Don't pass extension arrays through the compressor unchanged

[robert3005]

The compressor indicates whether the array was returned unchanged. Extension scheme canonicalises input and only keeps extension scheme compressed arrays if they actually compressed anything instead of returning input unchanged

fix #10417

[codspeed]

Merging this PR will regress 1 benchmark

⚠️ Unknown Walltime execution environment detected

Using the Walltime instrument on standard Hosted Runners will lead to inconsistent data.

For the most accurate results, we recommend using CodSpeed Macro Runners: bare-metal machines fine-tuned for performance measurement consistency.

⚠️ 1 benchmark measured no execution time

Nothing ran under measurement, usually because the compiler removed the code under test. This result is not comparable, so it counts as unchanged.

Preventing compiler optimizations

• bench_compare_primitive[(10000, 2)]

⚠️ 14 benchmarks spent significant time in system calls

System calls cannot be consistently instrumented, so they are not included in the measure, which understates the real cost. Please switch to the Walltime instrument to accurately measure system calls.

Measurement and system calls

• density_sweep_dense_runs[0.001]
• filter_powerlaw_by_mostly_true[250000]
• pcodec_compress_f64
• density_sweep_dense_runs[0.9]
• random_i128[0.01]
• take_varbin
• multipolygon_mixed_validity
• zstd_compress_string
• decompress[u32, (1000, 256)]
• filter_run_end[len=4096_run=16_density=0.1]
• …and 4 more

⚡ 2 improved benchmarks
❌ 1 regressed benchmark
✅ 2180 untouched benchmarks
⏩ 359 skipped benchmarks¹

Warning

Please fix the performance issues or acknowledge them on CodSpeed.

Performance Changes

	Mode	Benchmark	BASE	HEAD	Efficiency
❌	WallTime	bitpack_blocked_compress_avx2	6.7 µs	7.6 µs	-11.45%
⚡ ⚠️	Simulation	density_sweep_dense_runs[0.001]	47.8 µs	29.7 µs	+60.79%
⚡ ⚠️	Simulation	filter_powerlaw_by_mostly_true[250000]	150.2 µs	103.7 µs	+44.77%

Tip

Investigate this regression by commenting @codspeedbot fix this regression on this PR, or directly use the CodSpeed MCP with your agent.

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_{Comparing rk/compress-explicit-fallback (c3ad942) with develop (731a231)}

Footnotes

1. 359 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩