Improve two error messages

src/backend/parser/parse_utilcmd.c

@@ -2098,7 +2098,7 @@ transformIndexConstraint(Constraint *constraint, CreateStmtContext *cxt)
 					index_rel->rd_indoption[i] != 0)
 					ereport(ERROR,
 							(errcode(ERRCODE_WRONG_OBJECT_TYPE),
-							 errmsg("index \"%s\" does not have default sorting behavior", index_name),
+							 errmsg("index \"%s\" column number %d does not have default sorting behavior", index_name, i + 1),
 							 errdetail("Cannot create a primary key or unique constraint using such an index."),
 							 parser_errposition(cxt->pstate, constraint->location)));
 

src/bin/pg_upgrade/check.c

@@ -382,8 +382,10 @@ check_new_cluster_is_empty(void)
 		{
 			/* pg_largeobject and its index should be skipped */
 			if (strcmp(rel_arr->rels[relnum].nspname, "pg_catalog") != 0)
-				pg_fatal("New cluster database \"%s\" is not empty\n",
+				pg_fatal("New cluster database \"%s\" is not empty: found relation \"%s.%s\"\n",
-						 new_cluster.dbarr.dbs[dbnum].db_name);
+						 new_cluster.dbarr.dbs[dbnum].db_name,
+						 rel_arr->rels[relnum].nspname,
+						 rel_arr->rels[relnum].relname);
 		}
 	}
 }