/airflow/utils/cli.py", line 89, in wrapper
    return f(*args, **kwargs)
  File "/home/app/airflow_venv/lib/python3.7/site-packages/airflow/cli/commands/dag_command.py", line 116, in dag_backfill
    run_backwards=args.run_backwards,
  File "/home/app/airflow_venv/lib/python3.7/site-packages/airflow/models/dag.py", line 1706, in run
    job.run()
  File "/home/app/airflow_venv/lib/python3.7/site-packages/airflow/jobs/base_job.py", line 237, in run
    self._execute()
  File "/home/app/airflow_venv/lib/python3.7/site-packages/airflow/utils/session.py", line 65, in wrapper
    return func(*args, session=session, **kwargs)
  File "/home/app/airflow_venv/lib/python3.7/site-packages/airflow/jobs/backfill_job.py", line 805, in _execute
    session=session,
  File "/home/app/airflow_venv/lib/python3.7/site-packages/airflow/utils/session.py", line 62, in wrapper
    return func(*args, **kwargs)
  File "/home/app/airflow_venv/lib/python3.7/site-packages/airflow/jobs/backfill_job.py", line 715, in _execute_for_run_dates
    tis_map = self._task_instances_for_dag_run(dag_run, session=session)
  File "/home/app/airflow_venv/lib/python3.7/site-packages/airflow/utils/session.py", line 62, in wrapper
    return func(*args, **kwargs)
  File "/home/app/airflow_venv/lib/python3.7/site-packages/airflow/jobs/backfill_job.py", line 359, in _task_instances_for_dag_run
    dag_run.refresh_from_db()
  File "/home/app/airflow_venv/lib/python3.7/site-packages/airflow/utils/session.py", line 65, in wrapper
    return func(*args, session=session, **kwargs)
  File "/home/app/airflow_venv/lib/python3.7/site-packages/airflow/models/dagrun.py", line 178, in refresh_from_db
    DR.run_id == self.run_id,
  File "/home/app/airflow_venv/lib/python3.7/site-packages/sqlalchemy/orm/query.py", line 3500, in one
    raise orm_exc.NoResultFound("No row was found for one()")
sqlalchemy.orm.exc.NoResultFound: No row was found for one()
```
airflow/models/dagrun.py
from airflow.models.taskinstance import TaskInstance as TI
from airflow.stats import Stats
from airflow.ti_deps.dep_context import DepContext
from airflow.ti_deps.dependencies_states import SCHEDULEABLE_STATES
from airflow.utils import callback_requests, timezone
from airflow.utils.log.logging_mixin import LoggingMixin
from airflow.utils.session import provide_session
from airflow.utils.sqlalchemy import UtcDateTime, nulls_first, skip_locked, with_row_locks
from airflow.utils.state import State, TaskInstanceState
from airflow.utils.types import DagRunType
if TYPE_CHECKING:
    from airflow.models.dag import DAG
class TISchedulingDecision(NamedTuple):
    """Type of return for DagRun.task_instance_scheduling_decisions"""
    tis: List[TI]
    schedulable_tis: List[TI]
    changed_tis: bool
    unfinished_tasks: List[TI]
    finished_tasks: List[TI]
class DagRun(Base, LoggingMixin):
    """
    DagRun describes an instance of a Dag. It can be created
    by the scheduler (for regular runs) or by an external trigger
    """
    __tablename__ = "dag_run"
    __NO_VALUE = object()
    id = Column(Integer, primary_key=True)
    dag_id = Column(String(ID_LEN))
    queued_at = Column(UtcDateTime)
    execution_date = Column(UtcDateTime, default=timezone.utcnow)