create table t1(keyc int primary key, c char(100)) engine = innodb;
begin;
commit;
begin;
update t1 set c = 'MariaDB';
update t1 set c = 'InnoDB';
set global debug_dbug = '+d,ib_undo_trunc_before_truncate';
commit;
FOUND 1 /ib_undo_trunc_before_truncate/ in mysqld.1.err
begin;
update t1 set c = 'MariaDB';
update t1 set c = 'InnoDB';
set global debug_dbug = '+d,ib_undo_trunc_before_ddl_log_end';
commit;
FOUND 1 /ib_undo_trunc_before_ddl_log_end/ in mysqld.1.err