SET @saved_dbug = @@SESSION.debug_dbug; set session debug_dbug="+d,optimizer_innodb_icp"; drop table if exists `t1`; Warnings: Note 1051 Unknown table 'test.t1' create table `t1` (`c` bigint, key(`c`),`a` int)engine=innodb; insert into `t1` values(2,2); delete `t1` from `t1` `a`, `t1` where `a`.`a`=`t1`.`c` ; drop table `t1`; SET debug_dbug= @saved_dbug;