This was discussed in open source slack and I have documented the discussion on github here https://github.com/apache/airflow/discussions/43235.
Formally, the proposal here is, in new airflow 3.0 backfill (AIP-78), we will not provide a mechanism to override the pool set on the dag. At least, for now we won't -- not that we can't change minds in future. Some background. Pre-airflow 3.0, backfill actually *completely ignored *pools. And it *only* scheduled tasks in a specific pool if you provided an override when running backfill command. And in that case, all tasks in the dag would be given that pool. If no one objects, this vote will pass 3 days from now, 1pm pacific Thursday Oct 24, 2024. Ordinarily I would have created a discuss thread first, but since there seemed to be unanimity on the side of removing pool override as an option, I went straight to vote.
