Set up replica identity index for lti line items

closes INTEROP-6356
flag=none

Test plan
- Verify that the replica identity index has been
  created
- Verify the replica identity for lti_line_items
  has been set to index (SELECT relname, relreplident
  FROM pg_class WHERE relname = 'lti_line_items';)
- Ensure the old root_account_id index has been
  removed for the table

Change-Id: I93b89f9b3c848f0902f5db71252a360962974431
Reviewed-on: https://gerrit.instructure.com/c/canvas-lms/+/253274
Tested-by: Service Cloud Jenkins <svc.cloudjenkins@instructure.com>
Reviewed-by: Weston Dransfield <wdransfield@instructure.com>
QA-Review: Weston Dransfield <wdransfield@instructure.com>
Product-Review: Mysti Lilla <mysti@instructure.com>

db/migrate/20201119000004_add_replica_identity_for_lti_line_items.rb

@@ -0,0 +1,34 @@
+# frozen_string_literal: true
+
+#
+# Copyright (C) 2020 - 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 AddReplicaIdentityForLtiLineItems < ActiveRecord::Migration[5.2]
+  tag :postdeploy
+  disable_ddl_transaction!
+
+  def up
+    add_replica_identity 'Lti::LineItem', :root_account_id, 0
+    remove_index :lti_line_items, name: 'index_lti_line_items_on_root_account_id', if_exists: true
+  end
+
+  def down
+    add_index :lti_line_items, :root_account_id, algorithm: :concurrently, if_not_exists: true
+    remove_replica_identity 'Lti::LineItem'
+    change_column_null :lti_line_items, :root_account_id, true
+  end
+end

spec/lib/data_fixup/populate_root_account_id_on_models_spec.rb

@@ -702,13 +702,6 @@ describe DataFixup::PopulateRootAccountIdOnModels do
       end
     end
 
-    context 'with Lti::LineItem' do
-      it_behaves_like 'a datafixup that populates root_account_id' do
-        let(:record) { line_item_model(course: @course) }
-        let(:reference_record) { @course }
-      end
-    end
-
     context 'with learning outcomes' do
       let(:outcome) { outcome_model }
       let(:alignment) { outcome.align(assignment, @course) }
@@ -769,13 +762,6 @@ describe DataFixup::PopulateRootAccountIdOnModels do
       end
     end
 
-    context 'with Lti::LineItem' do
-      it_behaves_like 'a datafixup that populates root_account_id' do
-        let(:record) { line_item_model(course: @course) }
-        let(:reference_record) { @course }
-      end
-    end
-
     context 'with MasterCourses::*' do
       let(:content_migration) { @course.content_migrations.create!(user: @user) }
       let(:child_course) { course_model(account: @course.account) }