"pool_slots" may be None

[suiting-young]

airflow/airflow/jobs/scheduler_job.py

Line 1041 in b1ce429

if task_instance.pool_slots > open_slots:

This would trigger error

TypeError: '>' not supported between instances of 'NoneType' and 'int'

as the task_instance is fetched directly (without the patch of refresh_from_db)

airflow/airflow/jobs/scheduler_job.py

Lines 930 to 935 in b1ce429

	task_instances_to_examine: List[TI] = with_row_locks(
	query,
	of=TI,
	session=session,
	**skip_locked(session=session),
	).all()

Related to #8153.

[boring-cyborg]

Thanks for opening your first issue here! Be sure to follow the issue template!

[XD-DENG]

Hi @suiting-young , may you please share the specific steps reproducing the error?

[suiting-young]

@XD-DENG after upgrade my instance from 1.10.14 to 2.0.1, some very old TI-s were fetched by scheduler.
I think those TI were interrupted (not in finished state) for some reason long ago, and ideally already expired.
Maybe the new scheduler changed some rules, as those data didn't trigger problem on 1.10.14 (which already has pool_slots property).

[kaxil]

This was fixed in #14406 and will be available as part of 2.0.2

[kaxil]

Workaround is to run:

UPDATE task_instance SET pool_slots = 1 WHERE pool_slots IS NULL;