defmodule Microwaveprop.Repo.Migrations.DropPropagationScores do
  use Ecto.Migration

  @moduledoc """
  Propagation scores live on disk at `/data/scores` as binary files
  now, not in Postgres. Dropping the table (and its indexes + the
  earlier tuning migrations that touch it) removes the biggest write
  contention source from the propagation chain.

  Not reversible in `change/0` — there's nothing meaningful to
  restore if this gets rolled back, since the data is rebuilt from
  HRRR every 3 hours.
  """

  def up do
    drop_if_exists table(:propagation_scores)
  end

  def down do
    raise Ecto.MigrationError, "drop_propagation_scores is not reversible"
  end
end
