migrations: remove accidental extra excessive update triggers

Change-Id: If1bba729e0ccd8939f99a0ad416daf5e80b8b5a6
Reviewed-on: https://gerrit.instructure.com/c/canvas-lms/+/342856
Tested-by: Service Cloud Jenkins <svc.cloudjenkins@instructure.com>
Reviewed-by: Jacob Burroughs <jburroughs@instructure.com>
Migration-Review: Jacob Burroughs <jburroughs@instructure.com>
QA-Review: Cody Cutrer <cody@instructure.com>
Product-Review: Cody Cutrer <cody@instructure.com>

config/initializers/postgresql_adapter.rb

@@ -280,7 +280,7 @@ module PostgreSQLAdapterExtensions
   def add_guard_excessive_updates(table_name)
     # Don't try to install this on rails-internal tables; they need to be created for
     # internal_metadata to exist and this guard isn't really useful there either
-    return if ["schema_migrations", "internal_metadata"].include?(table_name)
+    return if [ActiveRecord::Base.internal_metadata_table_name, ActiveRecord::Base.schema_migrations_table_name].include?(table_name)
     # If the function doesn't exist yet it will be backfilled
     return unless ((Rails.version < "7.1") ? ::ActiveRecord::InternalMetadata : ::ActiveRecord::InternalMetadata.new(self))[:guard_dangerous_changes_installed]
 

db/migrate/20240313153539_remove_guard_triggers_from_internal_metadata_tables.rb

@@ -0,0 +1,37 @@
+# frozen_string_literal: true
+
+#
+# Copyright (C) 2024 - present Instructure, Inc.
+#
+# This file is part of Canvas.
+#
+# Canvas is free software: you can redistribute it and/or modify it under
+# the terms of the GNU Affero General Public License as published by the Free
+# Software Foundation, version 3 of the License.
+#
+# Canvas is distributed in the hope that it will be useful, but WITHOUT ANY
+# WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+# A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
+# details.
+#
+# You should have received a copy of the GNU Affero General Public License along
+# with this program. If not, see <http://www.gnu.org/licenses/>.
+#
+
+class RemoveGuardTriggersFromInternalMetadataTables < ActiveRecord::Migration[7.0]
+  tag :postdeploy
+
+  def up
+    # these triggers may have been accidentally added due to using constant
+    # table names instead of `ActiveRecord::Base.internal_metadata_table_name`
+    operations = ["UPDATE", "DELETE"]
+    [ActiveRecord::Base.internal_metadata_table_name,
+     ActiveRecord::Base.schema_migrations_table_name].each do |t|
+      operations.each do |operation|
+        trigger_name = "guard_excessive_#{operation.downcase}s"
+
+        execute("DROP TRIGGER IF EXISTS #{trigger_name} ON #{connection.quote_table_name(t)}")
+      end
+    end
+  end
+end