zhuqi-lucas commented on issue #16353: URL: https://github.com/apache/datafusion/issues/16353#issuecomment-2970055623
> > So it means this sub-task corner case can be resolved? > > Yes, that's correct. > > > I am curious what's the budget count since we can't config it from datafusion, will it affect performance or other things? It seems not, because we already use RecordBatchReceiverStream for the budget? > > [@zhuqi-lucas](https://github.com/zhuqi-lucas) that's correct, you can't configure it at the moment. That's the case for `RecordBatchReceiverStream` today as well indeed. Tokio hardcodes the magic number `128` (see https://github.com/tokio-rs/tokio/blob/master/tokio/src/task/coop/mod.rs#L116). > > > If we have to share the one budget for all leaf nodes, will some leaf node very aggressive consuming budget will affect the total fairness or performance? > > The budget is per spawned task. Every time the tokio scheduler lets a task run it gives it a budget of 128 which the task can then deplete until it hits zero. Then the task is coaxed towards yielding by making all budget aware Tokio resources return `Pending`. From the perspective of DataFusion code I don't think this really changes all that much. It's the exact same behavior you have today already when the source streams are `RecordBatchReceiverStream`. So the moment you have a repartition/coalesce you're getting exactly this with the current code. Got it, it makes sense to me @pepijnve! Thanks! -- 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: github-unsubscr...@datafusion.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: github-unsubscr...@datafusion.apache.org For additional commands, e-mail: github-h...@datafusion.apache.org
