Remove temporary index used for backfilling

The commit adds a migration to remove an index
that was used for backfilling resource_link_events table.

Changelog: other

db/post_migrate/20230712020407_remove_temporary_index_from_system_note_metadata.rb

+# frozen_string_literal: true
+
+class RemoveTemporaryIndexFromSystemNoteMetadata < Gitlab::Database::Migration[2.1]
+  disable_ddl_transaction!
+
+  INDEX_NAME = 'tmp_index_for_backfilling_resource_link_events'
+  CONDITION = "action='relate_to_parent' OR action='unrelate_from_parent'"
+
+  def up
+    remove_concurrent_index_by_name :system_note_metadata, INDEX_NAME
+  end
+
+  def down
+    add_concurrent_index :system_note_metadata, :id,
+      where: CONDITION,
+      name: INDEX_NAME
+  end
+end

db/schema_migrations/20230712020407

+3dc44ced12562d7846fcdc0ad956993705b13f0ecc2418d6ef1853337eea2fff
\ No newline at end of file

db/structure.sql

@@ -33725,8 +33725,6 @@ CREATE INDEX tmp_index_ci_job_artifacts_on_expire_at_where_locked_unknown ON ci_
 CREATE INDEX tmp_index_cis_vulnerability_reads_on_id ON vulnerability_reads USING btree (id) WHERE (report_type = 7);
-CREATE INDEX tmp_index_for_backfilling_resource_link_events ON system_note_metadata USING btree (id) WHERE (((action)::text = 'relate_to_parent'::text) OR ((action)::text = 'unrelate_from_parent'::text));
-
 CREATE INDEX tmp_index_for_null_member_namespace_id ON members USING btree (member_namespace_id) WHERE (member_namespace_id IS NULL);
 CREATE INDEX tmp_index_for_project_namespace_id_migration_on_routes ON routes USING btree (id) WHERE ((namespace_id IS NULL) AND ((source_type)::text = 'Project'::text));