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Posted to github@datafusion.apache.org by "wirybeaver (via GitHub)" <gi...@apache.org> on 2026/05/18 22:55:19 UTC
[PR] feat(aqe): add JobLimitTracker for early-stop on global LIMIT [datafusion-ballista]
wirybeaver opened a new pull request, #1727:
URL: https://github.com/apache/datafusion-ballista/pull/1727
Pure-logic atomic counter that aggregates per-stage row counts and fires a one-shot CancelRemaining decision when the running sum crosses limit * safety_factor. Foundation for the AQE early-stop feature (#1359): subsequent commits add the plan-time eligibility analyzer, scheduler-side wiring into update_task_statuses, and an EarlyStopCancel event that finalizes the job as Successful with partial output.
Trigger uses AtomicU64 fetch_add (Relaxed) for row accumulation and AtomicBool swap (SeqCst) on the triggered flag so that, across racing observers, exactly one CancelRemaining is returned. Threshold is computed in fixed-point arithmetic to avoid f64 imprecision at large limits.
The observe() path carries an asymmetric correctness invariant: we must fire no earlier than sum >= limit (firing early would cause the downstream LimitExec to under-report). Firing late is always safe; it only wastes I/O.
Includes 9 unit tests covering threshold rounding, below/at/above trigger transitions, single-fire guarantee, untagged-stage handling, multi-stage aggregation, 32-thread concurrent observer race, and constructor preconditions.
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Re: [PR] [WIP] feat(aqe): early-stop on global LIMIT [datafusion-ballista]
Posted by "milenkovicm (via GitHub)" <gi...@apache.org>.
milenkovicm commented on PR #1727:
URL: https://github.com/apache/datafusion-ballista/pull/1727#issuecomment-5645551485
closing as open for too long without progress, please reopen if still needed and updated
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Re: [PR] [WIP] feat(aqe): early-stop on global LIMIT [datafusion-ballista]
Posted by "milenkovicm (via GitHub)" <gi...@apache.org>.
milenkovicm closed pull request #1727: [WIP] feat(aqe): early-stop on global LIMIT
URL: https://github.com/apache/datafusion-ballista/pull/1727
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