Batch upstream map-length lookups when resolving mapped kwargs - #70620
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rjgoyln wants to merge 5 commits into
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Batch upstream map-length lookups when resolving mapped kwargs#70620rjgoyln wants to merge 5 commits into
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This only covers the batching part, not memoizing, so “closing” is wrong. |
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OK. I got it. Thanks. |
uranusjr
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uranusjr
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uranusjr
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uranusjr
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uranusjr
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The local imports were carried over from the neighbouring lookup rather than required by anything: no import cycle forces them, and airflow.models is already a top-level dependency of this module. Feeding update() straight from the result rows avoids allocating a mapping that is discarded immediately.
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uranusjr
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Is it possible to further reduce the query with |
uranusjr
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Thanks for the suggestion. I benchmarked the Advantages
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I have the prototype ready. Let me know if you think the 0.8ms speedup is worth the added complexity, and I can push it! |
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Summary
Resolving mapped task kwargs previously issued one database query per
XComArg, causing N+1 queries for expanded kwargs (especially with nestedzip()/concat()). This change replaces those repeated lookups with a bulk prefetch, addressing the long-standing TODO inSchedulerDictOfListsExpandInput._get_map_lengths.Upstream map lengths are now resolved in a fixed number of queries, improving both scheduler expansion and execution API argument binding.
Changes
prefetch_map_lengths()to resolve all referenced upstream map lengths in bulk.lengthsparameter toget_task_map_length()and use prefetched results when available.SchedulerDictOfListsExpandInputandSchedulerListOfDictsExpandInput.Testing
mypy-airflow-coreand pre-commit checks pass.-->
Was generative AI tooling used to co-author this PR?
Drafted-by: Claude Code (Opus 5)
{pr_number}.significant.rst, in airflow-core/newsfragments. You can add this file in a follow-up commit after the PR is created so you know the PR number.