class MigrateBuildStageReference < ActiveRecord::Migration
  include Gitlab::Database::MigrationHelpers

  DOWNTIME = false

  def up
    disable_statement_timeout

    stage_id = Arel.sql <<-SQL.strip_heredoc
      (SELECT id FROM ci_stages
         WHERE ci_stages.pipeline_id = ci_builds.commit_id
           AND ci_stages.name = ci_builds.stage)
    SQL

    update_column_in_batches(:ci_builds, :stage_id, stage_id) do |table, query|
      query.where(table[:stage_id].eq(nil))
    end
  end

  def down
    disable_statement_timeout

    update_column_in_batches(:ci_builds, :stage_id, nil)
  end
end
