feat: improve the random access file benchmark

[westonpace]

I've been using this benchmark for a number of potential reader improvements and made it more representative of real world use cases by adding multiple threads, more depth per thread, and a no-cache mode to force the data to be read from disk.

[github-actions]

Code Review

P0: Potential Bug - Compilation Failure on Non-Linux Platforms

The drop_file_from_cache function is only defined for #[cfg(target_os = "linux")], but it's called unconditionally in the benchmark loop (line ~376 in diff). This will cause a compilation error on macOS and Windows.

Suggested fix: Either:

1. Add a no-op stub for non-linux platforms
2. Or conditionally skip the no-cache benchmarks on non-linux with a cfg attribute

P1: Data Size vs Index Calculation Mismatch

The benchmark generates 500M rows (500 * 1024 * 1024), but creates indices for only 100K rows with a gap of 5K between them. The maximum index would be 99,999 * 5,120 = 511,994,880, which is close to the data size of 524,288,000. This is fine, but the 500MB+ file generation per benchmark configuration seems excessive for CI environments. Consider documenting this or adding a way to run with smaller data for quick local testing.

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Overall, the benchmark improvements look well-structured and useful for real-world performance testing. Just the platform compatibility issue needs to be addressed before merge.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

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