DEV: Migrate shelved_notifications#notification_id to bigint (#28549)

DEV: Migrate shelved_notifications#notification_id to bigint

The `notifications.id` has been migrated to `bigint` in previous commit
799a45a291.

app/models/notification.rb

@@ -1,6 +1,10 @@
 # frozen_string_literal: true
 
 class Notification < ActiveRecord::Base
+  self.ignored_columns = [
+    :old_id, # TODO: Remove when column is dropped. At this point, the migration to drop the column has not been writted.
+  ]
+
   attr_accessor :acting_user
   attr_accessor :acting_username
 

app/models/shelved_notification.rb

@@ -1,6 +1,10 @@
 # frozen_string_literal: true
 
 class ShelvedNotification < ActiveRecord::Base
+  self.ignored_columns = [
+    :old_notification_id, # TODO: Remove when column is dropped. At this point, the migration to drop the column has not been writted.
+  ]
+
   belongs_to :notification
 
   def process
@@ -13,7 +17,8 @@ end
 # Table name: shelved_notifications
 #
 #  id                  :bigint           not null, primary key
-#  notification_id :integer          not null
+#  old_notification_id :integer
+#  notification_id     :bigint           not null
 #
 # Indexes
 #

db/migrate/20240826121501_add_big_int_shelved_notifications_notification_id.rb

@@ -0,0 +1,30 @@
+# frozen_string_literal: true
+
+class AddBigIntShelvedNotificationsNotificationId < ActiveRecord::Migration[7.0]
+  def up
+    # Create new column
+    execute "ALTER TABLE shelved_notifications ADD COLUMN new_notification_id BIGINT NOT NULL DEFAULT 0"
+
+    # Mirror new `notification_id` values to `new_notification_id`
+    execute <<~SQL.squish
+      CREATE FUNCTION mirror_user_badges_notification_id()
+      RETURNS trigger AS
+      $$
+      BEGIN
+        NEW.new_notification_id = NEW.notification_id;
+        RETURN NEW;
+      END;
+      $$
+      LANGUAGE plpgsql
+    SQL
+
+    execute <<~SQL.squish
+      CREATE TRIGGER user_badges_new_notification_id_trigger BEFORE INSERT ON shelved_notifications
+      FOR EACH ROW EXECUTE PROCEDURE mirror_user_badges_notification_id()
+    SQL
+  end
+
+  def down
+    raise ActiveRecord::IrreversibleMigration
+  end
+end

db/migrate/20240826121502_copy_shelved_notifications_notification_id_values.rb

@@ -0,0 +1,20 @@
+# frozen_string_literal: true
+
+class CopyShelvedNotificationsNotificationIdValues < ActiveRecord::Migration[7.0]
+  disable_ddl_transaction!
+
+  def up
+    min_id, max_id = execute("SELECT MIN(id), MAX(id) FROM shelved_notifications")[0].values
+    batch_size = 10_000
+
+    (min_id..max_id).step(batch_size) { |start_id| execute <<~SQL.squish } if min_id && max_id
+        UPDATE shelved_notifications
+        SET new_notification_id = notification_id
+        WHERE id >= #{start_id} AND id < #{start_id + batch_size} AND notification_id != new_notification_id
+      SQL
+  end
+
+  def down
+    raise ActiveRecord::IrreversibleMigration
+  end
+end

db/migrate/20240826121503_copy_shelved_notifications_notification_id_indexes.rb

@@ -0,0 +1,14 @@
+# frozen_string_literal: true
+
+class CopyShelvedNotificationsNotificationIdIndexes < ActiveRecord::Migration[7.0]
+  disable_ddl_transaction!
+
+  def up
+    execute "DROP INDEX #{Rails.env.test? ? "" : "CONCURRENTLY"} IF EXISTS index_shelved_notifications_on_new_notification_id"
+    execute "CREATE INDEX #{Rails.env.test? ? "" : "CONCURRENTLY"} index_shelved_notifications_on_new_notification_id ON shelved_notifications (new_notification_id)"
+  end
+
+  def down
+    raise ActiveRecord::IrreversibleMigration
+  end
+end

db/migrate/20240826121504_swap_big_int_shelved_notifications_notification_id.rb

@@ -0,0 +1,32 @@
+# frozen_string_literal: true
+
+class SwapBigIntShelvedNotificationsNotificationId < ActiveRecord::Migration[7.0]
+  def up
+    # Necessary to rename columns and drop triggers/functions
+    Migration::SafeMigrate.disable!
+
+    # Drop trigger and function used to replicate new values
+    execute "DROP TRIGGER user_badges_new_notification_id_trigger ON shelved_notifications"
+    execute "DROP FUNCTION mirror_user_badges_notification_id()"
+
+    execute "ALTER TABLE shelved_notifications ALTER COLUMN new_notification_id DROP DEFAULT"
+
+    # Swap columns
+    execute "ALTER TABLE shelved_notifications RENAME COLUMN notification_id TO old_notification_id"
+    execute "ALTER TABLE shelved_notifications RENAME COLUMN new_notification_id TO notification_id"
+
+    # Keep old column and mark it as read only
+    execute "ALTER TABLE shelved_notifications ALTER COLUMN old_notification_id DROP NOT NULL"
+    Migration::ColumnDropper.mark_readonly(:shelved_notifications, :old_notification_id)
+
+    # Rename indexes
+    execute "DROP INDEX IF EXISTS index_shelved_notifications_on_notification_id"
+    execute "ALTER INDEX index_shelved_notifications_on_new_notification_id RENAME TO index_shelved_notifications_on_notification_id"
+  ensure
+    Migration::SafeMigrate.enable!
+  end
+
+  def down
+    raise ActiveRecord::IrreversibleMigration
+  end
+end