Function make_data

datafusion/core/benches/data_utils/mod.rs:198–272

(
    partition_cnt: i32,
    sample_cnt: i32,
    asc: bool,
    use_view: bool,
)

#[expect(clippy::allow_attributes)] // some issue where expect(dead_code) doesn't fire properly
#[allow(dead_code)]
pub(crate) fn make_data(
    partition_cnt: i32,
    sample_cnt: i32,
    asc: bool,
    use_view: bool,
) -> Result<(Arc<Schema>, Vec<Vec<RecordBatch>>), DataFusionError> {
    // constants observed from trace data
    let simultaneous_group_cnt = 2000;
    let fitted_shape = 12f64;
    let fitted_scale = 5f64;
    let mean = 0.1;
    let stddev = 1.1;
    let pareto = Pareto::new(fitted_scale, fitted_shape).unwrap();
    let normal = Normal::new(mean, stddev).unwrap();
    let mut rng = rand::rngs::SmallRng::from_seed([0; 32]);

    // populate data
    let schema = test_schema(use_view);
    let mut partitions = vec![];
    let mut cur_time = 16909000000000i64;
    for _ in 0..partition_cnt {
        // Choose the appropriate builder based on use_view.
        let mut id_builder = if use_view {
            TraceIdBuilder::Utf8View(StringViewBuilder::new())
        } else {
            TraceIdBuilder::Utf8(StringBuilder::new())
        };

        let mut ts_builder = Int64Builder::new();
        let gen_id = |rng: &mut rand::rngs::SmallRng| {
            rng.random::<[u8; 16]>()
                .iter()
                .fold(String::new(), |mut output, b| {
                    let _ = write!(output, "{b:02X}");
                    output
                })
        };
        let gen_sample_cnt =
            |mut rng: &mut rand::rngs::SmallRng| pareto.sample(&mut rng).ceil() as u32;
        let mut group_ids = (0..simultaneous_group_cnt)
            .map(|_| gen_id(&mut rng))
            .collect::<Vec<_>>();
        let mut group_sample_cnts = (0..simultaneous_group_cnt)
            .map(|_| gen_sample_cnt(&mut rng))
            .collect::<Vec<_>>();
        for _ in 0..sample_cnt {
            let random_index = rng.random_range(0..simultaneous_group_cnt);
            let trace_id = &mut group_ids[random_index];
            let sample_cnt = &mut group_sample_cnts[random_index];
            *sample_cnt -= 1;
            if *sample_cnt == 0 {
                *trace_id = gen_id(&mut rng);
                *sample_cnt = gen_sample_cnt(&mut rng);
            }

            id_builder.append_value(trace_id);
            ts_builder.append_value(cur_time);