bench: cover dictionary group keys with a shared values array - #25198
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LiaCastaneda wants to merge 1 commit into
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bench: cover dictionary group keys with a shared values array#25198LiaCastaneda wants to merge 1 commit into
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Codecov Report✅ All modified and coverable lines are covered by tests. Additional details and impacted files@@ Coverage Diff @@
## main #25198 +/- ##
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- Coverage 81.91% 81.91% -0.01%
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Files 1132 1132
Lines 421314 421314
Branches 421314 421314
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- Hits 345135 345126 -9
- Misses 55771 55779 +8
- Partials 20408 20409 +1 ☔ View full report in Codecov by Harness. 🚀 New features to boost your workflow:
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Some results in my local machine with main against #25185 using these benchmarks summary: |
Rich-T-kid
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Sep 11, 2026
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LGTM, left some non blocking comments
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| let mut group = c.benchmark_group("dict_shared_values_arc"); | ||
| let size = SIZES[0]; | ||
| let mut rng = StdRng::seed_from_u64(SEED); |
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I think we can re-use the seed at the top of the file
| let size = SIZES[0]; | ||
| let mut rng = StdRng::seed_from_u64(SEED); | ||
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| for &cardinality in &[size, 100_000, 500_000] { |
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nit : I think the jump from 8k -> 100k is a bit steep. could we introduce 32k or 64k as an intermediate cardinality size?
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Which issue does this PR close?
Related to #24822. No issue closed.
Rationale for this change
The benchmarks in this file build a fresh values array per batch and cap cardinality at the batch size. Neither shape matches a real plan:
takeandfilterclone the valuesArcand rewrite only the keys, so batches downstream of a repartition share one values array, and because it is never compacted its cardinality can far exceed the rows in a batch. Per-batch work that scales with dictionary cardinality is invisible under the current parameters.What changes are included in this PR?
Adds
bench_shared_values_arc: 32 batches of 8192 rows sharing one values array, at cardinalities 8192, 100k and 500k.What is the testing strategy for this PR?
Benchmark-only. Ran the bench locally and
cargo clippy --all-targets -D warnings.Are there any user-facing changes?
No