1 files changed, 49 insertions, 0 deletions
diff --git a/db/post_migrate/20210825193652_backfill_cadence_id_for_boards_scoped_to_iteration.rb b/db/post_migrate/20210825193652_backfill_cadence_id_for_boards_scoped_to_iteration.rb
new file mode 100644
index 00000000000..f350fbe3d12
--- /dev/null
+++ b/db/post_migrate/20210825193652_backfill_cadence_id_for_boards_scoped_to_iteration.rb
@@ -0,0 +1,49 @@
+# frozen_string_literal: true
+
+class BackfillCadenceIdForBoardsScopedToIteration < Gitlab::Database::Migration[1.0]
+  disable_ddl_transaction!
+
+  BATCH_SIZE = 1000
+  DELAY = 2.minutes.to_i
+  MIGRATION = 'BackfillIterationCadenceIdForBoards'
+
+  class MigrationBoard < ApplicationRecord
+    include EachBatch
+
+    self.table_name = 'boards'
+  end
+
+  def up
+    schedule_backfill_group_boards
+    schedule_backfill_project_boards
+  end
+
+  def down
+    MigrationBoard.where.not(iteration_cadence_id: nil).each_batch(of: BATCH_SIZE) do |batch, index|
+      range = batch.pluck(Arel.sql('MIN(id)'), Arel.sql('MAX(id)')).first
+      delay = index * DELAY
+
+      migrate_in(delay, MIGRATION, ['none', 'down', *range])
+    end
+  end
+
+  private
+
+  def schedule_backfill_project_boards
+    MigrationBoard.where(iteration_id: -4).where.not(project_id: nil).where(iteration_cadence_id: nil).each_batch(of: BATCH_SIZE) do |batch, index|
+      range = batch.pluck(Arel.sql('MIN(id)'), Arel.sql('MAX(id)')).first
+      delay = index * DELAY
+
+      migrate_in(delay, MIGRATION, ['project', 'up', *range])
+    end
+  end
+
+  def schedule_backfill_group_boards
+    MigrationBoard.where(iteration_id: -4).where.not(group_id: nil).where(iteration_cadence_id: nil).each_batch(of: BATCH_SIZE) do |batch, index|
+      range = batch.pluck(Arel.sql('MIN(id)'), Arel.sql('MAX(id)')).first
+      delay = index * DELAY
+
+      migrate_in(delay, MIGRATION, ['group', 'up', *range])
+    end
+  end
+end