K8s: Fix legacy stats (#99623)

pkg/storage/unified/federated/stats.go

@@ -31,7 +31,17 @@ func (s *LegacyStatsGetter) GetStats(ctx context.Context, in *resource.ResourceS
 
 	rsp := &resource.ResourceStatsResponse{}
 	err = helper.DB.WithDbSession(ctx, func(sess *sqlstore.DBSession) error {
-		fn := func(table, where, g, r string) error {
+		fn := func(table, where, g, r string, existCheck bool) error {
+			// if existCheck is true, do not error out if the table does not exist
+			if existCheck {
+				exists, err := sess.IsTableExist(helper.Table(table))
+				if !exists {
+					return nil
+				} else if err != nil {
+					return err
+				}
+			}
+
 			count, err := sess.Table(helper.Table(table)).Where(where, info.OrgID, in.Folder).Count()
 			if err != nil {
 				return err
@@ -47,25 +57,25 @@ func (s *LegacyStatsGetter) GetStats(ctx context.Context, in *resource.ResourceS
 		group := "sql-fallback"
 
 		// Legacy alert rule table
-		err = fn("alert_rule", "org_id=? AND dashboard_uid=?", group, "alertrules")
+		err = fn("alert_rule", "org_id=? AND dashboard_uid=?", group, "alertrules", false)
 		if err != nil {
 			return err
 		}
 
 		// Legacy dashboard table
-		err = fn("dashboard", "org_id=? AND folder_uid=?", group, "dashboards")
+		err = fn("dashboard", "org_id=? AND folder_uid=?", group, "dashboards", true)
 		if err != nil {
 			return err
 		}
 
 		// Legacy folder table
-		err = fn("folder", "org_id=? AND parent_uid=?", group, "folders")
+		err = fn("folder", "org_id=? AND parent_uid=?", group, "folders", true)
 		if err != nil {
 			return err
 		}
 
 		// Legacy library_elements table
-		err = fn("library_element", "org_id=? AND folder_uid=?", group, "library_elements")
+		err = fn("library_element", "org_id=? AND folder_uid=?", group, "library_elements", false)
 		if err != nil {
 			return err
 		}