DEV: Migrate User#seen_notification_id to bigint (#28572)

`Notification#id` was migrated to `bigint` in 799a45a291

app/models/user.rb

@@ -1,6 +1,10 @@
 # frozen_string_literal: true
 
 class User < ActiveRecord::Base
+  self.ignored_columns = [
+    :old_seen_notification_id, # TODO: Remove when column is dropped. At this point, the migration to drop the column has not been written.
+  ]
+
   include Searchable
   include Roleable
   include HasCustomFields
@@ -2251,7 +2255,6 @@ end
 #  created_at                :datetime         not null
 #  updated_at                :datetime         not null
 #  name                      :string
-#  seen_notification_id      :integer          default(0), not null
 #  last_posted_at            :datetime
 #  password_hash             :string(64)
 #  salt                      :string(32)
@@ -2287,6 +2290,7 @@ end
 #  last_seen_reviewable_id   :integer
 #  password_algorithm        :string(64)
 #  required_fields_version   :integer
+#  seen_notification_id      :bigint           default(0), not null
 #
 # Indexes
 #

db/migrate/20240827063715_add_new_seen_notification_id_to_users.rb

@@ -0,0 +1,29 @@
+# frozen_string_literal: true
+class AddNewSeenNotificationIdToUsers < ActiveRecord::Migration[7.1]
+  def up
+    # Create new column
+    execute "ALTER TABLE users ADD COLUMN new_seen_notification_id BIGINT NOT NULL DEFAULT(0)"
+
+    # Mirror new `seen_notification_id` values to `new_seen_notification_id`
+    execute <<~SQL.squish
+      CREATE FUNCTION mirror_users_seen_notification_id()
+      RETURNS trigger AS
+      $$
+      BEGIN
+        NEW.new_seen_notification_id = NEW.seen_notification_id;
+        RETURN NEW;
+      END;
+      $$
+      LANGUAGE plpgsql
+    SQL
+
+    execute <<~SQL.squish
+      CREATE TRIGGER users_seen_notification_id_trigger BEFORE INSERT OR UPDATE ON users
+      FOR EACH ROW EXECUTE PROCEDURE mirror_users_seen_notification_id()
+    SQL
+  end
+
+  def down
+    raise ActiveRecord::IrreversibleMigration
+  end
+end

db/migrate/20240827063908_copy_users_seen_notification_id_values.rb

@@ -0,0 +1,19 @@
+# frozen_string_literal: true
+class CopyUsersSeenNotificationIdValues < ActiveRecord::Migration[7.1]
+  disable_ddl_transaction!
+
+  def up
+    min_id, max_id = execute("SELECT MIN(id), MAX(id) FROM users")[0].values
+    batch_size = 10_000
+
+    (min_id..max_id).step(batch_size) { |start_id| execute <<~SQL.squish } if min_id && max_id
+        UPDATE users
+        SET new_seen_notification_id = seen_notification_id
+        WHERE id >= #{start_id} AND id < #{start_id + batch_size} AND new_seen_notification_id != seen_notification_id
+      SQL
+  end
+
+  def down
+    raise ActiveRecord::IrreversibleMigration
+  end
+end

db/migrate/20240827064121_swap_seen_notification_id_with_seen_notification_id_on_users.rb

@@ -0,0 +1,26 @@
+# frozen_string_literal: true
+class SwapSeenNotificationIdWithSeenNotificationIdOnUsers < ActiveRecord::Migration[7.1]
+  def up
+    # Necessary to rename and drop columns
+    Migration::SafeMigrate.disable!
+
+    # Drop trigger and function used to replicate new values
+    execute "DROP TRIGGER users_seen_notification_id_trigger ON users"
+    execute "DROP FUNCTION mirror_users_seen_notification_id()"
+
+    # Swap columns
+    execute "ALTER TABLE users RENAME COLUMN seen_notification_id TO old_seen_notification_id"
+    execute "ALTER TABLE users RENAME COLUMN new_seen_notification_id TO seen_notification_id"
+    execute "ALTER TABLE users ALTER COLUMN old_seen_notification_id DROP NOT NULL"
+    execute "ALTER TABLE users ALTER COLUMN old_seen_notification_id DROP DEFAULT"
+
+    # Keep old column and mark it as read only
+    Migration::ColumnDropper.mark_readonly(:users, :old_seen_notification_id)
+  ensure
+    Migration::SafeMigrate.enable!
+  end
+
+  def down
+    raise ActiveRecord::IrreversibleMigration
+  end
+end

lib/tasks/db.rake

@@ -259,7 +259,12 @@ task "db:migrate" => %w[
     ActiveRecord::Tasks::DatabaseTasks.migrate
 
     SeedFu.quiet = true
+
+    begin
       SeedFu.seed(SeedHelper.paths, SeedHelper.filter)
+    rescue => error
+      error.backtrace.each { |l| puts l }
+    end
 
     Rake::Task["db:schema:cache:dump"].invoke if Rails.env.development? && !ENV["RAILS_DB"]