add index on error_reports.user_id

Change-Id: I3174c8cf81c135a74c3c1b56c78acb7b7410ae06
Reviewed-on: https://gerrit.instructure.com/c/canvas-lms/+/338754
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>

db/migrate/20240125213845_add_error_reports_user_id_index.rb

@@ -0,0 +1,27 @@
+# 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 AddErrorReportsUserIdIndex < ActiveRecord::Migration[7.0]
+  tag :postdeploy
+  disable_ddl_transaction!
+
+  def change
+    add_index :error_reports, :user_id, algorithm: :concurrently, if_not_exists: true, where: "user_id IS NOT NULL"
+  end
+end