perf: reuse hash values across partial aggregation, repartition, and final - #2
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naman-modi wants to merge 1 commit into
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perf: reuse hash values across partial aggregation, repartition, and final#2naman-modi wants to merge 1 commit into
naman-modi wants to merge 1 commit into
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…final aggregation Apply upstream PR apache#23720: the group-key hash computed by the partial aggregation is carried through the hash repartition and reused by the final aggregation instead of being recomputed at each stage.
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Engine-level benchmark showed no gain (flat to slightly negative on the aggregate-heavy suite), so this is not kept. The hash-reuse idea stays available on branch agg-hashreuse if the picture changes. |
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What does this PR do?
Carries the group-key hash from the partial aggregation through the hash repartition into the final aggregation, so it is computed once per row instead of at each stage (upstream PR apache#23720 applied onto this line).
Testing
Local: datafusion-physical-plan (1571) + datafusion-physical-expr-common (75) unit tests green; the PR's own execution test suite (45 tests incl. hash_reuse) green.
Merge gate: held open until the engine-level benchmark confirms the gain; merged only if kept.