Benchmark: Dux flat SQL for single-op pipelines (PR #50)

bench_flat_sql.exs

# Benchmark: flat SQL for single-op pipelines
#
# Usage: mix run bench_flat_sql.exs

require Dux

num_rows = 1_000_000
IO.puts("Generating #{num_rows} rows...")

data =
  Enum.map(1..num_rows, fn _ ->
    %{
      region: Enum.random(~w(North South East West Central)),
      product: Enum.random(~w(Widget Gadget Doohickey Thingamajig Gizmo)),
      quantity: :rand.uniform(100),
      price: Float.round(:rand.uniform() * 500, 2),
      date: Date.from_iso8601!("2025-01-15")
    }
  end)

dux = Dux.from_list(data) |> Dux.compute()

IO.puts("Running benchmarks...\n")

Benchee.run(
  %{
    "compute: filter" => fn ->
      dux |> Dux.filter(quantity > 50 and price > 100.0) |> Dux.compute()
    end,
    "compute: mutate" => fn ->
      dux |> Dux.mutate(revenue: quantity * price) |> Dux.compute()
    end,
    "compute: group_by+summarise" => fn ->
      dux
      |> Dux.group_by(:region)
      |> Dux.summarise(total: sum(quantity), avg_price: avg(price))
      |> Dux.compute()
    end,
    "e2e: filter → to_rows" => fn ->
      dux |> Dux.filter(quantity > 50 and price > 100.0) |> Dux.to_rows()
    end,
    "e2e: summarise → to_rows" => fn ->
      dux
      |> Dux.group_by(:region)
      |> Dux.summarise(total: sum(quantity), avg_price: avg(price))
      |> Dux.to_rows()
    end
  },
  warmup: 2,
  time: 5,
  memory_time: 0
)

_ = dux