bench: add nested-type (List/Struct/Map) cases to first_value/last_value benchmark

[zhuqi-lucas]

Which issue does this PR close?

Groundwork for benchmarking #23628 (native GroupsAccumulator for nested value types in first_value / last_value).

Rationale for this change

The first_last benchmark only covers primitive value types today. #23628 adds a native GroupsAccumulator for nested value types (List, Struct, Map), which previously fell back to one per-group Accumulator via GroupsAccumulatorAdapter. To measure that work we need nested-type cases in the benchmark.

Landing this first (with the fallback path on current main) means that once #23628 is in flight, a run benchmark first_last diff shows the fallback → native speedup per type automatically.

What changes are included in this PR?

• Adds List<Int64>, Struct<i64,utf8,f64>, Map<utf8,i64> and a composite List<Struct<i64,utf8>> value column, each with the same coverage as the primitive cases: first_value/last_value update + merge, plus first_value evaluate, at 0% and 90% nulls.
• prepare_typed_groups_accumulator now mirrors the planner: it uses the native GroupsAccumulator when the value type is supported and otherwise falls back to a GroupsAccumulatorAdapter around one per-group Accumulator. The same benchmark case therefore runs the fallback on a build without native nested support and the native path on one that has it.

Are these changes tested?

Benchmark-only. Runs locally on main (all nested cases exercise the fallback path). As a preview of the intended signal, first_value struct update goes ~112ms (fallback) → ~24ms (native, with #23628) at 1024 groups.

Are there any user-facing changes?

No — benchmark only.

[Copilot]

Pull request overview

This PR extends the first_last Criterion benchmark in datafusion-functions-aggregate to cover nested value types (List/Struct/Map and a composite List), and updates the benchmark harness to exercise either the native GroupsAccumulator implementation or the adapter-based fallback path, depending on type support.

Changes:

• Add nested-type benchmark cases for first_value/last_value update + merge, plus first_value evaluate, at two null-density settings.
• Generalize the benchmark accumulator construction to be value-type aware and introduce an explicit adapter fallback factory.
• Add nested array generators (StructArray, ListArray, MapArray, List<Struct>) for benchmark inputs.

Suppressed comments (2)

datafusion/functions-aggregate/benches/first_last.rs:450

• This label uses nulls={pct}%, but in the nested generators pct controls inner/payload null density (fields/elements/values) rather than top-level nulls. Renaming avoids misleading benchmark output.

                    &format!("{fn_label} merge_bench {type_label} nulls={pct}%"),

datafusion/functions-aggregate/benches/first_last.rs:461

• This label uses nulls={pct}%, but in the nested generators pct controls inner/payload null density (fields/elements/values) rather than top-level nulls. Renaming avoids misleading benchmark output.

                &format!("first_value evaluate_bench {type_label} nulls={pct}%, all"),

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[kosiew]

@zhuqi-lucas
Thanks for the quick benchmark!
I took a look at the changes and didn't find any blocking issues or suggestions. The touched code is benchmark-only, and the explicit native vs planner fallback construction makes sense here because it provides a clear comparison between #23628 and the current main branch.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 80.89%. Comparing base (a3f0f93) to head (ec11fef).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #24075      +/-   ##
==========================================
- Coverage   80.89%   80.89%   -0.01%     
==========================================
  Files        1102     1102              
  Lines      376085   376093       +8     
  Branches   376085   376093       +8     
==========================================
- Hits       304230   304229       -1     
- Misses      53747    53755       +8     
- Partials    18108    18109       +1     

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[zhuqi-lucas]

Thank you @kosiew for review, merged now.