Rich-T-kid opened a new pull request, #25128:
URL: https://github.com/apache/datafusion/pull/25128
## Which issue does this PR close?
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- Closes #25127.
## Rationale for this change
RepartitionExec is one of the most frequently executed operators in
DataFusion, every parallel query goes through it, but there were no dedicated
benchmarks for it.
also see #25127
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## What changes are included in this PR?
Adds `datafusion/physical-plan/benches/repartition.rs` with two categories
of benchmarks:
BatchPartitioner microbenchmarks (no async, pure CPU routing cost):
- `hash_partitioner/partition_count` — sweeps power-of-two and
non-power-of-two counts (8, 10, 16, 32, 64, 100, 128), exercising both branches
of StrengthReducedU64 (bitmask vs. reciprocal multiply)
- `hash_partitioner/key_type` — compares Int32, Int64, and Utf8View hashing
cost at 32 partitions
- `hash_partitioner/key_count` — 1, 2, and 3 composite key columns at 32
partitions, showing per-key overhead
- `round_robin_partitioner/partition_count` — trivial routing baseline for
isolating channel overhead from hash cost
End-to-end RepartitionExec benchmarks (full async path, 5M rows):
- `repartition_exec/hash_1_to_n` — 1 input → N outputs (4, 8, 16, 32) with
hash partitioning
- `repartition_exec/round_robin_1_to_n` — same topology with round-robin,
for direct comparison against hash
- `repartition_exec/hash_n_to_n` — N inputs → N outputs (4, 8, 16), the
typical concurrent-producer scenario
- `repartition_exec/hash_m_to_n` — asymmetric topologies: consolidation
(16→4, 16→8, 32→8) and fan-out (4→16, 8→16, 8→32)
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## What is the testing strategy for this PR?
n/a
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## Are there any user-facing changes?
no
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